Dometic 2-Way Fridge Not Working on LP

[Edutater]

Prior to a recent trip, I hooked our 16' Bambi to shore power to cool off the Dometic 2-way fridge before we departed. Then, I switched it to gas as we were leaving. Got to the destination and found the ice in the freezer had begun to melt. Upon investigation, it was clear the LP function was not working. And, when switching from "Auto" to "Gas" mode, I noticed that I wasn't hearing the clicking sound of the system trying to ignite the LP gas. Thoughts or suggestions would be appreciated.

[dlkershaw]

Having used a 3 way fridge for 10 years in our Bambi 22fb. I found it took a number of try’s to get the fridge to light. We were always stationary when the fridge was lit. Gas flow always seemed to be an issue. Try lighting the stove before you start your trip. Light the stove to make sure your gas is flowing. It does take about 5 minutes for the fridge to light, make sure your 12 volt battery system is turned on ( for the igniter to activate.)
Also make sure you have turned your propane on and switched the fridge console to propane.
Best of luck, the propane option is very efficient.

[arvaterry]

Sometimes you have to get to where the gas pilot light is and adjusted a bit so that there is more oxygen. This becomes more of an issue with altitude. the pilot light is on the outside you open the hatch and you can adjust it open more air to the gas line which may help as well.

[waninae39]

2 way fridges use 12v dc or 120v ac
3 way add lp

as no longer uses 3 way fridges do to the fire risk and other financial reasons

[Al and Missy]

Originally Posted by waninae39

2 way fridges use 12v dc or 120v ac
3 way add lp

as no longer uses 3 way fridges do to the fire risk and other financial reasons

My fridge is 120 VAC and propane. I believe that is the classical definition of 2-way and 3 way fridges additionally operate from 12 volts DC.

[Al and Missy]

Originally Posted by Edutater

Prior to a recent trip, I hooked our 16' Bambi to shore power to cool off the Dometic 2-way fridge before we departed. Then, I switched it to gas as we were leaving. Got to the destination and found the ice in the freezer had begun to melt. Upon investigation, it was clear the LP function was not working. And, when switching from "Auto" to "Gas" mode, I noticed that I wasn't hearing the clicking sound of the system trying to ignite the LP gas. Thoughts or suggestions would be appreciated.

When set for propane, first you should hear a "clunk" as the controller turns on the valve that allows gas to flow. Then you should hear a repetitive soft clicking sound as the ignition tries to light the flame. The fridge requires 12 volts DC to operate on shore power, so you should have 12 volts to operate the gas valve and the ignition. If you don't hear the gas valve, locate it and see if there is voltage to it immediately after turning the fridge on. If there is voltage but gas is not flowing, the valve may be bad. IF you hear the gas valve and not the ignition clicking, the igniter (spark plug) may have a bad connection or it may be bad. There could also be a spider nest or something shorting it out so the spark doesn't happen. On some models the spark coil is a separate part. IF there is no spark and the igniter looks OK either the coil or controller board may be bad.

[richard5933]

There are some great YouTube videos about diagnosing an absorption fridge. These will take you through the steps to make sure that the various connections and controls on the rear of the fridge are functioning properly.

This could be due to lack of 12vdc power, a bad control board, a loose connection, out of gas, etc.

Are you sure that you have gas and that it's working on the stove top?

[uncle_bob]

Hi

+1

If this is the first trip of the year and propane has been shut off .... I'd check the stove first. If there's no propane there, the fridge is not going to be happy.

With "no clicking" you may well have something more complicated going on.

Bob

[EEC]

Originally Posted by uncle_bob

Hi

+1

If this is the first trip of the year and propane has been shut off .... I'd check the stove first. If there's no propane there, the fridge is not going to be happy.

With "no clicking" you may well have something more complicated going on.

Bob

Sorry for what you’ll be rolling your eyes with this post.

If the fridge starts up immediately when shore power is applied (ie, causing ignition of the gas and application of 12v DC) the control board is then in “auto” mode. But It doesn’t automatically go to gas when shore power is disconnected? Seems like”auto “ would keep it going because the gas valve is already open, 12v is applied, and the burner is operating. So “auto “, at least in my case, doesn’t mean automatically.?
To keep it running the gas button must be engaged before disconnecting shore power?
Because disconnecting shore power shuts down the fridge and I can’t restart. So I must have a problem with the gas valve, spark plug or board? No, I don’t hear any “clunk” or “clicking “
Thanks for your understanding.

[aftermath]

Originally Posted by EEC

Sorry for what you’ll be rolling your eyes with this post.

If the fridge starts up immediately when shore power is applied (ie, causing ignition of the gas and application of 12v DC) the control board is then in “auto” mode. But It doesn’t automatically go to gas when shore power is disconnected? Seems like”auto “ would keep it going because the gas valve is already open, 12v is applied, and the burner is operating. So “auto “, at least in my case, doesn’t mean automatically.?
To keep it running the gas button must be engaged before disconnecting shore power?
Because disconnecting shore power shuts down the fridge and I can’t restart. So I must have a problem with the gas valve, spark plug or board? No, I don’t hear any “clunk” or “clicking “
Thanks for your understanding.

I am a bit confused by this post. First of all, I have a 2006 trailer so things might have been very different in 2004. When plugged in and running on AC, the gas is not involved. The heat needed is provided by an electric element. When the AC is disconnected the propane provides a small flame to provide the heat. And NO, the gas button does not have to be engaged before disconnecting shore power.
The Auto feature senses when shore power is available and automatically changes from gas to AC. When AC is disconnected it automatically changes over to propane. It is a very dependable system and mine continues to work after 16 years.
When changing back to gas I hear a clicking sound as the gas is ignited. After a few trials it shuts down and a warning check light comes on. I turn it off, then back on again and it has always ignited. If there is no clicking sound I am guessing that you need to look at the electronics. Connections? A problematic board?
They changed over to 12v fridges for a lot of good reasons. They are much more dependable and do better when it is very hot outside. They also provide more space inside the box. But, they depend on more electricity so you will need better batteries and a solar array will also come in handy. So far, my absorption unit works well, draws very little current and I can boondock for long periods of time with cold beer at the ready.

[Andy543]

Tiny spiders can get into the burner tube and foul the gas flow. Happened to me.

[uncle_bob]

Originally Posted by EEC

Sorry for what you’ll be rolling your eyes with this post.

If the fridge starts up immediately when shore power is applied (ie, causing ignition of the gas and application of 12v DC) the control board is then in “auto” mode. But It doesn’t automatically go to gas when shore power is disconnected? Seems like”auto “ would keep it going because the gas valve is already open, 12v is applied, and the burner is operating. So “auto “, at least in my case, doesn’t mean automatically.?
To keep it running the gas button must be engaged before disconnecting shore power?
Because disconnecting shore power shuts down the fridge and I can’t restart. So I must have a problem with the gas valve, spark plug or board? No, I don’t hear any “clunk” or “clicking “
Thanks for your understanding.

Hi

As noted above:

Gas is not involved at all when you are on shore power. The fridge pulls about 2A off of the 120V circuit to do what it needs to do. It also pulls about 1A off of 12V to run the control board. You can pull the propane tanks and take them to be refilled. The fridge will still keep going on shore power.

If you are running off of a generator, the 2A that the fridge pulls may not be a load you want to have on the generator. You would set the fridge to only run on LP. That it would not load the generator.

With a properly functioning control board, "Auto" means switch to shore if it't there. In auto if you are on propane, the gas will shut down when shore power is connected. It will turn back on again when shore power goes away.

The cycle between gas and shore is no different than turning the fridge on or off. If you are on propane, the click click click of the igniter should be very obvious.

Bob

[EEC]

Thank you Bob and Aftermath,
I can see why Aftermath was confused by my post - because I totally did not understand the process. I didn’t realize that shore power was acting as the heat source, no propane involved. I mistakenly thought the shore power was igniting the propane So like the OP I must have gas valve or igniter or maybe control board failure. Or maybe a spider web. I’m on the road now at Monument Valley at a campsite with shore power and will dig into the propane ignition problem during the weekend.
As an alternative, without shore power, I can use my Bluetti power supply’s TT30 receptacle and run the shore cable out the back emergency window to make the connection. Not on the road of course.
Sorry I should have simply asked: how does shore power 120v, 12v DC, and propane run the refrigerator.
Thank you all for taking the time for what I should have known.

[uncle_bob]

Originally Posted by EEC

Thank you Bob and Aftermath,
I can see why Aftermath was confused by my post - because I totally did not understand the process. I didn’t realize that shore power was acting as the heat source, no propane involved. I mistakenly thought the shore power was igniting the propane So like the OP I must have gas valve or igniter or maybe control board failure. Or maybe a spider web. I’m on the road now at Monument Valley at a campsite with shore power and will dig into the propane ignition problem during the weekend.
As an alternative, without shore power, I can use my Bluetti power supply’s TT30 receptacle and run the shore cable out the back emergency window to make the connection. Not on the road of course.
Sorry I should have simply asked: how does shore power 120v, 12v DC, and propane run the refrigerator.
Thank you all for taking the time for what I should have known.

Hi

These fridges pull a lot of power running on 120V. We usually talk about current at 12V so it can easily get missed. Best guess is it's pulling about 2A at 120V. That's 20A at 12V with 100% efficiency. If it was running all the time, you would blow through 480AH in a day. Even if it only runs 1/3 of the time that would be 160AH.

Best to get things fixed.

Bob

[Sunny Falls]

In case you were not aware, Dometic is discontinuing manufacturing absorption refrigerators:

https://www.fiberglassrv.com/forums/...ed-103650.html

Gayle & Bob
"Los Gatos Casita"

[richard5933]

Originally Posted by Sunny Falls

In case you were not aware, Dometic is discontinuing manufacturing absorption refrigerators:

https://www.fiberglassrv.com/forums/...ed-103650.html

Gayle & Bob
"Los Gatos Casita"

This may be true, but Vitrifrigo still makes them and the Amish outfits still produce replacement cooling units for many (most?) models.

[richard5933]

Originally Posted by EEC

.... Sorry I should have simply asked: how does shore power 120v, 12v DC, and propane run the refrigerator...

For those that missed it, an absorption fridge needs a heat source to make cold. There are three possible options:

1) A gas flame (this is the propane option). It's the most efficient way to run the fridge.

2) A 120vac heating element in the chimney above the propane flame. Works well but not as efficient as the propane.

3) A 12vdc heating element (not all fridges have this 3-way option). This works but is a huge drain on batteries and really only useful if you have great on the road charging from the TV.

[AlbertF]

Originally Posted by Al and Missy

My fridge is 120 VAC and propane. I believe that is the classical definition of 2-way and 3 way fridges additionally operate from 12 volts DC.

Agreed. Our trailer has a 3 way - propane, 120V AC, 12V DC. I need to replace the propane burner (it keeps going out and relighting every couple of seconds and appears to be damaged), so we've been using the 12V option while travelling.

The 12V setting works well, but current draw (AFAIK) is about 7.5 amps vs about 4.4 for a comparable 12V DC compressor refrigerator. With 120 Ah usable battery, we are theoretically good for up to about 16 hours this way.

[richard5933]

Originally Posted by AlbertF

Agreed. Our trailer has a 3 way - propane, 120V AC, 12V DC. I need to replace the propane burner (it keeps going out and relighting every couple of seconds and appears to be damaged), so we've been using the 12V option while travelling.

The 12V setting works well, but current draw (AFAIK) is about 7.5 amps vs about 4.4 for a comparable 12V DC compressor refrigerator. With 120 Ah usable battery, we are theoretically good for up to about 16 hours this way.

Have you tried to clean and adjust the burner? (Don't use anything to poke the opening - it's easily damage)

Lot's of good videos online about how to clean it.

Also, if the chimney is dirty/clogged/obstructed in any way the burner won't operate properly. They sell a special long flexible brush for this but you can use makeshift devices as well. Not hard to do but well worth the time. Even if you end up buying a new burner, you'll still want to clean the chimney.

[AlbertF]

Originally Posted by richard5933

Have you tried to clean and adjust the burner? (Don't use anything to poke the opening - it's easily damage)

Lot's of good videos online about how to clean it.

Also, if the chimney is dirty/clogged/obstructed in any way the burner won't operate properly. They sell a special long flexible brush for this but you can use makeshift devices as well. Not hard to do but well worth the time. Even if you end up buying a new burner, you'll still want to clean the chimney.

I tried cleaning, but without understanding what I was doing, and away from home without supplies. I'm not sure if the burner was failing, or I ruined it, but the "vent" does not seem to be flowing gas properly, and the flame keeps going out. However, I have a new burner assembly now (over $300 CDN from the dealer!). We have the RM 8050 refrigerator; burner, thermocouple, etc. is one assembly. I haven't seen a video for this style of burner - it looks like this: https://www.ebay.ca/itm/164670826843

I appreciate the comment about cleaning the chimney - thank you! I'm hoping to install it on Saturday.