Back Again: Dometic fridge!

GallenH · 07-27-2018, 11:49 PM

Ok, so I put the Dometic 2310 back in the RV. Installed a pair of 12v computer fans to aid circulation around coils. Can't get a decent temp on propane (you might recall that I had a good test on 120v. in garage). While it was out I cleaned flue, burner tube and jet. So I took it to my (reliable in the past) RV repair place and told them the issue, asked them to run a leak down test, and test the LP pressure at the fridge port. They did that and everything checked out ok...good flame height at the burner. Then they fired it up on propane and checked it the next day. Fridge 58deg, freezer 25. Then they went back and hooked it up to 120v and ran it for a day. Fridge 38deg, freezer 5deg.

At this point they're stumped and have a call in to Dometic tech support.

Has anyone experienced something similar to this? Any ideas?

Thanks!

markopolo · 07-28-2018, 12:31 AM

Do you know if the flame was still going when they checked the temperature on day 2?

hbn7hj · 07-28-2018, 12:53 AM

Yep, did you put the 4 inches of insulation on top of the fridge when you put it back in the RV? If you did not the flame heat is directed over the fridge heating it up.

GallenH · 07-28-2018, 03:11 AM

No I don't. I can ask. Gather from your query that it's possible for the flame to have gone out? As far as I know, they ran it a day on propane after running the pressure tests. Then the next morning they took the temp readings, shut the propane off and ran it on 120v. Then checked temp the following morning.

GallenH · 07-28-2018, 03:20 AM

No. There never was any insulation above the fridge when I removed it. My cabinetry has a strip above the fridge that, when the fridge is installed, provides a pretty tight fit. There were insulation strips on the sides which I replaced in their original positions. The fridge worked fine for years before without this insulation. The master puzzle.

On the 2310 the gas passes through a manual valve which is opened when you turn the fridge to the gas position. It then passes through the thermostat. Then to the jet and finally to the burner tube. I cleaned the jet and the tube.
That seems to leave the thermostat and the gas valve. But the pressure test port is on the housing with the jet (i.e. after the valve and the thermostat).

CaDreamin · 07-28-2018, 05:00 AM

I have a Dometic fridge that is exquisitely sensitive to propane pressure. It MUST be minimum 11 WC as the test port at all times or it performs very poorly.

Some techs think that 10 WC is “good enough” and for most purposes it is. Not for this fridge.

If it performs on electric then the cooling system works. The propane mode isn’t putting as much energy into the equation.

markopolo · 07-28-2018, 12:04 PM

+1 on double checking gas pressure. There is 12" water column at the fridge in my van's test port when all other propane appliances are off. It measures 11" WC at the fridge when other propane fueled items are running.

If the flame went out overnight then that could indicate a problem with the thermocouple. It could just be the positioning of the thermocouple.

I keep thinking that your thermostat is working because of the excellent cooling in AC mode.

The flame is either full on or in bypass (like a pilot light) or off in your fridge. It does not vary other than those three. The thermostat controls the length of time at full on flame. When the set temperature is reached the flame goes to bypass mode. When cooling is required again the flame goes to full on.

As CaDreamin pointed out - The propane mode isn’t putting as much energy into the equation - for some reason. Low pressure or flame out seems like the primary causes. I don't know if the quality of the propane would affect the fridge much as we're only talking about 200 watts of heat or so to make the fridge work properly.

markopolo · 08-02-2018, 03:56 PM

Any progress Gallen?

This is one fridge problem that I'd sure like to know what the fix ends up being.

ChicagoTom · 08-08-2018, 01:29 AM

Following. Mine runs fine, but then when I go to AC and then back to Propane, it won't kick on. Propane is flowing, igniter working, but it' won't light up. Different problem than yours, because my check light comes on, but make me wonder if there is a pressure issue, because after it sits in the heat for an hour or so, it will come on once I restart it.
I keep hearing to check the propane pressure, but how do you adjust it?
Thanks

markopolo · 08-08-2018, 02:36 PM

Check out Measuring Your Gas Pressure with Homemade Manometer here: Measuring Gas Pressure with Manometer

GallenH · 08-08-2018, 09:04 PM

Here's the update: The RV repair shop, at the recommendation of Dometic, did a cleaning of the propane line from the manual shutoff thru the burner tube and that "seems" to have solved the LP problem. We'll see as we leave for Glacier on Friday. After they did that, the fridge temp went from 58deg to 38deg the next day. So we have our fingers crossed. Propane goes from the shutoff valve through the thermostat to the check port to the jet........and then into the burn tube. He said that when they took the jet off, they couldn't see daylight through the tiny hole. I had removed it, soaked it and blew it out with compressed air before going there but who knows. Will post another update when we get back from Glacier.

best.glenn

booster · 08-08-2018, 09:19 PM

What did you soak the hose in? We have seen an oily substance get into propane lines on our home gas grill and it plugs up the regulator and lays in the hose low spots giving the kine of low output that you saw. When cleaning the hose I would blow it out, but not put anything else in as i don't know if it would react with the oily stuff. I would then blow it out with compressed air and hang it vertically for a couple of days.

Propane guy says that he sees that kind of oily stuff in the hoses if the hose is left pressurized for fairly long periods, especially if he weather gets cold. He thought the hose must condense out something in the gas like the odorant and it collects in the low spots. We have been shutting off the tank after every use now, and bleeding the line pressure off, and have not had it happen again.

GallenH · 08-08-2018, 11:34 PM

The only part that I soaked was the jet/orifice and I believe that's what the shop soaked as well. The line that connects to my fridge is solid. And the pathway from the line all the way to the jet is completely solid as well. I had read that the thermostat has a small screen filter at the inlet side that sometimes gets clogged (their term is "saturated"). But my issue was that the line pressure going to the fridge and the pressure at the test port on the jet housing/body were the same. That indicates that there aren't any obstructions in either the shutoff valve or the thermostat since both lie between the line and the jet. Anyways, given the Phoenix heat I started up the fridge on electric at about 9:30 and at 3:00 had to turn down the thermostat since the fridge was already at 36deg. Pretty sure that means that the cooling unit itself isn't/wasn't at fault. Haven't tried it on 12v yet.......or propane which will be the big test.

Roadtrek Adventuous RS1 · 08-09-2018, 07:55 AM

Quote:

Originally Posted by GallenH

The only part that I soaked was the jet/orifice and I believe that's what the shop soaked as well. The line that connects to my fridge is solid. And the pathway from the line all the way to the jet is completely solid as well. I had read that the thermostat has a small screen filter at the inlet side that sometimes gets clogged (their term is "saturated"). But my issue was that the line pressure going to the fridge and the pressure at the test port on the jet housing/body were the same. That indicates that there aren't any obstructions in either the shutoff valve or the thermostat since both lie between the line and the jet. Anyways, given the Phoenix heat I started up the fridge on electric at about 9:30 and at 3:00 had to turn down the thermostat since the fridge was already at 36deg. Pretty sure that means that the cooling unit itself isn't/wasn't at fault. Haven't tried it on 12v yet.......or propane which will be the big test.

We experienced problems at high altitude.... also extreme heat.....try and park in the shade ...OR... electric or batteries with plenty of solar....

Good luck.

SteveJ · 08-09-2018, 02:44 PM

I've been been camping at altitudes up to 9600 with zero issues cooling the fridge on propane. The fridge is a RM 2451 just over a year old, used for about 8 months in that time period.

On TDY near Bayfield CO

Roadtrek Adventuous RS1 · 08-09-2018, 05:32 PM

Quote:

Originally Posted by SteveJ

I've been been camping at altitudes up to 9600 with zero issues cooling the fridge on propane. The fridge is a RM 2451 just over a year old, used for about 8 months in that time period.

On TDY near Bayfield CO

Hmm, I don't know what you did?

Dometic USA just told me that you need to be on batteries or electric above 5,500 feet..... they said that their units are NOT DESIGNED to work on propane at higher altitudes... period.

Do you have any "cooling fans" in your cabinet where the refrigerator is installed?
I just discovered that we don't... Roadtrek confirmed that they didn't install any.

Bea · 08-09-2018, 05:43 PM

Similar issue with my Dometic--worked fine on 120, but would not stay cold on LP. Extended a trip to get appt with certified Dometic service technician. He concluded that the LP regulator was the problem. Did my research, replaced it with a more reliable regulator, found the line from the LP tank to the regulator had oil in it. Once the repair was completed, all is well and we're back to dry camping.

GallenH · 08-09-2018, 09:53 PM

I'm honestly not sure about the newer Dometic models. Mine is a 2310 and it's 20 years old. No circuit board, etc. Just a piezzo lighter mechanism. This year was the first time we experienced problems. We've probably camped up around Sunrise in the AZ White Mountains a half dozen times and the altitude there is 9,000-9,500. We've never had any fridge, cooking, or heating problems on LP.

Oh, RT: Since the problem came up this year, I installed dual computer fans in the fridge compartment. Let you know how it goes after Glacier trip next week. Right now I'm sitting in PHX heat and had to turn the fridge down to 3 as the temp in the fridge had gotten into the 20s. That's off 120v.

SteveJ · 08-10-2018, 01:10 AM

Quote:

Originally Posted by Roadtrek Adventuous RS1

Hmm, I don't know what you did?

Dometic USA just told me that you need to be on batteries or electric above 5,500 feet..... they said that their units are NOT DESIGNED to work on propane at higher altitudes... period.

Do you have any "cooling fans" in your cabinet where the refrigerator is installed?
I just discovered that we don't... Roadtrek confirmed that they didn't install any.

No magic here. I do have two computer fans suspended under the top coil but only turn them on when it's over 85 or 90 out. Maybe a bit lower temp if the afternoon sun is on the fridge.

My brother joined me for a while and was having LP cooling issues with his RM2310. Turned out that there was a good size hole in the burner tube that is supposed to have just slots for the flame. That was not, however, an altitude issue, strictly outside temp dependant.

If you are having issues on propane, check the burner tube and jet. I had my burner not light because of a couple drops of rain had gotten into the tube from an hellacious thunderstorm.

jra3733 · 08-19-2018, 06:34 PM

Yes i am going through the same thing at this time.my usual reliable RV repair shop is also stumped. My first time for LP problems was in the high altitude but since then it has never worked properly on LP.Plan on calling the maker this week to get help

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