Dometic Fridge Issues

[Stevenattsu]

I keep it on shore power and it will cool for about 6-12 hours and then completely cut off. Ive replaced the heating element and thermistor and still having the same issues
Thanks for the help
Steven

 

[DonTom]

I keep it on shore power and it will cool for about 6-12 hours and then completely cut off. Ive replaced the heating element and thermistor and still having the same issues
Thanks for the help
Steven

Welcome! I see that is your first post here.

When it stops working, do you still have 120 VAC going to the heating element?

Does it work okay on propane?

-Don- Borrego Springs, CA

 

[Stevenattsu]

Welcome! I see that is your first post here.

When it stops working, do you still have 120 VAC going to the heating element?

Does it work okay on propane?

-Don- Borrego Springs, CA

Its runs off of propane. When it stops I repress the button and it will start cooling again and a few hrs it will kick back off

 

[Rene T]

Welcome. Can you give us the model number?

 

[DonTom]

Its runs off of propane. When it stops I repress the button and it will start cooling again and a few hrs it will kick back off

I take it you have it in "auto" and it works for a few hours and then shuts off but will not go back to propane. Is that correct? That seems to rule out it being a problem with the 120 VAC input as then it would just go back to propane, and you wouldn't even notice the difference.

The time to troubleshoot it will be a after it shuts off by itself. I would test for where the 120 VAC is lost to the heating element. It's a very simple circuit. In the AC mode, the relay of the control board puts the 120 VAC on the heating element. Relay will be closed. If the relay opens, you're back to propane, since you're not then on propane either, it cannot be the 12 volts to the relay coil. I cannot even think what can cause such an issue, but I would start to at the terminals from the control board that supply the 120 VAC to the heating element and work back from there. Or start for the AC outlet to make sure you have the 120 VAC and work forward from there. Do all the troubleshooting after it is in the failure mode.

-Don- Borrego Springs, CA

 

[Gary RV_Wizard]

The heat element and thermister weren't really relevant to the symptoms you described, so not surprising they didn't fix anything. The possibilities are:

• The fridge is losing power (120v or 12v)
• The control board is doing something freaky, e.g. the relay for 120v opens for no good reason

At a guess, I'd say the control board gets flaky, maybe from heat build-up. Could be the 120v power relay on the board, or one of the control circuits.

As DonTom suggests, you can direct-wire 120v to the heater element and see if it continues to run without interruption.

 

[Stevenattsu]

Thanks for the pointers

 

[DonTom]

The fridge is losing power (120v or 12v)

I kinda ruled out the 12V because it works on propane, unless it is happier with less voltage on propane, which is very possible if it causes the relay to drop out. But if that happens, I think it could then still be working, but on propane. IIRC, that relay will cause it to go to propane if it gets deactivated.

If there is a flakey contact on the relay for the AC mode only, that could explain it. Relay stays closed but with poor connection. That will be no AC as well as no propane operation when "auto" is selected.

And that will show up as no 120 AC to the heating element when it fails.

Intermittent AC to the refrigerator would cause it to switch to propane--ref would still be working, but it doesn't, if I understand Stevenattsu's messages correctly.

-Don- Borrego Springs, CA

 

[Stevenattsu]

Intermittent AC to the refrigerator would cause it to switch to propane--ref would still be working, but it doesn't, if I understand Stevenattsu's messages correctly.

Correct, it isn't switching over to propane on Auto

 

[DonTom]

Correct, it isn't switching over to propane on Auto

In that case, your 12 volts could be too low to operate the refrigerator in either mode. What is your house battery voltage? Also check the DC voltage on the control board when it fails.

Too low of DC voltage will cause your problem.

-Don- Borrego Springs, CA

 

[Kirk]

Correct, it isn't switching over to propane on Auto

If you would share what model of Dometic you have, we would be able to check the service manual and possibly offer more advice.

 

[Pedro Dog]

There have been at least two instances where similar symptoms were caused by a loose 12v connection at the fuse panel. Owners would measure 12 v at the back of the fridge but when they checked the fuse panel, there was a loose connection.

 

[Rene T]

If you would share what model of Dometic you have,

I already tried that Kirk but the OP never responded.

 

[Gary RV_Wizard]

I kinda ruled out the 12V because it works on propane, unless it is happier with less voltage on propane, which is very possible if it causes the relay to drop out. But if that happens, I think it could then still be working, but on propane. IIRC, that relay will cause it to go to propane if it gets deactivated.

You are probably right about a loss of 12v, but a intermittent loss of 120v could have flaky results. Not a likley cause, but still a possibility. And if the 120v relay itself fails, or the control circuit to it fails, the controller doesn't switch to propane because it is unaware that no power is reaching the heater. The check for 120v presence is done at an earlier point in the circuit.

 

[John From Detroit]

Loss of 120 should cause switch to Propane. but if Propane fails the FAULT light will. (light that is)
However if the "Loss" is after the 120 volt "Sensor" on the control board..... Well you described it.