Dometic 3 way and stove issues.

[muttmaster]

Well, I am stumped. My three years old Dometic 2.7 cf 3 way is not working in gas mode. Works fine on 110v and actually runs well on 12v with 280 watts solar and full sun. In gas mode, which acts up occasionally but blowing air and making sure truck is level usually gets it running. Now The Check light stays on after many tries, and is not cooling at all. I have read and viewed what i could find on the RM2354, but I am almost ready to leave it with a service pro.

Now, I find my stove is not running right either. Lower flame, about a medium flame at max compared with before fridge started acting up. Are these issues related? The fridge burner gets hot , abet low blue flame, and blowing burner with air didn’t help any. Gas regulator problem? Any advise would be appreciated.

I will start shopping for a compressor fridge very soon, and I am not sure I want to leave the camper in the shop for couple of days or couple of weeks and several hundreds bucks later...

 

[Lighthawk]

Have you cleaned the burner pipe yet? I had the Dometic 3-way and took to carrying a small round wire brush (plumbing tool for copper pipe cleaning). The tiny slots get clogged and need to be cleaned periodically.

Note: I ultimately did switch to a compressor fridge, after our 3-way failed in 2016 (2008 OEM Hawk)
https://www.amazon.com/gp/product/B01I3P4IFG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I mention this because it fit in the cavity without modifying the cabinet.

 

[muttmaster]

I have not cleaned the pipe yet, but now I will. I have cleaned my water heater burner tube before and got better blue flame after cleaning and evicting the spider vagrant. The fridge burner flame looks nice and blue and was hoping blowing inside the tube with air would of helped. The flute gets hot as on 110 v or 12v, maybe hotter but the coils is cool on gas mode only. The Check light is on faintly in gas mode and so is dc light on faintly when gas mode is selected.

 

[NorCalSteve]

Also, try another propane tank, since you mentioned the stove is running strange. I have one tank that sometimes the safety system in the tank messes up and does not open properly. I have read that turning the gas on slowly, after connecting it might keep that from happening but I still get frustrated with the weird tank.

Anyways, worth a try.

Steve

 

[muttmaster]

Tried that already. The second full tank didn’t change anything.

 

[larryqp]

I don't know where you are located, but many areas of the country have mobile RV repair techs, I have used them in RV Parks in lots of places. You pay a service charge for the first visit usually, but you wouldn't have to leave your unit with a shop. I have had good experiences with them. Usually one visit to diagnose the problem, and possibly repair if no major parts are needed. Many carry common items on their truck. If they need to order parts then they setup another appointment with you when they get the parts.

Most are authorized Dometic repair techs.

 

[Old Crow]

Given the change at the stove and the fact that you've already tried another tank, I'd suspect the gas regulator. An easy first check would be to disconnect the hose from the tank and see if there's evidence of an oily or waxy liquid in the line. Lower the hose end to encourage any trapped oil to drain out of the regulator. I believe it unlikely you'll find any but it's an easy thing to check. The oily or waxy substance would be contaminants in the LPG from a bad fill, i.e., one where the equipment and procedures designed to prevent contamination from getting into your fill at the LPG station somehow failed.

If no evidence of contamination, I'd probably just replace the regulator as they're not expensive. I suppose another approach would be to try adjusting the old regulator's pressure but that really should be done while measuring the pressure and ensuring it stays within specifications.


Edited 10/3 to add: link to manuals for the RM2354 at PDX RV
.

 

[muttmaster]

Thanks OldCrow and All, after running the fridge on AC for four hours and got it cold, I switched back to propane again. The faint lights on Check and DC and Auto was still on, it the AC light. But the good news is that the fridge stayed cold last night. Apparently blowing air into burner did help. The coils are warm too now but not as warm when in AC mode.
Checked the hose and see no oil, but will give stove burner a good cleaning to see any improvement. Never could stir fry on the wimpy stove but hope it can boil water in decent time again.
Lessons learned...always carry a air chuck with the tire compressor, buy a pipe cleaner, and have backup iced water bottles when going into DVNP. Maybe carry the EU2200 next time too, just in case.
Thanks all for thoughtful advise, I still worry about the faint lights on the fridge panel but it is cooling.

 

[ardvark]

A faint light on the panel of a Dometic 3-way that has an "auto" is almost always a voltage issue and the most common issue is a power converter that is bleeding AC down the DC line. Are you running on shore power? If you are unplug and try operating on battery only. Dometic says their board can tolerate perhaps a bleed of 1-volt AC, but it can not. Even a .25 bleed down the DC line will throw the board off and keep the lights lit.

As to your propane, a drop-pressure check using a manometer will tell you immediately the status of your regulator.

Steve

 

[Old Crow]

I see page 10 of the Diagnostic Service manual describes the AC-voltage-on-the-DC-line issue and shows how to check for it at the main terminal block (with a voltmeter set to read AC volts on that DC connection)

Also- see the info on erratic operation of the fridge in the Grounds section.
.

 

[muttmaster]

Thanks Old Crow for link to Dometic diagnostic manual! I will dive into it later. It will save me loads of cash!
Steve, I have run the fridge on ac and on Honda generator and works fine. On dc, it works too. Faint light on check, auto and dc indicators only on gas mode. I will follow up on low voltage issue as you suggested thank you.

 

[muttmaster]

After reading the diagnostic manual, and followed all 9 potential causes as best as I could with limited equipment and knowledge, I may have found the culprit. The Thermocouple is reading around 13 millivolt when it should be 22-36 range. Most symptoms I have being experiencing is in section 7.3, page 20. Erratic operation is the buzz word! Ordered one Dometic 2932781012 off Amazon for $29, and hope it is the right one. If looks the same as mine...too lazy to call Dometic and wait for parts list, etc.
Thanks all again for steering me to the right direction. Saved me a few bucks for sure, and I hope it will help others in the future. Oh yes, watched Utube on the subject too...very helpful.
Also, ordered a Dometic cfx35 off EBay. I had a good excuse to get one.

 

[muttmaster]

Corrections on thermocouple, what I ordered was the electrode, not the thermocouple, apparently my model does not have a thermocouple. I will have to call Dometic to confirm. I did take the millivolt reading across j4 and j10 re page 20 of the manual section 7.3 under thermocouple.
OC, thanks for pointing out my mistake(s).
Good thing I have a compressor fridge on the way.

 

[muttmaster]

Update: fridge working fine after adjusting the level of the thermistor inside the fridge, didn’t need the electrode after all. I cleaned and blew out dust in and out of burner. Also adjusted the propane regulator two turn clockwise. It helped with the stove flame level. I know I should of adjusted it with manometer but I have a new one coming from 4WC, so I thought to experiment a bit. I told Jay from 4WC that I was at 7500 feet and he informed me the propane system usually is affected at 9000’. Suggested trying a new regulator that is set at 12” Water Columns at the factory.
I should of ordered a new pigtail too from him but later learned the 18” pigtail is “custom” made specific for 4WC. Called Fairview, GasFlo, etc. what a pain. There were a bit of oil at the end of Acme knob, nothing flowing out, just a smidget. My local propane guy said it could be from the additive that gives the gas the odor. Apparently there is a ball bearing in the pigtail that easily gets plugged by oil.
I also learned that my new Dometic CFX 35 needed a “break in” period before it can cool down to -8 F. At first, it only went down to 2*F. Called Dometic, service centers. Etc. what a pain. It is working ok now but the thermostat on the cooler may be off by 10*F. It is freezing water bottles for now over many hours. Not as fast as I had hoped. Worked better on AC than on DC.
Thanks, OldCrow again for all the sagely advise.