Dometic Fridge repair

[doodledee]

Hi all great helpful thread. New-to-me '87 purchased last spring, getting around to some winter projects now. Having a lot of fun learning new stuff.

** Background **
Fridge didn't work on 110 or 12V at all and want to refurb propane tank before trying propane (assumed it wouldn't work on propane either).

** What I've Done / Learned **
Pulled fridge and started walking thru that one 10 page guide for cleaning and rehabbing which is awesome and helpful.

Wiring at switch was all wrong - someone had been here before hmmm - so hooked things up according to wiring diagram. Replaced fan.

Plugged into 110 and she works!!

Started inspecting propane system ahead of deep cleaning. Noticed that the safety switch has been modified (?) and a crimp and is missing a mount for the 'flame LED' light. See pictures below.

** Questions **
Any ideas what's going on here? Is that crimp normal? Does anyone have a source for the flame LED connection (just some sort of temp sensor??).

Thanks!!

[davevickery]

[dschaftlein]

you can get a millivolt reading from the thermocouple if you unscrew the end of it from the valve. the fridge will still operate without the signal wire, your LED just wont light up. The fridge may be from an earlier model that didn't have the LED?

I have the crimp in my thermocouple. it's crimped in the same place but there are 3 smaller crimps rather then the 1 long crimp.

[doodledee]

Thank you both for the reply an information. I will get to work rehabbing the propane system on the fridge see if it lights.

Will also report back on ability to measure mv on thermocouple as well.

Reasonably cool/cold beer on deck for next summer!!

[jseehorn]

After reading many posts here and with the advice of others I set out to improve the performance of my Dometic RM182B. Here are my results: Before I had an unscientific temp differential from inside the fridge at the floor to outside the fridge of approx. 20 degrees F (uncontrolled camping environment) and now am achieving 42.3 degrees F differential after running it over night in my garage (more controlled environment). Current temps are 70.3 degrees F room temp, 20.3 degrees F internal aluminum cold plate temp and 28.0 degrees F at the floor inside the fridge after running for 14 hours undisturbed. Changes made were: cleaning the gas jet, fire box and flue, replaced external fan with two quieter fans with higher combined flow, added two small internal fans, two additional selectable fan thermo switches of lower temp values, new flame indicator LED (bright blue), insulated the exhaust flue and part of the fire box, added heat shielding to separate the hot flue section from the cooling fins on the rear of the fridge, new piezo igniter, enlarged the air pump exhaust port slightly, added an air check valve on the air pump along with cleaning, adjusting and lubricating it, cleaned the contacts on the power select switch along with new unmelted connectors, and adjusted the sight glass light tube so I can now see the flame and sometimes the spark. So far I am very pleased with the results. One of the more notable observations is the exhaust flue temp on the side of the van. Before it was only warm to the touch (approx. 100 degrees F) now it is running at 131 degrees F. Thanks to everyone that posts here with your tips and results, I hope this helps.

[jerrydog411]

Nicely done John!

[VicVan]

Nicely done. These are great fridges! Thanks for the pics, too.
_________________
'90 Little Blue Truck, 2WD auto, FAS GenV 2.0 NA (AVH)

[Ahwahnee]

Great idea - I'll try the insulation 'next time'.

[dionski]

Lot's of great tips. Couple of questions I haven't been able to find the answers for...

When bench testing the RM 128B, where do I attach the leads from the 12V battery? Do I need the 12V battery when I'm testing in the 110V mode? I get how the cooling takes place in the gas mode but am unclear with the process in the 110Vac or 12Vdc modes. Is there an electric heater somewhere that heats the refrigerant? Any other tips on bench testing? Thanks!

[crazyvwvanman]

Yes, it uses heat in each of the 3 modes. There is a 12 volt heater coil and a 110v heater coil.
The fan on the back is 12 volt only so whatever mode you are running it in you would also need 12 volts for the fan to work.

There is a 3 pin connector the fridge uses for the 12 volt connections.
On this wiring diagram from the gallery it is labeled connector T3a, pins 1,2,3
In bottom left it tells what each of the 3 pins is meant to connect to.

Mark

[rkoss]

Good thread, I had the notion of finding an auto igniter and adding it to my super classic fridge in my 1980, this thread inspired me to actually do it. Robbed the igniter from a 91 fridge and got it working. Slick upgrade. But a few questions that may help me improve things more that hopefully someone with better understanding of the wiring can help with. I spliced the high voltage lead into the connector for the stock piezo igniter so I have both manual and auto options. Everything functions well and as intended!

Right now I have a on/off push button switch wired inline on the igniters constant power supply. I did this to be able to turn it off as unforeseen issue may have come up once I put it all back together. My biggest question is what happens if the propane runs out and the igniter is on... will it just click away until I notice it? Can they run for hours on end or will they fail pretty quick? I noticed that the power source came from a much more involved switch system on the 91 model than what mine has and I am wondering if there was something built into it that switch that didnt supply the igniter with power when it detected low pressure from propane.

I also added a small CPU fan inside the fridge on top of the fins for some air circulation. This is currently switch controlled. I was trying to figure out how to get it to be controlled by the thermostat so that it only ran when the saturation process was functioning. After a few hours of google searches and touching terminals systematically with the multi meter, I came up inconclusive and left the toggle switch in place to control it. Anyone have thoughts on where to get a power source controlled by the function of the thermostat (I am not talking about the snap disc one for the rear fan controller, I am talking about the one for controlling 120V and gas temperatures inside the fridge).

[Vanagon Nut]

[Franklinstower]

while I got all my cabinets out, I decided to check fridge operations for two different fridges I have.

My spare was giving to me by a friend that went to a truck fridge. I cleaned the jet and fire box. Here is the flame I am getting:

not a solid blue throughout (sight glass view) so, is that not an efficient burn? Could it also be because I am using the bbq regulator and not the vanagon Regulator? Any thoughts appreciated.

Update: Flame is fine, the color was just due to the piezo thingy in the flame. I got a better angle on the flame with a mirror and it looks good. Temp in the fridge went from 54 to 22 in under 2 hours. even with no fan on the condenser fins.

Thanks,
Paul
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug

[rkoss]

[quote="Vanagon Nut"]

[Vanagon Nut]

[Abscate]

If this is the same company in OH that makes marine stuff I can tell you the are top shelf on customer support on their stuff

Don’t be afraid to call them with questions.
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.ssS!

[mrshrimp]

One thing that helps a lot is too add a fan inside to blow over the cold plate and prevents ice buildup, move the cold air around. This is especially helpful when fridge is packed.

[colins84]

Recently on a trip, my alternator’s voltage regulator failed. Before this, my Dometic 182b has run perfectly in all 3 modes. Since the alternator failure and replacement, the fridge will not keep cold on 12V.

I Removed the fridge, found that the connectors on the selector switch were quite melted, so I re-terminated all connections, and put a new switch in. (Although, every wire and the switch had good continuity)

The other symptom I’m finding is that, even after the switch replacement, the control panel feels very warm (especially at the switch) while running the fridge on 12V. I suspect that the failed voltage regulator ruined my 12V burner coils?

Does anyone have any experience replacing the 12V burner coil?

Any other thoughts of what might be going on?
_________________
1985 Vanagon Westfalia (Subaru EJ25 w/ Peloquin)
1986 Vanagon GL (2.2L)

[colins84]

Continued troubleshooting: I metered the 12v coming into the fridge under the sink. Both the hots metered at 13v (one constant, and one only when keyed, per the relay)

I then checked continuity on the 12v burner coil. Continuity was weird. Started really high, and the steadied out to 1.9. I decided to pull the fridge and try replacing the 12v burner coil, as it’s the last thing in the 12v fridge system that I could think would be causing the control switch to get warm.

Also, while the fridge is switched to 12v, and the van running, voltage on my house battery drops quite quickly. Say, if I started at 14v and switched the fridge to 12v mode, drove for 30 minutes, the voltage will finish at 13.2. And the fridge hasn’t kept its coldness.

Please throw a dart in the board for me! Could it be my relay under the driver seat? Maybe that shorted when my voltage regulator on the alternator failed? I am running a GoWesty dual battery setup. Maybe my thermostat control has failed?
_________________
1985 Vanagon Westfalia (Subaru EJ25 w/ Peloquin)
1986 Vanagon GL (2.2L)

[crazyvwvanman]

A lack of cooling in 12v mode can't be caused by the thermostat.
The thermostat isn't used in any way while while running in 12v mode.

Mark