Dometic Fridge not working

[motc777]

Hello:

Came back from out of town, and the fridge and freezer portion were not working. Now, I do have power, in that the light comes on. Typically we run on electric power. So on electric, I do not have a check light, but when I switch to Propane (which I've never run in that mode before) the check light comes on.

I do not smell ammonia. Prior to this, I was having problems with the fins freezing up, and I think that is the sign of a bad thermistor on the fin. I have checked fuses on the front panel and the rear fridge, but none are blown.

I can tell you it looks like this may have just gone out in the last 24-48 hours because the freezer portion had frost still in it.

Do I just have a bad thermistor or what?

Model: RM2652

[motc777]

OK, still working on this issue.

Last week, the fridge, which had been off for about a week, I turned on, just on a whim to see if it would work. Note: I was testing the thermistor to see if that was the issue, so I unplugged it from the board.

For the entire weekend it stayed cold in the fridge and the freezer portion was nice and cold. However, the fins did not freeze or frost up, neither did the freezer. The fridge ran from Thursday evening until the following Tuesday and then that is when I noticed water on the fins and them not feeling as cold.

I went outside and sure enough, the heating element was not working. I tired firing on propane, and three times it tried to fire up, but would just initially catch fire on the propane coming out the pipe, but never steadily burn. I got the check light showing. This previously was not happening.

To review: I had previously replaced the heating element over the course of this thread. I have tested for voltage and things seem o.k. What's the issue? Board?

[motc777]

dougrainer wrote:

motc777 wrote:

jkwilson wrote:

motc777 wrote:
This thing ran all night long and all day long on electric. I just got home and while still cold I noticed that the pipe on the outside cover is not as hot as it was. It’s lukewarm and the coils on the back of fridge are cold. The frost on the fins has gone away too. It’s like it’s not working again.

I read that if it work son propane but not on electricity then likely it’s the element. But I literally just replaced that a few days ago. Did I get a bad element? Is there some other problem?

Turning the heat on and off is how the refrigerator controls the temperature, so if the refrigerator thinks it is cold the element may not be hot.

An easy check is to make a short cord with blade terminals on the end to apply power directly to the element. The unit will run wide open and probably ice up. If it gets really cold after a day running like that, the element and cooling unit are fine.

OK, not to be thick, but just double confirming. So when running on AC, it is normal for the heating element to cool down and warm up depending on if the fridge thinks it cold or hot?

I have a new thermistor that I haven't installed yet. Should I just go ahead and do that? Mind you, prior to all this ****, both the freezer and the fridge would ice up bad, but since replacing the heating element, hasn't happened at all.

The Thermister sends a signal to the control board when the set cold temp has been reached. The board turns off the 120 element. It also turns off the LP if on LP. When the fins start to warm up, the Thermister sends that signal to the board and the board starts the appropriate Heat source(120 or LP). A BAD Thermister will test(OHM out) correctly, so replacing is the only sure way of knowing. BUT, the standard practice for professional Technicians is to wire the 120 element DIRECT to 120 for 24 or 48 hours to get the lowest possible temp. I use a Temp LOGGER that I place in the refer. It takes temp measurements every 15 minutes. I then download the LOG and print out the graph for my use and to show the customer. VERY accurate and VERY good tool to verify operation of a Refer or AC system. Doug

PS, AS I stated earlier, you need an AMP reading multiplied by the actual LINE voltage to get the wattage. Most 120 elements are in the 325 watt range, but the spec sticker on the refer will state the Wattage required. LOW AC voltage will affect the operation on 120. Anything below 115 volts will have an adverse affect. WHAT is the line voltage at the refer?

Line voltage is 120V. Thanks for explaining things!

[dougrainer]

motc777 wrote:

jkwilson wrote:

motc777 wrote:
This thing ran all night long and all day long on electric. I just got home and while still cold I noticed that the pipe on the outside cover is not as hot as it was. It’s lukewarm and the coils on the back of fridge are cold. The frost on the fins has gone away too. It’s like it’s not working again.

I read that if it work son propane but not on electricity then likely it’s the element. But I literally just replaced that a few days ago. Did I get a bad element? Is there some other problem?

Turning the heat on and off is how the refrigerator controls the temperature, so if the refrigerator thinks it is cold the element may not be hot.

An easy check is to make a short cord with blade terminals on the end to apply power directly to the element. The unit will run wide open and probably ice up. If it gets really cold after a day running like that, the element and cooling unit are fine.

OK, not to be thick, but just double confirming. So when running on AC, it is normal for the heating element to cool down and warm up depending on if the fridge thinks it cold or hot?

I have a new thermistor that I haven't installed yet. Should I just go ahead and do that? Mind you, prior to all this ****, both the freezer and the fridge would ice up bad, but since replacing the heating element, hasn't happened at all.

The Thermister sends a signal to the control board when the set cold temp has been reached. The board turns off the 120 element. It also turns off the LP if on LP. When the fins start to warm up, the Thermister sends that signal to the board and the board starts the appropriate Heat source(120 or LP). A BAD Thermister will test(OHM out) correctly, so replacing is the only sure way of knowing. BUT, the standard practice for professional Technicians is to wire the 120 element DIRECT to 120 for 24 or 48 hours to get the lowest possible temp. I use a Temp LOGGER that I place in the refer. It takes temp measurements every 15 minutes. I then download the LOG and print out the graph for my use and to show the customer. VERY accurate and VERY good tool to verify operation of a Refer or AC system. Doug

PS, AS I stated earlier, you need an AMP reading multiplied by the actual LINE voltage to get the wattage. Most 120 elements are in the 325 watt range, but the spec sticker on the refer will state the Wattage required. LOW AC voltage will affect the operation on 120. Anything below 115 volts will have an adverse affect. WHAT is the line voltage at the refer?

[motc777]

jkwilson wrote:

motc777 wrote:
This thing ran all night long and all day long on electric. I just got home and while still cold I noticed that the pipe on the outside cover is not as hot as it was. It’s lukewarm and the coils on the back of fridge are cold. The frost on the fins has gone away too. It’s like it’s not working again.

I read that if it work son propane but not on electricity then likely it’s the element. But I literally just replaced that a few days ago. Did I get a bad element? Is there some other problem?

Turning the heat on and off is how the refrigerator controls the temperature, so if the refrigerator thinks it is cold the element may not be hot.

An easy check is to make a short cord with blade terminals on the end to apply power directly to the element. The unit will run wide open and probably ice up. If it gets really cold after a day running like that, the element and cooling unit are fine.

OK, not to be thick, but just double confirming. So when running on AC, it is normal for the heating element to cool down and warm up depending on if the fridge thinks it cold or hot?

I have a new thermistor that I haven't installed yet. Should I just go ahead and do that? Mind you, prior to all this ****, both the freezer and the fridge would ice up bad, but since replacing the heating element, hasn't happened at all.

[jkwilson]

motc777 wrote:
This thing ran all night long and all day long on electric. I just got home and while still cold I noticed that the pipe on the outside cover is not as hot as it was. It’s lukewarm and the coils on the back of fridge are cold. The frost on the fins has gone away too. It’s like it’s not working again.

I read that if it work son propane but not on electricity then likely it’s the element. But I literally just replaced that a few days ago. Did I get a bad element? Is there some other problem?

Turning the heat on and off is how the refrigerator controls the temperature, so if the refrigerator thinks it is cold the element may not be hot.

An easy check is to make a short cord with blade terminals on the end to apply power directly to the element. The unit will run wide open and probably ice up. If it gets really cold after a day running like that, the element and cooling unit are fine.

[motc777]

This thing ran all night long and all day long on electric. I just got home and while still cold I noticed that the pipe on the outside cover is not as hot as it was. It’s lukewarm and the coils on the back of fridge are cold. The frost on the fins has gone away too. It’s like it’s not working again.

I read that if it work son propane but not on electricity then likely it’s the element. But I literally just replaced that a few days ago. Did I get a bad element? Is there some other problem?

[wa8yxm]

Well. glad the "Unplug and replug" suggestion worked. Did for me and a few others (I think you are #4 or 5 on my list of re-pluggers) (I'm both 1 and 2 Fridge and engine both responded to that Repair)

Longer version. There is a virus. It first became well known back in the 80's as it killed computer after computer. It likes electrical current (low levels not amps but uA) and it thus grows on contacts. Well when it gets enough it insulates and the connection fails.. Unplug/replug scrapes it off.

On computers with edge connectors (instead of pins) you usually "Erase" the board with a pencil eraser .But just unplug and replug works.

And for the propane folks. there is a spider that likes to nest in propane jets.

[dougrainer]

motc777 wrote:
Update:

It's now 10:28PM CST. It's been running on electricity since about 4:30-5pm today. I just checked freezer. For the first time since this whole episode started, I have a cold freezer. I just moved the thermostat inside the fridge portion down about 1 hour ago to about midway, and the fridge is cold! There is even a bit of frost formed on the fins!

I'm letting it run all night, but if this works, I really would like to know why, when I replaced the element the first time, none of this was working properly? Could just simply cleaning off some electrical terminals on the back panel have done it?

Cleaning the terminals will NOT have an affect on cooling. SLIDING the Thermister ONLY changes the preset by 4 degrees MAX. So, this will not affect cooling. You will NOT see any real cold production in a few hours once it starts to get cool. It takes 24 hours for the refer to reach max cold temp. A BAD/Partially blocked cooling unit will still freeze the freezer. The SLEEVE and TUBE are the same thing. Frost on the fins indicate the fins are BELOW 32 degrees which is GOOD. Doug

[jkwilson]

motc777 wrote:
Update:


I'm letting it run all night, but if this works, I really would like to know why, when I replaced the element the first time, none of this was working properly? Could just simply cleaning off some electrical terminals on the back panel have done it?

It could, but it shouldn't. If the surface of the connectors was tarnished or dirty, the simple act of connecting and disconnecting would be enough to wipe it clean and allow contact. But in a low current circuit that is seldom a problem.

I hate it when I do something like that and it makes things start to work, because you can no longer troubleshoot and you haven't identified the cause of the problem. It may be as simple as cleaning the connector, but there may be a bad connection or sticky relay there waiting to leave you with warm beer or lemonade on a future trip.

[motc777]

Update:

It's now 10:28PM CST. It's been running on electricity since about 4:30-5pm today. I just checked freezer. For the first time since this whole episode started, I have a cold freezer. I just moved the thermostat inside the fridge portion down about 1 hour ago to about midway, and the fridge is cold! There is even a bit of frost formed on the fins!

I'm letting it run all night, but if this works, I really would like to know why, when I replaced the element the first time, none of this was working properly? Could just simply cleaning off some electrical terminals on the back panel have done it?

[motc777]

Got out the multimeter. I did the following.

- Tested for good DC voltage. Did notice on the terminals a bunch of dirt dauber nest. Cleaned that off

- verified that heating element is getting power.
- verified that inner control board is working.
- verified that outer control board is working and that all fuses were intact.
- to the guy who asked about the element. I got 39.5 ohms which I was outside when testing a bit chilly. It’s within tolerance of the manual.
- scratches my head because nothing was making sense.
- can tell you that on propane last night got freezer down to bear operating range before I ran out of propane. (Note: Missus was not happy about that.)

So finally I did what someone here suggested. I unplugged every connector on that lower control board and then hooked everything back up again and left it on electric. Within 15 minutes I grabbed that vent pipe and wow was it hot! Then I felt the coils on the back. They are starting to warm up.

Don’t know if this is fixed yet. Will report back later.

[MrWizard]

dust and spiders clog up gas orifice going to the burner

Electric heading elements will burn out and go bad etc..

I run mine in l.p. And keep the electric as emergency backup

[motc777]

jkwilson wrote:
Any chance you got the wrong element? I believe yours should measure 44ohms.

How can I measure that? I have a multimeter. Do I just need to disconnect it from the board (after turning off power) just set to low ohms, and put the leads on either wire?

Edit: Found the manual. https://www.fourwh.com/NewDometicRefrigeratorManual.pdf

[motc777]

dougrainer wrote:


NEVER a control board. All they do is switch between LP and 120 and monitor the cold for the Thermister.

Got it.

ARE you POSITIVE you put the correct wattage Heat Element in? They are not all the same. In extreme rare cases the heat element tube is not attached securely to the burner flue. NO problem on a Dometic as Dometic has 2 heat element sleeves. If you suspect this you just move the heat element to the other sleeve. To verify the Heat Element wattage you either look at its stamped display on the element or you do a AMP check. The amp check will tell you the wattage. Doug

OK, I remember removing the old element from a small tube inside the pipe. When you say sleeve, I guess I'm not understanding what you are meaning? As for the wattage, I know there is something stamped on the pipe itself, but I will have to check back to see if what they gave me from the RV place is the same as what is stamped on the pipe.