Thursday, November 10, 2016

Replacing Refrigerator Seals

We noted this year that the refrigerator was not as cool as before. We had to set it to the coldest setting and then it was only around 42. Before this year, on the mid-range setting it stayed about 38. The DW thought to do the dollar bill test. That found the seals needed to be replaced. [It a bill slips easily between the seal and the frame, the seals need replacing] No complaints, the unit is nine years old and unlike the one in the house, it’s subject to both freezing and 100 degree temps. 

I found Dometic seals on eBay for less than direct from Dometic. We have an RM2662 unit and the replacement seals are part number 3108704374. Check your model before ordering. We ordered from hard2findrvpart. The cost was a pricey $117.

The kit ships with double sided tape and a small tube of food quality silicon. I talked with the PM at hard2findrvpart and he advised to toss the tape and get a bigger tube of silicon because they found the tape will release. Lowe’s has DAP Commercial Kitchen Silicone Specialty Caulk which should work.

To remove the doors, you will need two 10mm wrenches. There is a plastic cap topping the pivot pin for freezer door. When that is removed, the mystery of how the doors come off will be revealed.

Removing the old seals will take two hours with a razor knife. The factory seals are installed in a channel and you will have to remove them from the channel. They seals were installed before the two pieces of the door were snapped together. There is no way to unsnap them. Hence the long time to cut them out. Do not try to pull the seal out. You will probably break the thin plastic. And that would mean a new door.

The new seals lay flat on the door, not in the channel. Hence the need for a good sealant.

Monday, October 24, 2016

My Thoughts On Towing

I don't claim to know it all.

Why Tow

It's a life style choice. We would not travel without our Jeep. We take our Lazy Daze places many would not. We take the Jeep to the places the LD can not go. If your traveling style means short duration trips, full hooks and stopping at scenic overlooks. You should be fine without a toad.

What To Tow

Unless you intend to do some serious off-road wheeling, I would discourage getting a TJ or JK Jeep. They are special purpose vehicles for rock climbing, etc. If you want the convenience of a transfer case for towing, but don't intend to drive the Moab trails, you would save weight and money getting an older Grand Cherokee or a newer Renegade. 

If you don't need a Jeep, there are some other vehicles, such as the Forester, which can be towed four down with few restrictions.

Got to have a Jeep? Consider the lighter weight TJ model that was built through 2006. If you want a new JK Jeep, consider the lighter 2DR rather then the popular 4DR. Understand that the rear seat on a 2DR is only suitable for dogs and small kids, but it's lighter and turns sharper than the Unlimited. Our rear seat came out the day we brought the Jeep home.

The Hitch

An ongoing topic in the Lazy Days forum is towing over 4,000 pounds which is the rated maximum for the factory hitch. "Beefing up" the hitch is the common suggestion. What constitutes "beefing" is nebulous. How does one find a "good hitch shop". I am not willing to trust that just anyone knows how to do it. All I can say is that doubling the attachment to the frame might be the way to go. That seems like a simple task to me. Weld on two additional braces. Maybe that's all that's required.

We have towed a 4,250 pound Jeep for 95,000 miles on the factory hitch. Since 10% is a common engineering safety margin I am comfortable. I did upgrade the bumper bolts to Grade 8 with larger washers. I found several loose nuts in the process. I used blue Locktight when I put on the new bolts. The bolt upgrade may have increased the tow capacity? Whatever you are towing this is a MUST MOD. Thanks to Larry Wade for this excellent improvement.

September, 2016
I followed Ed Daniels into a hitch shop in Moab, UT. Ed has a TK. The shop owner, Ben Wilson, did not think it needed anything extra to safely tow a 2016 Wrangler. Ed said he liked to tow down rough dirt roads. So Ben added a corner gusset to "beef it" up. Ben looked at my MB and saw no way to add any structural integrity. He drew out the TK design and compared it to the MB design. Way different. He saw no signs of metal fatigue after towing 95,000 miles. No wrinkles in the paint that would indicate the metal has been flexed. I felt better. I asked him to tack weld the adjustable part of the hitch, so it could not move if the bolts ever came loose again. And left feeling better about the LD hitch. If you are in the Moab area and want a pro to check yours out, the man to see is Ben Wilson at 435-260-2044.


Larry Wade's backing plate


 Ed Daniel's TK mod
 Ed Daniel's TK mod

Our MB tack welded just to prevent any movement in case of a loose bolt

The Crux Of The Matter

If I were looking at a used LD I would be leery of one that had a beefed up hitch. I would wonder exactly how much they had been towing? There is not only the 4,000 hitch limit, there is the almost ignored 20,000 pound GCWR. That rating decreases as the elevation increases. I would wonder how the extra weight has affected the transmission? Did the owner monitor the transmission temperature with a gauge? How often was the fluid changed. I would look at the color of the fluid. 

Downhill, the extra weight is stressing two components, the transmission and the brakes. Assuming you are using Tow Haul and allowing the engine to partially brake the decent, the  extra weigh can spin the transmission toward the red line. Using the brakes more heats the rotors. Have you priced those lately? 2008 rigs come with larger rotors that should help. [Had I known Ford was going to make that change, I would have waited a few months to place the order]

It's balancing act to get the toad brakes to engage correctly. You sure don't want them coming on too hard and braking the Lazy Daze. The ability to set when and how hard the toad brakes come on are an advantage of systems like SMI makes. 

Important, But Neglected GCWR

You can move your rock collection from the LD to the toad axle, but all of the weight counts toward the GCWR. There is no free lunch. 

The GCWR is reduced 2% per 1,000 feet of elevation. This applies to ALL E450 chassis with the V10 engine.

An example:

We unhook, if we are going over 6,000 feet for any distance. Think of that long steep grade west of Denver. Our MB is 13,700 + 4,250 for the Jeep, for a total of 18,000 -  inside the max GCWR of 20,000 at sea level, but not above 5,000 feet. Folks, you should be just as concerned about the GCWR as the hitch limit.

Don't care for my example? Think you can load up the toad and have that free lunch? Here's what Wikipedia has to say on GCWR.

Bottom line, if your are towing much over the rated capacity of the hitch, it's a good thing to have it doubly connected to the frame. It's is important to weigh both vehicles, to monitor your transmission temperature and to not tow at higher elevations. And know that a informed buyer may see the beefed up hitch as a concern.

Don Malpas

See also http://www.lazydazeowners.com/index.php?topic=28840.0

and

http://lazydazearticles.blogspot.com/2011/03/strengthen-your-hitch.html

Tuesday, October 18, 2016

Leaking Toilet Bowls

My Approach to Leaking Toilet Bowls

Bill Atkins posted a good article on toilet bowl leaking (http://lazydazearticles.blogspot.com/2009/08/toilet-bowl-seal-replacement.html), but included dealing with problems with the flush mechanism and the base.  This article takes on a simpler task - water leaking out of the bowl, but not onto the floor, meaning you need to replace the upper seals.  Parts of this article are purely my own thing, and I have not found anything published to support my approach.  They work for me, and I am sharing my process with you.  I am not saying that I recommend that you do the same.  I will flag those parts in bold, so you can decide if you want to try what I do.  It is written with the assumption that you have never, or rarely, dealt with this.  Maybe you are like me my first time, dreading and fearful of the task.  I have provided as much detail as I could, to help you through a task that really is pretty simple.

Few people I have talked with do what I do.  Most have repeat leakage without knowing why.  It is like a good paint job - it is mostly in the surface prep.

If water does not remain in your toilet bowl, you have a leak - somewhere.  It can be in three and only three places.  Let’s start by giving names to the parts for discussion.  These may not be “by the book” names but they work for me.

The bowl - This is the toilet itself, the porcelain part with a hole in the bottom and a rim around the top.

The flush pedal - This is the pedal to the left of the bowl as you face it.

The flush nozzle - This is the connection to the back of the bowl that feeds water into the bowl’s rim to rinse the bowl.

The flush spray - This is the hand held spray used to help rinse the bowl.

The flush dome - This is the curved plastic part that closes the hole at the bottom of the bowl, and opens when you press the flush pedal down.

The upper seals - These are the two neoprene gaskets whose edges can be seen between the bowl and the flush dome.  There are two - a thick upper seal and a thin lower seal.

The pedestal cover - This is the plastic part that splits near the axle of the flush pedal and covers the black pedestal base, the split ring and the band clamp.

The split ring or half clamp - This is a two piece ring with a V-shaped inner surface that pulls the bowl and the pedestal base together.

The band clamp - This is a clamp that, when tightened, pulls the two pieces of the split ring together, locking the bowl to the pedestal base.

The plastic pedestal base - This is the black plastic base on which the bowl sits.

I think that covers the parts.  Let’s talk about the possibilities for leaking.  For water to get out of the bowl, there are only three possibilities.  The water can seep between the bowl and the thick upper seal, eventually getting to the interior flanges that stiffen the plastic pedestal base.  This water can be the source of odors, as there is a slight ability for air to escape past the outer edge of the plastic pedestal base.  Water can also seep between the thick upper seal and the thin lower seal, though unlikely, again getting to the flange area in the plastic pedestal base.  Finally, water can seep past the thin lower seal and the flush dome, dripping into the black tank.  Just like stalactites forming in a cave, moisture containing calcium from a hard water source and urine salts from us, sitting on the dome below the seals and evaporating, leaves behind minerals.  As the deposits grow, the seal becomes worse and worse.

Why does a leak happen?  If you just changed the seals and it leaks, either the mating surfaces were not clean, the seals were not aligned properly, or the half clamps were not tightened sufficiently.  If the seals have been in place for a while and they slowly begin to leak, foreign matter is compromising the seals, either between the bowl and the thick upper seal, between the two seals, or between the thin lower seal and the flush dome.  A little chemistry - once a crystal or mineral deposit begins to form, it attracts more material to it.  Deposits will grow, even between well-seated surfaces.  This is what causes the seals to fail.  There is one more possibility - the flush dome might have shifted out of alignment, preventing a seal, but that is beyond this article.  See Bill’s article for that condition.

The most likely scenario is foreign matter accumulation.  That can happen in several ways.  Liquid waste contains minerals and salts.  Crystallization and accumulation over time can cause a leak.  When it happens, it is time to change the seals.  That is what the remainder of this article focuses on.

Before starting, you will need new seals, white vinegar, an aluminum pan large enough for the bowl to sit in it with vinegar in the pan, dry silicone lube spray, vaseline, a garbage bag, a socket set with a 5/16” socket and an extension, a straight blade screwdriver, an old toothbrush, a scrub brush, a spray cleaner such as Fantastic or 409, Pledge spray wax or similar, lots of paper towels, and if you can find one, a bulb syringe with a small tip.  You will want rubber or latex gloves.  My bowl seal kit is #385311462.  Check your toilet model to be sure you have the right seals.   

First, turn off the water, and flush until there is no more water in the bowl. 

Close windows and doors, making the RV as air tight as possible.  Open the bathroom vent slightly and switch the fan OFF.  Open the other vent and switch the fan to high, with the fan set so it is pulling air IN, not out.  This will create a positive pressure in the RV so odors from the open tank are pushed down into the tank, giving you an odor-free work environment.

Remove the toilet seat and seat back.  There are screws by the seat hinges that hold them in place.  With a flat blade screwdriver, pop the covers up to access the screw heads and reach behind the bowl to hold the screw bases.  Unscrew the screws, and set the pieces aside.

The pedestal cover splits at the flush mechanism at the base of the flush pedal.  You may find you need to remove the trim on the flush pedal to do this, but I can usually get the pedestal cover off with a little fussing and wiggling.  Pressing the lower edge of the cover at the seam behind the flush mechanism, front side right at the bottom with the screwdriver usually does it for me.  Remove the pedestal cover and set it aside for cleaning if there is any sign of staining or dried urine.  If you have ever had male kids visit, I can almost guarantee there will be some.

Feel the band clamp at the back of the bowl.  There is a nut there.  With the socket on the extension and ratchet, loosen the nut until the band clamp can be slid down off the half clamp or split ring.  Remove both parts of the half clamp.  As with the pedestal cover, look for staining or deposits and if present, clean before re-assembly.

The bowl is now loose, so be careful not to push it off the base or drop it.

Reach behind the bowl and feel the flush nozzle where it attaches to the bowl.  This is a rubber or soft plastic friction connection.  You need to remove the nozzle.  it pulls straight out, but is not easy.  I do it by tilting the bowl toward me to get more room, and by twisting the nozzle in a rotating fashion as I am pulling it out of the hole in which it is seated.

Put the aluminum pan in the shower.  Lift the bowl off the base and put it in the pan.  Be careful to have a good hold so you do not drop the bowl.  Using a funnel, tip the bowl toward the front and pour a substantial amount of vinegar into the hole at the back where the nozzle connected.  Your objective here is to first douse the ring area, which distributes rinse water around the bowl, with vinegar, then to have enough vinegar in the bottom of the pan so any crystallized salts on the bottom of the bowl have time to soften for removal.  If you just pour vinegar into the pan, it will deal with the base of the bowl, but any mold in the ring will not be touched.

OK, back to the toilet base.  You are now looking at the two seals sitting above the flush dome.  There is a notch in the edge of the seals.  Note how the notch is positioned to fit on the plastic pedestal base, so the replacement seals will go in the right way.  Remove the two seals and drop them in the trash bag.  You are now looking at the flush dome.  Odds are, the surface will have an accumulation of salts.  Dribble some vinegar on the flush dome.  Roll up some paper towels, drench them in vinegar, and form a ring on the flush dome with them to hold vinegar in contact with the salts.  Let it sit to soften any deposits.  Occasionally, dribble some more vinegar on the dome.

While the vinegar is doing its job, let’s deal with the flange area in the plastic pedestal base.  Odds are, it will have liquid partially or fully filling the spaces between the flanges.  Remove the liquid.  I use a bulb syringe, but it can be blotted up with paper towels and patience, by rolling the paper towels into  a shaft and sticking the end into the flange so the liquid is soaked up.  

Clean any stuff that you set aside for cleaning.  You CAN turn the water back on and use the shower to do this.  Just be careful not to press down the flush pedal if you do so.  Get those parts squeaky clean and dry.

OK, turn the bowl upside down.  Look at the base around the hole where the bowl will rest on the seals.  Most likely, you will see a ring of yellowish deposits.  Scraping with the side of the screwdriver will usually clean those deposits.  Once the deposits are removed, feel the surface.  If you feel ANY roughness, you need to get this smooth.  My first time doing this was after three years of fulltiming, and there was a lot of accumulation of very hard material there.  I needed to use a file, then sandpaper, to get rid of the salt encrustation.  (This is the first of the things that I do.  If you try it, be very careful not to damage the porcelain, and just remove the salts.  It took some patience that first time, but has been simple since then.)  You want to get rid of every salt or mineral present, as any remaining will attract more salts, speeding the regrowing of the crystals.  After that first, very hard deposit, my future seal changes, done annually, do not need real aggressive cleaning.  I scrape with the side of the screwdriver, popping the hard stuff off, then I scrub any remainder.  An old toothbrush (not Dorothy’s, Don) with vinegar usually does the trick.  When all salts have been removed, I add more vinegar to the inside of the rim and scrub with a scrub brush to get the underside of the rim clean.  I then rinse the bowl thoroughly with hot water from the shower, scrub all surfaces in the bowl with a scrub brush and spray cleaner, and rinse again.  I fold up and discard the aluminum pan, leaving the bowl upside down on a number of paper towels to protect the shower base from scratching.  I dry the base of the bowl where it will mate with the thick upper seal.

Now it is time to clean the flush dome.  Hopefully, vinegar and the toothbrush will be enough.  I have encountered quite hard deposits that I remove by VERY careful scraping with the side of a flat blade screwdriver, finishing with a very fine sandpaper until the flush dome is smooth and clean.  (This is the second of the things I do that is not supported.  If you slip and scratch the flush dome, you will have to replace it.)  The best way is to soak with vinegar to soften deposits, then scrape with a material such as wood or plastic that will not damage the flush dome, then soak and scrape again, until all deposits are gone.

With the spray cleaner and paper towels, clean the flush dome thoroughly and rinse, then dry it.  Now, give it several coats of Pledge spray wax.  Your objective is to wind up with a thoroughly smooth, clean flush dome with a waxed surface that will seal well to the thin lower seal.

I then spray the underside of the thin lower seal with dry silicone lube (my own idea) and position it on the plastic pedestal base.  The intent of the lube is to promote smooth sliding of the flush dome against the seal.

Next, I rub a very thin film of vaseline on the upper surface of the thin lower seal and the lower surface of the thick upper seal.  I do NOT gob it on, but apply just enough to get a shiny surface.  This promotes a very good seal between the two neoprene surfaces.  (Again, this is my own idea, not supported.  Vaseline, like all petroleum products, degrades neoprene rubber.  None of the vaseline uses are necessary for re-assembly.  My own opinion is that a thin film improves the seal and reduces water adhesion so rinsing is more thorough.)  Mate the two seals, making sure they are aligned properly.

Now it is time to place the bowl on the upper seal.  First, turn the water off and drain the line so if you bump the flush pedal, you won’t spray the room.  (I do a thin film of vaseline on the top of the thick upper seal and on the dried bottom of the bowl where it contacts the seal.  Again, this is my own thing, but the ONLY times I have found the flange area dry or nearly so on seal changing is when I have previously done this.  Also, cleaning the bottom of the bowl got much easier after I began using a thin film of vaseline there.)  Place the bowl on the seals in the approximate position.  Re-insert the nozzle in the back of the bowl, seating it fully.  Now position the bowl carefully.  You have it right when, if you stand over the bowl and look straight down, you see a uniform black ring from the seals in the hole.

Position the split ring half clamps in place, with the front, with the two tabs, together and the rear having a gap.  Place the band clamp over the split ring to hold it in place.  This may take a bit of jiggling and juggling to get the split ring and the band clamp in place.  Take the time to get it right.  The two parts of the split ring should be straddling the bottom of the bowl and the top of the plastic pedestal base, with the split ring joined in the front, apart at the back, and the band clamp sitting evenly in the groove on the split ring all the way around.  (Before I do this, I spray the bowl base and the inside of the split ring pieces with dry silicone lube.  As you tighten the band clamp, the split ring will pull the pedestal base and the bowl together.  The surfaces need to slide on the split ring for this to happen.  I find the dry lube to help this process, but support for this cannot be found anywhere.)  Make sure the band clamp nut is at the back of the bowl, else the pedestal cover will not fit in place.  Tighten the band clamp until the split rings are in place and the band clamp is snug but not yet tight.  Check the alignment of the bowl again and if necessary tweak its position until it is just right.

Now it is time to tighten the band clamp.  You need to do this carefully.  Go too tight, and you can crack the bowl.  Too loose, and the bowl will shift and move with use, causing leaks.  Here is how I do it.  First, I get rid of the ratchet and use a nut driver (like a screwdriver but with an end that allows the attachment of a socket).  If you do not have a nut driver and are using the ratchet, be gentle with that ratchet handle.  Don’t pull too hard.  Snug up the clamp until the resistance to tightening is building noticeably.  Re-assemble the toilet seat and seat back.  Check the bowl alignment.  Now, sit on the bowl and wiggle.  This will compress the seals and gain some slack in the band clamp.  Again, tighten until resistance builds.  Sit.  Wiggle.  Tighten.  Repeat until you are no longer creating slack by wiggling.

Finally, replace the pedestal cover.  Hold it so the bulge is at the top and facing away from you.  Slide it in place beginning on the right, maneuvering it around the back, over the nut, then rotating the edge forward until it seats behind the flush mechanism.  Now rotate the other side around to meet the seam and snap the two edges in place.  It may take a bit of wiggling of the cover to get the two edges to snap together.  

You are done. 


You may notice, however, after a few weeks of use, that the bowl wiggles a bit.  This sometimes happens as the seals continue to compress and the split ring adjusts itself over the bowl and base.  It that occurs, simply tighten the band clamp a bit more.

So, how much time does this take?  Well, I am used to it.  Aside from time soaking in vinegar and cleaning, it takes me about 15  to 20 minutes to dis-assemble and re-assemble.  Changing the seals regularly means I don’t need a lot of time soaking and cleaning, but my last change took about 2 hours, mostly sitting and waiting for vinegar to do its job.


Let’s close with maintenance.  Periodically, get all the water out of the bowl that you can, add about a half inch of white vinegar, and let it sit for a while.  Then, press the flush pedal to open the flush dome and scrub the edges with a stiff brush, removing all the sediment you can.  Do another vinegar soak and scrub, then a thorough rinse with the flush spray.  I do that once a month.

Ken Fears - October, 2016

Tuesday, October 11, 2016

Repainting Front Faux Window Panels


Those faux windows on the front of LD's (up until a few years ago) all seem to suffer from severe fading over time. A number of folks have re-painted the panels, but until Ron B. took the time to document his project, we didn't have any good guidance on to best accomplish this. Here is his report, along with some comments from Larry Wade.

I recently finished re-painting my front 'windows'. Years ago I went through a sleet storm, and the front faux windows were pretty eroded. Their looks went downhill from there.

Getting to it to mask it off was the hard part. First I cleaned it with alcohol, then gently roughed it up with Scotchbrite, then more alcohol.  I used Home Depot Rustoleum gray primer, about one can. I decided to switch to Duplicolor high buildup primer, sanding in between each coat in an attempt to level off the surface. About  two cans. Maybe 10 layers of primer. Then I followed with about two coats  (1 can) of satin black primer. Light sanded 400 grit paper. I could have put some coats of Rustoleum gloss black enamel, but I had some gloss black Appliance paint. It dries to a really shiny hard coat. After I was done I asked some friends why the appliance paint said to not paint over primer and they said that the dried film was meant to be over a hard steel surface and that it would eventually crack by itself over primer. Well it hasn't cracked yet, but I have a can of black gloss enamel in case it does. I had a breeze blowing dust on the surface during painting, and some dusting in spots. (The solvent vehicle evaporates before the paint droplets hit the surface, and leave a poorly adhered 'dusty' coating. Rubbing compound, and wax cleared up that spot. A little sanding of the edge to take off the lip where the masking tape was. Good thing you can't get too close a look at it but I think it looks almost as good as new.

RonB

 Masked and taped - ready for primer

 Final primer coat
 Final coat spray black

Larry's comments: Watching our 2003 LD's front 'windows', and many others, decay within years of purchase, leads me to think that the  black paint used was just something out of a cheap rattle can, not the long lasting, two-part polyurethane paint used on the coach.

The results from repainting the the windows with anything from Home Depot or any other home center is going to decay rapidly. For a more durable finish, use a high quality, two-part spray paint, available through a auto paint shop or online

Some auto paint shops custom mix two-part paints and package it in a special spray can.
This type of spray paint is known a 2K and is sold under the Spraymax brand.
The can has two separate areas, one with paint, the other with the curing agent.  A button on the bottom the can is used to pop an internal bag, releasing the curing agent. Shake the can hard for several minutes. The paint is now ready to use, having a 48 hour pot life, more than long enough for a window job.

2K clear coat: Spraymax
This is what I use for repairing small sections of damaged LD exteriors. It goes on nicely and is easy to use. To match body colors, I remove an exterior hatch cover and take it to the paint store for custom matching.

Or you can buy two-part, gloss black from Eastwood, in a pre-mixed Spraymax can.
2K Aerospray HT Ceramic Engine Paint Gloss Black

2K paints are harmful to breath. Painting should be done outdoors, in well ventilated spaces and you MUST wear an approved respirator. For each job, I buy a new, organic solvent-rated, respirator. I find these 3M respirators to be widely available.
Amazon.com: 3M 07193 Paint Spray Resp. Large: Automotive

When wearing the respirator, if the respirator is properly fitted, there should be absolutely no smell of solvent. The filters have a limited life,  keep them in the Factory sealed bag, until ready to use.
Partially used respirators are handy to wear when dealing with any solvent but if there is any smell of solvent, immediately discard the respirator or change the cartridges, if the respirator has replaceable ones.

And then there is the simple approach used by JOTA: 

I redid mine about 5 years ago. I sanded down the panels to give a rough surface, then taped around the edge, which is a little difficult with the rounded edges. Used Rustoleum semi gloss paint, 3 coats, no primer or sealer. It still looks pretty good after 5 years.

Sunday, September 25, 2016

Hot Water Heater Intro


First, thanks to all who helped put this together - John, Erik, Judy and Andy.  They picked up a number of errors and omissions that helped me make it better.  

This is targeted at water heaters from Atwood, used in Lazy Daze motor homes.  It is NOT applicable to other makes of heaters.  It is not intended to be a detailed or comprehensive guide to troubleshooting your heater.  Rather, the intent is to allow you to become familiar enough with the electronics in the system to understand what is going on, and possibly to identify a failed component if professional help is not available.  Other articles address flushing the heater, and I do not plan to address issues with propane delivery here.

Now the disclaimers - Combining propane and electricity is dangerous.  Do not mess with the system if you do not feel able to do so safely.  Read your Atwood manual for more detail.  If you do not have one, you can download one from http://atwoodmobile.com/manuals/waterheaters/MPD%2093756%20SP%2011.19.07.pdf Their manual has step by step instructions for troubleshooting, and it is recommended that that be your primary resource.

Stay within your skill set.  If you are not comfortable with any of these steps, let a pro do the work.

Do not work on the water heater when the water is hot.

You may want to take pics of everything before you start, but if you only deal with one component at a time, getting things back together is pretty simple.

These water heaters run on 12 volts for the controls and propane for the heat.  There are some 120v heaters out there, but this does not address them.  They have a confusing array of wires running here and there.  When the heater isn’t working right and you are well away from help, it can be a challenge to figure it out.  This article is intended to give you a basic understanding of the parts, what they do, and perhaps how to check them if you are having problems.



Looking at the heater, in the top right corner is the circuit board.  It is the brains of the operation.  It senses what is happening elsewhere in the system and does things like allow propane to flow or not, send a spark to light the propane, monitor the water temperature, and monitor the flame.

To the left of the Board is the brass pressure relief valve.  It has two functions.  If there is too much pressure in the heater, such as from water that is overheated and boiling, it releases pressure rather than allowing the pressure to build and cause a steam explosion.  It is also used to restore or maintain a pocket of air at the top of the heater chamber which cushions the chamber and your plumbing from overpressure as water heats and expands.

Left of the pressure relief valve is the exhaust vent.

Below the pressure relief valve are two thermostats and a device (thermal cutoff) in a clear plastic tube.  The left thermostat, covered by black foam tape, is labeled ECO (Emergency Cutoff).  It shuts down the system if heater temperatures are too high.  It is normally in the closed position, conducting electricity through it, but if it senses temperatures that are too high it will open, cutting off flow of propane.

The right thermostat is the one the system uses to control the water temperature.  When the water is cold, this thermostat is closed, conducting 12 volts through it, and current can flow to the system.  When the water reaches the designated temperature the thermostat opens, cutting off the electricity, and the system cuts off the flow of propane.

Floating about in front of the thermostats is a little electrical part encased in a clear plastic tube.  This is a thermal cutoff.  If there is too much heat in the area behind the thermostats, perhaps from a blocked flue or exhaust vent, a propane leak or some such, this part melts, cutting off power to the system.  

Andy Baird’s “Eureka” talks about the thermal cutoff.  He said, ”Like a fuse, the thermal cut-off is a one-shot device... so if it blows, it must be replaced. This is where it gets interesting. A Google product search on 'atwood thermal cut-off' turned up prices ranging from $16.00 to nearly $23.00. I knew that a simple part like this couldn’t possibly cost that much—somebody, probably Atwood, was tacking on huge markups. But I was able to locate the part in the Newark Electronics catalog for just $2.16—a far cry from the RV dealers’ pricing! Here’s a link to the item.

http://www.newark.com/nte-electronics/nte8096/fuse-thermal-98-c-15a-277v/dp/55R1324?ost=nte8096&selectedCategoryId=&categoryNameResp=All%2BCategories&searchView=table&iscrfnonsku=false

For the record, it's an NTE Electronics #NTE8096 thermal fuse, designed to carry 15A and cut off at 98 degrees Celsius. It's not something you can find in a local Radio Shack store, so I carry a few spares with me just in case. You might want to do likewise.

To be fair, Atwood’s $20.00 replacement part includes two thermal fuses (worth four bucks), some plastic sleeving, and a couple of 3/16" crimp-on lugs (worth a buck, maybe)—but I'm sure most of us can scrounge those items for a lot less than Atwood is charging!”

Below the thermostat and ECO is the propane solenoid valve.  To the right is the mix tube or burner, which mixes air with the propane and turns and directs the air and propane mixture into the burn chamber.  In front of the mix tube outlet, at the entrance to the burn chamber, is a pair of contacts from a white ceramic ignitor, which acts like a spark plug.

Finally, above and left of the solenoid valve is a plug which allows draining of the heater for maintenance such as flushing or storage.

OK, here we go.  When you switch the heater on and the water in the heater is cold, 12 volts should go first to the thermal cutoff, then to the thermostat, then to the circuit board.  What you see on the panel depends on how old your panel is.  On newer panels, the switch operates a green light to show the switch is on, and the board operates a red light, indicating that the startup sequence has begun.  Proper startup is signaled by a red and a green light by the switch over the stove.  On older panels, there is a single red light, controlled by the board, that comes on with the heater startup sequence. 

When the board receives a 12 volt signal, it accepts that as meaning that the thermal cutoff and the thermostat are closed.  Then the board thinks it is safe to begin lighting the burner to heat water.  It signals with a red light by the switch, and begins the startup procedure, sending voltage through the ECO to the solenoid.  If the ECO is closed, that voltage reaches the solenoid, and the solenoid allows the flow of propane.

The board now sends a high voltage pulse to the ignitor.  Between pulses it measures the resistance across the ignitor’s 1/8” gap.  That resistance tells the board whether there is a flame or not.  It should try three times to light the burner.  If no flame is sensed, it will shut down the propane and cease further attempts.  If a flame is sensed, the lights by the switch go to green and it continues the burn until the thermostat opens, at which time it cuts off the flame.

So - what can go wrong?  Let’s assume here that you do not have dead batteries, and that you have ample propane.  What next?

First, there are a lot of spade connectors in the system.  They are subject to corrosion.  If they become corroded, the board will not get good information and the heater will not work right.  So, start by making sure all the connections are clean and free of corrosion.  Connectors can be cleaned with contact cleaner, with a fine abrasive such as a coarse eraser or fine sandpaper, or by other similar means.  When cleaning the contacts on the board, be gentle.  That material is thin.  You do NOT want to abrade it away.

Next, if you have a multimeter, you can check the thermal cutoff, the thermostat and the ECO for an open circuit or even better, for voltage.  All should read closed or very low resistance.  If any read open, you found the problem.  

If anything - corroded contacts on the board or in the heater wiring, a bad switch, a bad wire coming in (rare, but possible), a bad thermal cutoff, or an open thermostat - interrupts the current, the board will not get 12 volts, and you may see a green light by the switch on a newer panel, but not a red light.  On an older panel you will see no light.  So, if you see no red light when you turn the switch on, and you have a voltmeter, start off by measuring the voltage anywhere in that chain from entry wire to thermal cutoff to thermostat to board connector.  If you do not have 12 volts all the way along, the component “upstream” of the check point at which you do not get 12 volts is the failed component.  Replace the part.  

If you do not have a multimeter, and you have a helper, you can test the thermal cutoff and the thermostat and the ECO by bypassing each of these items, one at a time, by unplugging the spade connectors from the device and connecting the two wire ends together.  WARNING - DO NOT USE BYPASSING TO OPERATE THE HEATER, just to troubleshoot it.  The recommended way is to have a helper inside, with the switch off.  Make the bypass connection and have the helper turn the switch on.  If the heater lights, you found the problem.  Turn the switch off immediately (you disconnected a safety device) and reconnect the failed device until you can get a replacement.  Do the thermal cutoff first, then the thermostat, then the ECO.

The Atwood manual gives places where voltage can be checked with a multimeter.  You could have a working ECO, but corroded contacts, leading to low voltage at the solenoid.  If you have a multimeter, do those voltage tests.

OK, you checked and the thermal cutoff, thermostat and ECO and all are showing closed or good, but you have no flame.  The voltage at the solenoid is good.  Is the solenoid operating?  You may be able to hear gas flow if it is.  My hearing is not good enough for that, but yours might be.  Make sure the mix tube is clear of debris, spider webs, etc., then try again.  If the tube is removed to clean, it should be put back in same location and make sure the flame is adjusted to provide the most efficient air gas mixture.  The color of the flame is the indication of this by seeing a good blue flame with a tinge of yellow on the flame tip. Too much air will be noticeable by a louder burn and yellow flame. This adjustment is done by loosening the screw at the beginning of the tube and making the air gap there larger or smaller, then tightening the screw.  This setting should not be done at higher elevations. 

At this point, some guesswork is involved.  If you see no spark at the ignitor electrode tip, then either the ignitor or the board is bad.  If you see a spark but no flame, you may not be getting adequate propane flow, indicating a problem with the solenoid, you may not be getting air mixed with propane, or the spark may be weak or in the wrong place.  If you see a flame that burns briefly before going out, either the ignitor or the board is probably bad, but a blocked mix tube or propane orifice could be to blame.  

Let’s look at the ignitor.  You should hear a tic - tic - tic sound as the ignitor shoots a spark across that 1/8” gap, and unless you are in bright sunlight you should be able to see the blue spark.  You might even see a jet of flame come on, burn briefly, then go out.  Remember, the ignitor does more than just throw a spark.  It also tells the board when a flame is present.  A dirty ignitor, corroded electrodes or a crack in the ceramic can result in improper resistance, shutting down the gas flow.  The ignitor can be removed fairly easily.  The Atwood manual says, “The gap between the sparking probe and the ground probe should be 1/8”. The probes should be clean and free of cracks, flaking and corrosion. Position the probes so that they are in the path of the gas flow. Cracks in the ceramic insulator can also be the source of an intermittent problem. To check for cracks insert a fiber washer or any other type of insulation material in the 1/8” gap between the rods. Remove the gas valve from the circuit and turn the unit on. If you see a spark jumping from the ceramic to the ground rod or bracket, replace the spark probe.”  

If you service the ignitor electrodes, after cleaning the igniter rods the gap adjustment should be made with two pairs of pliers, one to hold the straight rod right above the ceramic to not put undue stress on it while bending the curved rod with the other pair.  If you have gotten the ceramic wet, it is somewhat porous and may take a while to dry completely.  Rain won’t do it, but direct water spray, such as your hand slipping when flushing the heater can do it.  Guess how I know that…  Until it is dry, it may send a bad resistance reading to the board, preventing the heater from working.  A day of dry conditions should deal with a moisture problem. 

OK, the thermal cutoff is good, the thermostat and ECO are good, and you see nothing wrong with the ignitor, but you still have no hot water.  The remaining problems are gas flow and a bad board.  A board is not cheap, but can be replaced fairly easily.  It is NOT RECOMMENDED that you mess with the solenoid or the propane orifice.  There is simply too much risk if you mess something up. If you are confident that propane is flowing, but you have no flame, your problem is pretty much narrowed down to the ignitor or the board.  The ignitor is cheap.  Replace it.  Still no good?  Now, finally, it is time to try replacing the board. 

Hopefully, this will help you understand the heater’s steps and may give you a clue what to look for if you are having problems.  Again, stay within your skill set on this.  With some understanding and a sense of how the parts work together, you may be able to figure it out.  If not, get thee to a qualified service person.

Ken Fears - September 2016


As Editor I can not resist adding a few very minor points to this fine article.

Note the nylon drain plug in the picture, a suggested improvement. One way to easily remove the drain plug is with a socket wrench with an extender and a swivel. That allows you to get around the gas plumbing.

Also note the position of their air/fuel “mixer tube”. It's all the way to the left. That position may yield the bluest flame. You need to know this if you disassemble the tube for cleaning. That needs to be done every few months of use. A few minutes with a wire brush and WD40 will clean it up.

I have my spare thermal fuses in a ziplock bag taped to the inside of the heater cover, so I can find them if I ever need one.

The adjustable thermostat allows you to lower the temperature to the level you find most useful. Some set it so that no cold water needs to be mixed. We keep ours at 120. I think the factory setting is about 140. How do you know what the temp is? You add an aquarium thermometer to the tank.  I guess we need to add a How To for that Andy B improvement. Nothing to it, just place the temp prob under the tank insulation and run the wire to the display.






Friday, June 3, 2016

Getting AC from an inverter to the rear of a MB

Most of our stuff is powered from 12volt, so we don’t have much need for 120.
Things like computers and MiFi are the exception. We use these almost exclusively in the rear of our MB. So that’s where we wanted 120volt. We asked for an outlet there when the rig was built and were turned down.

What follows is a how to specific for MB’s. I have no idea how or if it could be implemented on any other floor plan.

So for both of the people that 1) Have an MB, 2) Want a 120 volts in the rear and 3) Are willing to take on a fairly simple DIY project 4) You do not make the beds into a King - read on.

I mounted the inverter on the wall behind the drivers seat. That was unused space and it is close to the batteries. I used a cheap 1000w inverter from Harbor Freight. It has the same case as the one used by a well known brand and may have the same internals. A hole was drilled through the wall panel behind the drivers seat and another into the battery compartment to run #2 wire to the batteries. I sealed the latter one. The former can not be seen.

I cut an extension cord using the male end to plug into the inverter and ran the cable through the same hole in the panel used for the cables to the batteries. Remove the interior panels in the cabinet under the refer. [Mark each panel so you will know how to put them back. They are not cut square] Make a connection from the extension cord to #14 standard house wire. You want to use this as the stiffness will make it easy to snake the wire to the back of the rig. Do observe correct polarity.

Snake the #14 back over the fresh water tank. There is a small opening in the “wall” to the bath. Use a small child for this. Remove the panel behind the toilet that covers the plumbing and snake the wire through there and through the panel wall behind the shower. Attach the female end of the extension cord you cut and secure it with P clamps to the forward end of bed platform and terminate it adjacent to the factory 120volt outlet in the “hall”.

Step Two.

Mount a power strip in the middle of the rear wall near the top of the carpet. [No holes to show] Run the cable from the power strip under the driver’s side bed to where the wire from the inverter terminates.

When boon docking you plug the cable from the power strip into the wire from the inverter. When on shore power you plug the wire from the power strip into the factory outlet.

Pretty simple actually. 




Saturday, April 30, 2016

CPAP Amp Usage

This post is about conserving DC when using a CPAP while boon-docking.

Any device can be powered from an inverter. But, inverting/converting is not without some loss. Call it a toll fee. Now consider a CPAP that runs on DC voltage, requires a “brick”, that rectangular object on a power cord, to convert AC to DC. In the  RV environment this means inverting the batteries DC power to AC and then the brick converting back to DC. Two toll fees. Both unnecessary, since my CPAP requires DC and the coach batteries have want it needs.

My CPAP unit, a Dreamstation by Respironics, is native 12 volt, that’s why I selected it. It comes with a 120 volt power cord and a brick that converts to 12 volt DC. Normally I would have made up a 12 volt cord for it, but I had to buy a power cord from Respironics, since I could not find a source for the odd size 9mm plug it uses. I now own an $18 length of wire with a cigarette lighter plug on one end and the 9mm plug for the CPAP on the other end.

I did not want to install a female “cigarette plug” over my bed as the Mothership does and have the wire hanging down. So I tapped into the 12 volt house system in the raceway above my bed. [MB] I drilled a hole in the bin floor behind the cornice and dropped the power cord down and then across the bed platform so that it’s totally concealed. The machine lives on a table between the beds.

I went to this trouble to minimize amp usage. Powering it from inverter used 3 amps. Now, usage is 1.7 amps. [That’s without the humidifier which I am yet to use]  That’s about 13.5 amps used during 8 hours. I can live with that. 24 amps was a concern for me.

I suggest that anyone concerned about battery use when boon-docking and that has a CPAP that is 12 volt powered to make or buy a cord to power it direct from the house batteries and save those toll fees.