Dometic 2354 doesn't cool on 12V DC

[Bryan JR]

Roadtrek 2015 Chevy 170V. Dometic 2354 doesn't cool at all on 12V. Propane and 120V work fine. Any problem running it on AC mode with inverter on while driving? The AC indicator does light up on only coach battery with inverter turned on. Any chance of damaging fridge or inverter? Can alternator keep up as well as on 12 volt mode?

 

[Bud-ClassB]

Roadtrek 2015 Chevy 170V. Dometic 2354 doesn't cool at all on 12V. Propane and 120V work fine. Any problem running it on AC mode with inverter on while driving? The AC indicator does light up on only coach battery with inverter turned on. Any chance of damaging fridge or inverter? Can alternator keep up as well as on 12 volt mode?

I usually drive an 05 190P on ac with the coach batteries charging, two 100 amp agm batteries. Occasionally on propane, dc never.

 

[GallenH]

Interesting questions. I've always pondered about running on AC with an inverter when driving. Historically the 12v option on Dometic fridges never really cooled. It was only capable of "keeping" the cool. There should be separate 120v and 12v heating elements/rods in your fridge. Dometic service manuals give the resistance reading on each so you can (I have) test them to see if your 12v element is shot and needs replacing. I've also heard that it's possible to replace the 12v with a higher rated output version.

So on my older RM2310 for example, the 12v resistance should be 1.15ohms with a +/- 10%. The 12v puts out 125w and the 120v 160w. So the 120v does give you more heat. But, like I said, I believe you can upgrade the 12v one to a higher w output that might be closer to the 120v.

 

[GroupB]

I don’t think there is any damage potential in that operating mode. I consider the additional power required for the added DC-AC conversion to be negligible.

Is the refrigerator AC receptacle energized when the inverter is on? If so. thats what I would do. My guess is that the DC heater burned out.

 

[hbn7hj]

Fix it. Should be easy. AC doesn’t care where the power comes from. Will work fine.

 

[Bryan JR]

I can only get AC power by turning on the inverter, even when plugged into shore power. I was told fridge wasn't connected to inverter, but mine apparently is - indicator lights up.

By the way, what's the difference between power saver vs nonpower saver mode on inverter? Manual just recommends "non" for general use.

Also, my burners could be lit with build in piezo unit that has failed. Can that be replaced?

Thanks for all the feedback.

 

[GallenH]

Also, my burners could be lit with build in piezo unit that has failed. Can that be replaced?

Are you talking about the stove? You mention that the fridge worked fine on propane so I assume so. We just use one of those candle lighters that puts out an arc. Don't know your stove but assume the ignitor could be replaced.

 

[Bryan JR]

Dometic gave me the number for current replacement. The only one available is $510.00! I see off brand items for 135 to 175 watts. Would these work? Also, wires are same color, not black and red. I guess I could figure out leads with ohm meter, but I just want to be sure it's the right part. Thanks.

 

[GallenH]

Try this place.

https://www.mcenterprisesrvwholesale.com/dometic-refrigerator-replacement-pa

This is where I got a new thermostat for my old RM2310. I think they use the same part numbers as Dometic followed by a "MC"

 

[GallenH]

Forgot: The heater wires on my Dometic elements (12v and 120v) are both white. Not red/black. I don't believe that it makes any difference which gets connected to + or - on either 12 or 120v. If you contact them, they might give some advice as to putting a higher wattage one in.

On another note, are you still investigating a small inverter to power the fridge on AC while driving?

 

[Bryan JR]

It should do ok on the inverter. I can only get AC service throughout coach with built in inverter on, even whether plugged into shore power or not. Another commentator told me fridge was only connected directly to shore power. Previous owner must've customized wiring (thanks!). I purchased unit 3 years ago, and it was in excellent condition.

I took off lower grill, cleaned out the compartment and propane burner. The AC heater heats up, DC stays cold. Since AC wattage is comparable, I assume alternator can cover fridge and keeping coach battery charged while driving.

I don't know how to remove exhaust grill to clean flue and remove baffle. I'll be going back in if I can replace DC element. Thanks for website (and wiring clarification), looks promising.

 

[hbn7hj]

My memory says the only way to service the heating elements on an RM2354 in a Roadtrek is to remove it. Not too difficult.

Lay it face down on the bed, put in the new element and put it back. Remember to replace the insulation on the top. Very important.

 

[GallenH]

You're correct, hbn. The only way it's possible on my 97 PW is to remove the fridge. Too little access otherwise. I can't remember: did you put a higher wattage element in yours?

 

[hbn7hj]

You're correct, hbn. The only way it's possible on my 97 PW is to remove the fridge. Too little access otherwise. I can't remember: did you put a higher wattage element in yours?

Yep. 125 watt I think. Works very well. 75 watt original?

 

[Bryan JR]

I can't replace heaters without removing entire fridge? If so, I'll just stick with AC and propane. I haven't ordered replacement yet. The manual says original rated at 150 watts. All I can find is either 125, 135 or 170 watts. The Dometic referral one ($500.00) is rated at 170 watts. Apparently, higher wattage unit must not damage system. Might prefer the 135 if your 125 is adequate.

 

[hbn7hj]

Slow down. Obviously my memory is wrong. Probably I matched the wattage of the AC element. I just checked the parts manual and you are correct. I did not put an element in smaller than the AC element. This was over 10 years ago and I’m senile.

 

[hbn7hj]

Removing the fridge is not that difficult. You will have to do it eventually so get on with it. What are you gonna do when the AC element burns out?

As i remember it the only problem you will have is the front bottom attached to the floor. Could be stuck there, could be screws. Can’t remember.

Two screws in the back, propane line, AC plug, DC wires.

 

[GallenH]

I still have the original Dometic spare parts list that came with the RM2310. It lists the replacement 12v element as 125w and the AC element at 160w. But the RM2310 is a 3.0cf fridge. I would guess a larger fridge would require more robust heating elements to compensate for its size. IMO matching the AC wattage would be simpler than going through an inverter.

I agree that removing the fridge is not difficult. I've done it several times. You remove the door, take out the screws on the face of the flange and the 2 screws in the back that hold the rear feet of the fridge to the RV floor. Then there are the 2 12v wires that you disconnect and the propane line connection. You give it a push from the rear so you can grip it from inside the van but first (on mine) you have to cut the silicone sealer at the bottom of the flange near the floor.

 

[RT-NY]

Ipparently, higher wattage unit must not damage system

Are you talking about replacing the existing 12v heating element with with one of higher wattage? I don't think that would damage the fridge itself, but wouidn't you need to make sure that the existing 12v wiring (including in the fridge) can handle the higher amperage?

 

[Bryan JR]

The Dometic DC replacement they recommended is 170 watts, I'll go with the 135 watt for now. Forgot to mention, mine has a hatch that comes off. I can get to both heating elements. The 12V terminal block reads 12 volts, so it must be heating element.