refrigerator isn't cooling well

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refrigerator isn't cooling well

July 12, 2014, 01:46:35 pm

Hopefully some of you will have a suggestion for me:

My 2002 Dometic 1492 refrigerator is showing these symptoms:
-the whole unit worked normally last month though I seldom see 7 F in the freezer, though refrigerator side always has been 35 F.
-coach is always leveled for operating the refrigerator when parked.
-now cooling of the freezer is only to 20 F, refrigerator side is 65 F.
-12 and 120 volts are normal and the fuses on the controller board are OK.
-propane jet is has been soaked with alcohol and blown out.
-both electric elements show 60 ohms and draw 1.8 amps AC each.
-propane tank is full and the cook top works just fine - presume near 11" water column.
-heat from either source is felt at the bottom of the flue tube as normal.
-flame appears normal from propane and no debris is present.
-eyebrow displays all functions and it adjusts the temperature normally.
-I find no disconnected wires.
-no ammonia smell or chromate yellow powder anywhere.

So...what am I missing? Hopefully there are some unknown-to-me tests for the controller and eyebrow boards. Keeping my fingers crossed that is is not blockage of the tubes.

Jim
308-440-5154

Re: refrigerator isn't cooling well

Reply #1 – July 12, 2014, 02:21:29 pm

Jim one of the first things to do to see if the Thermister is working is dissconnect the 2 pin connector top left corner under 6 pin one on board. This will try to make the fridge into an ice box. If temps drop down then replace thermister, or try it in a different position on fins inside fridge box.
Does the fridge work ok on electric alone- try it on 120v only.
JohnH

Re: refrigerator isn't cooling well

Reply #2 – July 12, 2014, 02:50:20 pm

Last month, when my refrigerator was doing as yours is now, I called a mobile RV tech. He put his hanh on the coils on the back and told me the cooling unit was plugged up and needed replacing. I don't know what he was feeling for, but that night the refrigerator caught fire.

Unless you know for sure it is safe, SHUT IT DOWN RIGHT NOW!!!

Re: refrigerator isn't cooling well

Reply #3 – July 12, 2014, 03:01:14 pm

He was not feeling heat thru all the coils on the back.

Re: refrigerator isn't cooling well

Reply #4 – July 12, 2014, 04:42:25 pm

Jimmy, As long as no evidence of leaking coil I would look first to controls. If you feel competent to do it, bypass all controls to manually light burner, if it starts to cool then you have a control issue. There may be a fuse on the board in some models. Check all connections and clean them up.
Gary B

Re: refrigerator isn't cooling well

Reply #5 – July 12, 2014, 05:05:16 pm

Be cautious. There was no evidence of leakage on mine until the fire.

Re: refrigerator isn't cooling well

Reply #6 – July 12, 2014, 05:48:30 pm

My 02 refrig works great as long as the outside temp is below 90 // Over that and it is extremely slow to recover. Thank goodness I have one in my storage bay and use it to keep the meats, milk etc. I put in the four fans on the coil and two small self contained fans to move the air around inside, really helps. When the times comes it goes out and a Samsung home unit goes in. I will not repair a 12 year old unit.

Re: refrigerator isn't cooling well

Reply #7 – July 12, 2014, 08:25:30 pm

I think dinosaur electronics sells new better brains for these if needed.

Re: refrigerator isn't cooling well

Reply #8 – July 12, 2014, 09:54:57 pm

Quote from: Jim Frerichs – July 12, 2014, 01:46:35 pm

.............................................................................................
-coach is always leveled for operating the refrigerator when parked.
-now cooling of the freezer is only to 20 F, refrigerator side is 65 F.
-12 and 120 volts are normal and the fuses on the controller board are OK.
-no ammonia smell or chromate yellow powder anywhere.
.............................................................................................

Jim,
I agree with Gary. If it were mine, this is what I would do;

If you are level

If you have no yellow chromate showing anywhere (no leak)

If you have no ammonia odor (no leak again)

And you are still not cooling down, then you have to determine whether you have a control board problem or an absorption cooling unit problem.

First, pull the AC plug

Remove and tape the DC (+) supply lead for the control board

Open the control board cover and remove the AC heater element leads. Check element resistance. Should be 68 to 70 ohms (+/- 10%), for an NDR 1492, I believe, if it is a 250 Watt element. Your 60 ohms, depending on meter error, sounds reasonable.

Put remote reading thermometers into freezer and refrigerator (to prevent having to open doors for at least 8 hours).

With spade lugs on a power cord, plug the heating elements directly into a live AC outlet and run the unit for at least 8 hours without the control board connected.

Record the temperatures over time. With outside temps of 50 to 85°F, if the cooling unit is flowing properly, within 8 hours, the freezer should pull down to near 0°F and the refrigerator to near 32°F. If it pulls down to those temps or better, you have a control board issue/poor control ground/poor connection/failing temperature sensor/?? (Highly probable, because you are getting cooling and cooling units either flow or they don't flow. In other words, if they haven't discharged their contents, then they do not partially flow when they are level and heat energy is applied).

If the 20°F freezer and 65°F refrigerator temperatures are as low as it will achieve, you have a failed/failing cooling unit. (Not nearly as likely, because you are careful about being level and your unit shows no chromate leakage and has no ammonia smell)
Good luck,
Let us know what you determine,
Neal

Re: refrigerator isn't cooling well

Reply #9 – July 12, 2014, 10:46:20 pm

Thanks to Neal, John and others...still working at it. Thermistor seems not to be the problem. Other than bi-passing the board anyone know how directly to test the control board? Seems there should be a method to do that. Probably manufacturer's proprietary stuff...huh.

Re: refrigerator isn't cooling well

Reply #10 – July 12, 2014, 11:20:24 pm

I strongly suggest not sleeping in the coach with the refrigerator on until this problem is resolved.

Re: refrigerator isn't cooling well

Reply #11 – July 12, 2014, 11:26:55 pm

This might sound like an old wive's tale, but years ago (check the old thread) my refer started to not get cold and then stopped. It was getting either hot or cold (can't remember which) only 1/2 way down or so and then nothing. We were sitting level for a month or so.

I was not looking forward to pulling a window or windshield to replace it.

Someone told me to "burp" the refer, as, I believe, they said the ammonia was not going done the tubes and was blocking the flow and keeping the refer from working. This could have been caused by not being level for a short period of time, or something. (pink elephants?)

I tried shaking the coach, and using the air bags to make the coach dance... no joy.

I took it out for a short bumpy ride down a dirt and gravel road, and it taught her!

The refer started working again and has worked perfectly since.

And, I haven't seen the pink elephants in the coach either since.

Maybe that is not your problem, but it fixed mine. Magic?

Mike B.

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refrigerator isn't cooling well

July 12, 2014, 01:46:35 pm

Re: refrigerator isn't cooling well

Reply #1 – July 12, 2014, 02:21:29 pm

Re: refrigerator isn't cooling well

Reply #2 – July 12, 2014, 02:50:20 pm

Re: refrigerator isn't cooling well

Reply #3 – July 12, 2014, 03:01:14 pm

Re: refrigerator isn't cooling well

Reply #4 – July 12, 2014, 04:42:25 pm

Re: refrigerator isn't cooling well

Reply #5 – July 12, 2014, 05:05:16 pm

Re: refrigerator isn't cooling well

Reply #6 – July 12, 2014, 05:48:30 pm

Re: refrigerator isn't cooling well

Reply #7 – July 12, 2014, 08:25:30 pm

Re: refrigerator isn't cooling well

Reply #8 – July 12, 2014, 09:54:57 pm

Re: refrigerator isn't cooling well

Reply #9 – July 12, 2014, 10:46:20 pm

Re: refrigerator isn't cooling well

Reply #10 – July 12, 2014, 11:20:24 pm

Re: refrigerator isn't cooling well

Reply #11 – July 12, 2014, 11:26:55 pm

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