Fridge not cooling

[rstews]

Hi,

Last trip out our fridge stopped cooling. I've checked other users queries and this is what I know. Dometic RM 2652 in 2006 trailer. I assume it's original. The thermistor read about 2k ohms in 90 degree weather but went up to near 9K ohm in ice water. In gas mode the flame lights and stays on. In electric mode the element pulls 2.78 amps which matches the 44 ohm element. It switches between modes properly. The chimney gets hot and the lower pipe into the cooling unit gets warm, I can keep my hand on it. Feels like near ambient temp on the upper pipes out of the cooling unit. I've never smelled ammonia inside and don't see any green residue outside with the unit still in place. The lights on the front panel all work as well as the interior lamp. I've downloaded the service manual as suggested. I've also removed all power from the board to do a hard reset. The two fuses on the control board are good. The vent seems to be clear.

 Now what? Is the purpose of the control board to turn on the heater as needed? If so I guess it's working. Could I have a leak up high on the coils that I can't see yet? Any way to test ammonia level?

Thanks,

Randy

[griffy]

Does your freezer maintain normal temperatures but the refrigerator doesn't cool? If so, disconnect the thermistor from the control panel and see if your refrigerator gets cold overnight.

[rstews]

Nothing cools, fridge nor freezer

[sundancer268]

Sounds like the cooling unit went south on you.  There is no way the owner can check the refrigerant level that I know of and I don't know of any RV Service Departments that can either.  They will want to sell you a new reefer or a cooling unit.  You can purchase a cooling unit yourself and install it if you are handy and physically able.  I would not go with a unit made by the manufacturer anymore.  The units made before the turn of the century were better built in my opinion than the 21st century units.  I have a unit in my Motor home from 95 and other than the control board failing shortly after I purchased the unit used, I have had no problems.  I installed a used unit from a salvage yard in my 1984 Travel Trailer and it also works good.  I believe it is a early 90s unit.  One is a Norcold and the other is a Dometic.  As long as the units are operated only when level or in motion, they should work almost forever as there are no moving parts to wear out.

[Dutch_12078]

Most likely the sodium chromate rust inhibitor in the ammonia/hydrogen mix has crystallized and plugged the tubing due to off level operation and/or overheating. There is no repair possible in that case, and the cooling unit needs to be replaced. If your RV usage is primarily in campgrounds with electric hookups, a residential fridge replacement may be the most economical way to go. Depending on the dimensions of your current fridge, there may be a residential model that's a near perfect fit in the opening.

Edited August 1, 2020 by Dutch_12078

[richfaa]

Sounds like the cooling unit ours did the same. The Amish cooing unit from Indiana is far superior to the OEM unit  our ESP plan covered the cost of replacement.

[rstews]

1 hour ago, richfaa said:

Sounds like the cooling unit ours did the same. The Amish cooing unit from Indiana is far superior to the OEM unit  our ESP plan covered the cost of replacement.

Thanks. I was just looking at RV Cooling Unit Warehouse that claims to sell the Amish units. Is this the same place you're talking about and if not do you have contact info?

Randy

[Kirk W]

No matter what cooling unit you choose to use if you do replace it, before you do so take the time to read this article about the RV-ARP devices and how they work. I would not operate an RV type refrigerator without one. 

[rstews]

Thanks for the replies! I ordered a new, not remanufactured, unit from RV Cooling Unit Warehouse. Now comes the fun part. Need to trick that strong friend to show up to my house.

Randy

[TXiceman]

When installing the new cooling unit in the old cabinet, be sure and get the unit well sealed to the cabinet.  Any moisture leakage will cause the unit to load up with moisture and ruin the insulation.

Ken

[rstews]

1 hour ago, TXiceman said:

When installing the new cooling unit in the old cabinet, be sure and get the unit well sealed to the cabinet.  Any moisture leakage will cause the unit to load up with moisture and ruin the insulation.

Ken

Thanks, Ken. Will do

Randy

[oldjohnt]

Ive seen a few You Tube videos showing cooling unit replacements, looks like a job I would NOT enjoy lol

 Good luck with it 

John T

[richfaa]

14 hours ago, rstews said:

Thanks for the replies! I ordered a new, not remanufactured, unit from RV Cooling Unit Warehouse. Now comes the fun part. Need to trick that strong friend to show up to my house.

Randy

Yes that is were we got both of our replacement units never another problem.

 

[bobsallyh]

I have replaced two cooling units over the years. Not that bad of a job. What we did was put our coffee table covered with a piece of carpet at the bottom of the refer cabinet, slid the refer out of the hole standing it on the coffee table. Then we laid it door down on the table after removing what needed to be done in the cold box and freezer. As per instructions just followed thru. One thing I distinctly remember was the prying loose of the old coil. Thought that was the end of the reefer. But followed thru and everything went according "to Hoyle" even though "Hoyle" wasn't there. Slid back in the hole connected everything, vacuumed up the floor and within several hours it started cooling down. 

[rstews]

6 hours ago, bobsallyh said:

I have replaced two cooling units over the years. Not that bad of a job. What we did was put our coffee table covered with a piece of carpet at the bottom of the refer cabinet, slid the refer out of the hole standing it on the coffee table. Then we laid it door down on the table after removing what needed to be done in the cold box and freezer. As per instructions just followed thru. One thing I distinctly remember was the prying loose of the old coil. Thought that was the end of the reefer. But followed thru and everything went according "to Hoyle" even though "Hoyle" wasn't there. Slid back in the hole connected everything, vacuumed up the floor and within several hours it started cooling down. 

Thanks. Was trying to think of something to slide it out on. I'll see if I have a table the right height.

Randy

[rstews]

Just an update. Got the new unit installed a few weeks ago and went on a few trips. Fridge is now cooling great. Even had ice start to form on cooling fins so can't ask for much more. Did have to straighten out the frame a bit from shipping but sounds like that is common. Other thing was I couldn't get my trailer's outside cover on. Needed to remove the gas burner mount and cut 1" off then weld it back together and good to go. Thanks for all the help. It's nice when you have to make a large money investment when troubleshooting to have someone else agree with your diagnostics.

Randy

[Kirk W]

Thanks for coming back to let us know! Now tip a cool one for me.  😊