Replacing The Ignitor on the Refrigerator

I noted the wire from the refrigerator control board to the ignitor was burned and frayed. It still worked but for how long? So for the princely sum of $30, I bought a new one.

Due to rust and overcast skies I could not see how to remove the old ignitor.

The next day with better light, I could see that a screw that held a thin piece of sheet metal that held the ignitor. The screw was rusted in so I cut it with a grinder attachment with a Dremel. 

Before: showing the screw through a piece of sheet metal that holds the ignitor.

The new one

Where the ignitor wire connects to the control board.

To remove the cover of the control board, be in good light and have your glasses on and you may see the writing on the cover that indicates where the two tabs are that need to be squeezed to remove the cover. You may also need to separate the drain hose and remove the cover plate from the AC outlet to get the cover out. With needle nose pliers you can gently get the plug out of the socket on the board.

I cleaned the rusted sheet metal with a wire brush and cleaning strength vinegar, which is a "high test" white vinegar.

Why your refrigerator may not work on propane above 8,000 feet.

From a RV tech:

There are no adjustments to anything that will make a difference. Removing the protective cover around the burner housing to allow more air to get to the burner might help because the problem is a lack of oxygen and cold temps.

This explains what's happening.

• Propane gas will only ignite when the turbulence from jet causes the propane to mix with the air as it shoots out of the orifice.
• Propane ignition requires at least 2.15% but less than 9.6% propane gas.
• At high altitudes, there is less air so the normal orifice is slightly too large and delivers too much propane.
• If the temperature of the tank is also low, the propane density is increased and the 9.6% limit is exceeded.

Propane Limits of Flammability - The lower and upper limits of flammability are the percentages of propane that must be present in a propane/air mixture. This means that between 2.15 and 9.6% of the total propane/air mixture must be propane in order for it to be combustible. If the mixture is 2% propane and 98% air, there will not be combustion. If the mixture 10% propane and 90% air, combustion will not occur. Any percentage of propane in a propane/air mixture between 2.15% and 9.6% will be sufficient for propane to burn.

Contributed by Ed Daniels

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.

ARP Refrigerator Boiler Temperature Controller

I recently installed a gadget that will shut off the refrigerator if the boiler temp exceeds a threshold temperature. Our original refer "bled out" in less than two years and was replaced under warranty. The literature of the vendor, ARP, convinced me that spending $135 was worth it to prevent another failure. I am not a metallurgist, so I can not confirm the vendor's claims, but they seem reasonable to me. Specifically, that metal fatigue is cumulative. Overheat metal enough times and it will fail. Parking unlevel with the refer on will cause the boiler temp to rise. Do it enough times or leave it unlevel long enough and the tube holding the ammonia will crack open.

We park level for the night, but we are guilty of letting it go when parked for lunch or stopping by a friends house for just a short while. Yes, could shut off the refer, but the simple fact is, we forget. If your memory is better than ours, you can save your money and read no further.

[BTW, if your refer "bleds out" you do not need to replace the whole refer, just the working part of it. The part outside. The part that costs one-half of a new refer. The part that does not require removing a window to install it.] 

The device vendor is ARP. The web site is http://www.arprv.com/ Since I had already installed two cooling fans OUTSIDE, I bought the plain Jane model. If you do not already have outside cooling fans and you camp in warm areas, such as the desert SW, you should consider getting the device with fans. On reflection, I should have tossed my existing fans and bought the full boat ARP device with fans and let the device cut the fans off and on as needed.

If you want to install the device inside, also order the additional cost longer wiring. I had enough wire on hand to do the job. The gadget will work fine installed outside in the refer service compartment, but I could not resist having another digital device inside. [As one of the more knowledgable contributors to things Lazy Daze said, You are more anal than I am]

Installation - The manual is written by an engineer. Unless you read engineer, you may be mystified. It is made even more nebulous as it covers all Dometic and Norcold refers at the same time. I got lucky and found one drawing that closely resembled the wiring we had. With a VOM, I was able to make a educated guess of how it must work. I then called the vendor and he confirmed my suspicions.

In the photo below, there is a thermal shut off device on the boiler housing at the right of the picture. This is the Dometic device that is supposed to shut the refer off if the temp exceeds whatever temp the device is set for. [Note, that it will not shut off if the temp approaches, but does not exceed the threshold multiple times]

I found that this wire comes from the control box, carries 12 volts and returns there. This is what needs to power the ARP device. All that needed to be done was to enlarge the loop placing the ARP device in the loop. So to the device inside, I ran two wires one to carry and one return 12 volts. I also ran a ground wire as I could not figure where I might find ground inside the cabinet above the stove. [This is a MB]

Installing the temp sensor required removing the housing shown in the picture above. Then parting the fiberglass so you can clip the sensor to the boiler tube. This requires small hands, as the LD compartment is not really tall enough to make it easy. Be sure to put on thin gloves or spend the rest of the day picking FG out of your hands.

How to run the wires. It ain't fun. Mike Sylvester installed our solar panels and ran wiring from the battery compartment, below the refer access compartment on an MB and up the refer cooling tower to the roof and then through the front wall of the cabinet above the stove and then down to the charger. I used the same path. Mike had left a pull cord anchored to the refer vent on the roof. That helped. [You probably don't already have this pathway, so just drill a small exploratory hole from inside the cabinet, at the top, forward into the cooling tower] 

I elected to hide the device inside the bin as it was slightly larger than the space about the refrigerator which would have been ideal location. Here it is showing the boiler temp. Ours high reading is 190.

Keeping the Refrigerator Cold

Keeping the contents of your refrigerator safely cold (the ideal
temperature is around 37° F.) can be tough, especially in hot
weather. The absorption-type Dometic or Norcold refrigerator used in
your Lazy Daze doesn't cool as fast as the compressor-type unit in
your house, and it's subjected to much greater temperature
fluctuations...so your rig's fridge needs special care if it is to
do its job well. Here are some tips to help you get the best
performance from your RV's refrigerator.

PRE-COOL

If possible, start up the fridge the night before you leave on a
trip, giving it plenty of time to cool down. It can take 12-24 hours
for an RV fridge to reach its optimum temperature, so the more of a
head start you give it, the better.

PRELOAD

Before a trip, freeze a bunch of "Blue Ice" or similar freezable
packs in your freezer at home...then transfer them to the RV's
fridge to jump-start the cooling process.

FILL 'ER UP

You might think that having more stuff in the fridge would make it
work harder, but in the long run the opposite is true: packing the
shelves really helps keep things cold. Think of it this way: any
mass stored inside the fridge--especially water--will "store up
cold" during the night, and then help to retain low temperatures
during the day when the outside temperature is high. A half-empty
fridge experiences much bigger temperature swings than one that is
full. Just loading the unused space with bottles of water made a
huge difference in my old Dometic's ability to maintain a cool
temperature throughout the day when I was in Arizona. So pack those
shelves!

PUT COLD WHERE YOU NEED IT

Speaking of packing shelves, that goes double for your freezer: fill
it up with a mix of food and "Blue Ice" type freezable packs. Not
only will it help keep temperatures down, but if you need to turn
off the fridge (if you prefer to shut it off while driving, for
example), you can transfer the ice packs from the freezer to the
refrigerator section to keep that part safely chilled. Put them back
in the freezer to refreeze overnight.

KEEP THE AIR MOVING

It's important to keep air circulating inside the refrigerator, so
that warm and cold spots don't form. Otherwise you could end up with
spoiled meat and frozen lettuce, even when the "average" temperature
is close to ideal. Buy a Valterra FridgeCOOL--a tiny fan that runs
for weeks on a pair of "D" batteries--and put it on a bottom shelf
where it will help keep the air moving around. It's Camping World
item #6675, and only costs about $17.

Another approach is to insall a small 12-volt fan wired across the interior
light switch contacts.  The interior light acts as a dropping resistor,
slowing the fan down and reducing the current draw to a very low level.
It isn't super powerful but provides enough circulation to keep the thermal
layers broken up.  A couple of zip-ties will keep it in place.  For some photo
details, see http://www.flickr.com/photos/lwade/sets/72157602104742183/

KEEP THE AIR MOVING, PART 2

Something most people don't think about is the heat-exchanger coils
on the back of the refrigerator. But they perform a crucial
function: all the heat that your fridge sucks out of its interior
has to be transferred to the outside air via these coils. If they
don't have good air circulation to carry away that heat, your fridge
won't be able to do its job. That's why there is a vent on top of
your rig above the fridge: to let the hot air escape. But how about
giving it a little help? It's easy to install a solar-powered
Valterra Solar Exhaust Fan under that vent, with a tiny solar panel
that powers it independently of your rig's electrical system. One of
these can make a big difference in hot weather. It's Camping World
item #19710, and costs about $40.

Installing Muffin Fans To Cool The Refrigerator

DON'T OPEN THE DOOR TO CHECK THE TEMPERATURE

Instead, buy an inexpensive (as little as $10) digital
indoor-outdoor thermometer and put its sensor in the fridge, with
the digital readout stuck to the door. Now you can tell how things
are doing without opening the door! Don't worry about the
cable--it's thin enough to snake through the door gasket without
causing any air leaks.

Contributors: Andy Baird, Larry Wade, Don Malpas

Revised 22 Jul 2011

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Cleaning the Refrigerator

.
Some things to remember when you clean your refrigerator.

You want to clean the set of metal fins that sit at the upper back. Below these fins is a short removable shelf, which has a tube/vent that leads to the outside. This is where the condensation runs out of the fridge. This shelf is removable, and right where the tube attaches to the back of the fridge, there's a small catch cup. Today, when I looked in this catch cup, ours was full of goop. How had I missed this all these years? I don't know, but I won't ever miss it again, and you should always check it when you clean the fridge.

Also, at least once a year, go outside and check where the fridge actually drains below the fridge. This opening has a small perforated cap and this can also get clogged with road grunge.

After cleaning both of these openings, blast a bit of canned air till the tube runs clear.

Kate's LD is a 2006. Our 2007 does not have a cap. The entire run of the drain is clear plastic.

Refrigerator

Reference Sources

http://rvmobile.com/Tech/Trouble/CoolingD.htm

http://www.gasrefrigeration.net/faultdiagnosis.htm

The Dometic RM2662 Manual

General Operation

1. The first thing to remember is that RV refrigerators like to be level. Reasonably level is when the coach can be comfortably lived in with everything operating normally. This means no obvious slanting of the coach. Operating the refrigerator when parked and not level can permanently damage the cooling unit. Levelness is not a problem when traveling - the constant movement of the coach keeps the refrigerator working normally.

2. Using propane when traveling: opinions seem to be fairly evenly split on the wisdom and safety of traveling with the refrigerator operating on propane.

a. Should you feel safer with it off, the refrigerator will stay cold through the day provided you don't open it very often.

b. If you do travel with it on, please be sure to turn it off before pulling into a gas station to refuel. The open flame from the burner could ignite gas fumes.

Routine Maintenance

To ensure top performance of your refrigerator, be sure to annually clean the vent stack, the exterior coils and ensure the burner is operating cleanly. The stack and coils over time will accumulate dirt and webs. Compressed air will do be helpful for that.

The refrigerator's gas jet builds up a coating during use; that limits the amount of gas that flows. The cure is to remove the jet, soak it in solvent and then brush clean with an old tooth brush. Never use any type of metal wire to clean the jet as it will most like damage the jet.

See the references noted above for more details on how to properly accomplish these tasks.

When cleaning the interior of the fridge, you should clean the set of metal fins that sit at the upper back. Below these fins is a short removable shelf, which has a tube/vent that leads to the outside. This is where the condensation runs out of the fridge. This shelf is removable, and right where the tube attaches to the back of the fridge, there's a small catch cup; that cup may be full of goop and prevent the tray from draining properly.

Also, at least once a year, go outside and check where the fridge actually drains below the fridge. This opening has a small perforated cap and this can also get clogged with road grunge.

After cleaning both of these openings, blast a bit of canned air till the tube runs clear.

Trouble-Shooting

Won't start

Normally all you do is turn the refrigerator ON, and it selects the mode. If it sees 120VAC, that's what it'll use. If no 120VAC and if the engine isn't running, then LP. If no 120VAC AND engine running, then 12VDC.

Note: It calls for a charged 12VDC battery supply to be able to make these decisions and select a mode of operation. Battery weak or bad connections, fridge won't operate properly. There IS a "lockout mode" where it'll cool on LP if started on LP and battery power fails. It'll cool to below freezing or the LP runs out, whichever comes first.

Cools poorly when running on propane

According to information in "The RV Repair and Maintenance Manual", these are the probable causes of insufficient cooling when on LPG:

- Restricted air circulation over cooling unit.

- Refrigerator not level.

- Insufficient LP gas.

- Feeler point of thermocouple flame-failure device not heated enough by flame.

- Clogged bypass screw, clogged burner head, clogged burner-jet orifice.

- Flue baffle not inserted into central tube of cooling unit.

- Baffle too low in flue.

- Loose burner assembly.

- Improper thermostat setting.

- Failed cooling unit.

- The gas jet may need cleaning:

Remove the jet and wash it in alcohol (using a old toothbrush to scrub the inside of the jet) . Blow it out with compressed air and reinstall. Never use anything metallic ( wire for example) to clean the hole in the jet. This could alter the shape and size of the hole. This information should be in the owners manual. The flue may need occasional cleaning also.

The hard part of cleaning the jet is getting it out. I use a small wrench, from a set of 'ignition wrenches', bought at Sears, to unscrew and to replace the jets. Each model of refrigerator is a little different, so I cannot say what tool to use to remove yours.

- The thermocouple may need adjustment or replacement:

Looking closely at the spark during re-ignition, I saw that it was arcing to the tip of the thermocouple instead of the burner tube as it should have been. I replaced the thermocouple because the tip where the spark was hitting was badly corroded and I suspected damage to the thermocouple itself. Next, I adjusted the position of the mount of a new ignition probe so that the probe arced to slotted area on top of the burner tube. (I had to replace the original ignition probe because I snapped its tip off when I stupidly tried to bend the tip itself rather than adjust its base as required.) The check-light-on problem went away and the refrigerator has been working properly ever since.

Won’t operate on propane:

1. I replaced the circuit card and wiring harness with Dometic replacements and the problem has been fixed and has stayed that way. If I remember correctly, the circuit card cost me about $115 and the wiring harness $25. Dinosaur Electronics makes replacement boards for Dometic units. I've read some opinions that they're better than Dometic's with a longer warranty but don't have any personal experience with them. http://www.dinosaurelectronics.com/

2. When you have the cover off, at the right of the refrigerator compartment, you will see a small metal wire that is held over the burner. It has to be EXACTLY the right distance from the flame or it will not let the burner stay on. Try moving it a little closer or father away and see if that allows the refrigerator to stay on.

 

Won’t cool properly when underway:

The baffle that is on the top of the unit near the roof is an add-on to the baffle dometic uses. Its purpose is to prevent the blowout of the flame on the gas heater at the base of the cooling unit flue. Check to ensure your baffle is installed. Additionally, the placement of the fridge on an MB is such that an "air dam" is generated when you're moving at speed. This prevents easy flow of cooling air by the cooling coils/fins on the back of the fridge making the cooling unit less effective.

The solution may be to install a vent exhaust fan just under the roof vent cover. The fan is controlled by a thermostatic switch mounted on the chimney below where the electric heater is. The idea is to run the fan only when the chimney is hot. You can add an On/Off switch in series with the wiring so as to turn it all off and conserve the house battery when stationary or not moving on interstates.
Another possibility is a defective thermistor - a $15 part. 

Won’t operate on propane unless warmed up on AC first:

1. , The problem is probably a cracked ceramic rod surrounding the igniter wire. You can test this by removing the burner cover on the far right of the exterior refrigerator compartment, depressing the refrigerator start button, and immediately attempting to light the burner with a match. If the burner lights, let it run for a minute or so, and blow out the flame. If the igniter now (automatically) restarts the flame, then your problem is almost certainly a hairline crack in the ceramic rod, and the igniter should be replaced. Easy to do yourself, one screw and one connection. Take the old igniter with you (or the whole rig) to be sure you get the correct igniter. They come in many variations.

2. The easy way to do the test I am about to describe is to have the referigerator on, running on electricity. Standing at the service door of the referigerator, simply unplug the refer, and watch the ignition sequence, specifically the ignitor probe and the burner itself. Watch the sparking and make sure it is sparking to the burner and not some other metal surface. I have found several of the Dometics set incorrectly and the spark is not contacting the burner and when cold it will not start.

3. . If the thermo-couple is not in the right position the fridge will shut off after a few minutes and the indicator light will come on. Have someone turn the fridge on from inside the coach. You should be outside with the access panel removed. Use a pair of pliers or a standard head screwdriver to push the thermocouple closer to the flame. Be gentle when you bend it. After a few tries you should get it in the right position.

Fridge portion running too warm or cool

1. There in is a plastic piece (called a thermistor) on the back of the fridge hooked to a wire that runs up and down the coils on the back of the fridge. Push it up for a cooler temp and down for a warmer temperature. The plastic piece actually houses a thermistor used to regulate box temperature. Moving it up and down adjusts temperature. Here's a short article on the thermistor, with pictures.


Replacing the thermistor with third party item.

2. Low temps in the main refrigerator may be due to a dirty burner or low voltage (below 108 and you lose cooling power). That is why it is important to have that once a year check-up, and make sure they clean the burner assembly etc.

Dometic RM763: The fridge check light light will come on sometimes

Can you remove the roof vent over the fridge? If you can, you should see a wire rod hanging off the top of the stack. Stack is at the right hand side as you face the back of the fridge from outside the coach. Make a hook to pull that hook out. A sprial "deflector" should follow. Then work it up and down a few times. Knock on the stack with a screwdriver handle or something else you can reach it with. Put deflector back, hook the rod, reinstall the vent cover.

Then from the outside, you can remove the burner. It's held by a lock ring under the flame shield and maybe one more screw. Clean dirt (and all the rust that fell down!) from the burner area.

Retry the fridge. If it's still going into Check, then remove the burner assembly and flush the orifice "jewel" opening clean with alcohol and air blow it dry. Don't pass a wire through it, can distort/enlarge the precision opening.

Bins for freezer door: Here's a great way to save few bucks if you need new/extra bins for the freezer door.

Contributors: WxToad, Alex Rutchka, Larry Wade, Jim, Malcolm, Jonna Harlan, Joan Taylor, Mike Sylvester, Kurt, John Wozniak, Kate Klein, Don Malpas

Revised 22 Jul 2011

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