Older fridge cooling Better on 110 than propane

[Buffblazer]

Hello all, hoping for some help before my 4th of July trip

I took my 98 Lightcraft truck camper up the mountain this last Friday and when I left the house with the fridge on 110 the temp was 28 degrees.

Switched over to propane and drove an hour to my spot to find the fridge at 55 degrees. Could not get it to cool down.

Yesterday I ran it on 110 to verify it wasn’t the cooling unit. I had a tall blue flame but went ahead and cleaned the burner unit and blew out the area. Still the same height flame.

I adjusted my settings from hi-med-low and see very minimal flame height change and have never heard the propane “roar” that people talk about in the 2 years I have owned it. I did replace my regulator last year and have no issues with my stove or heater working.

Any suggestions? Not sure of the brand of fridge. It’s the old school 3 way with the turn knob in the back and the green 110 switch and red 12v

Thank you

[NRALIFR]

Ernie, where’s the refer’s top vent on your RV? Roof or sidewall?

If it’s in the sidewall, that’s essentially the same as a refer installed in a slideout.

Either way though, you should get the installers guide for your fridge, and compare the clearances, insulation, and air baffles with your install.

:):)

[dougrainer]

ernie1 wrote:
dougrainer: Neither of my friends nor I have slides in our rvs and since we have identical problems common to two different models of new Dometic fridge in that the fridges work fine on ac but poorly on propane I'm certain that the issue is propane related and less an improper installation. Question is, what to look for that the rv repair shops in conjunction with Dometic techs can't resolve. I think Dometic has flaked on this issue. My thinking is either an undersized gas jet, a crimp or restriction somewhere in the gas supply system (which might be a Dometic design issue). Gonna check the gas supply pressure and, if less than 11.5, adjust the regulator accordingly. Can't get any info on the proper jet size nor availability because Dometic says they can't give that info out nor can they give any references probably due to a liability issue. So Doug, what do you think?

What do YOU think the odds are that all your friends would have a Jet issue on the 8555 that were probably built months or years apart at Dometic? ALL in your circle of friends. Nobody else including me that has worked on thousands of RV refers over the years has experienced such a problem. MOST operational problems ARE caused by the OEM install. The refer is just an appliance and relies on correct 120 voltage and LP pressure. Nothing else that would be Dometic's fault. You want to blame Dometic. Understandable. BUT, My experience shows that Appliance makers are usually 100 percent correct that there is nothing wrong with the appliance, and is the supply items and the OEM's that are causing the problems. THAT is why it appears that Dometic seems to "flake" off. They KNOW there is nothing wrong with the Refer and cannot force incompetent Service people to step up. Doug

[ernie1]

dougrainer: Neither of my friends nor I have slides in our rvs and since we have identical problems common to two different models of new Dometic fridge in that the fridges work fine on ac but poorly on propane I'm certain that the issue is propane related and less an improper installation. Question is, what to look for that the rv repair shops in conjunction with Dometic techs can't resolve. I think Dometic has flaked on this issue. My thinking is either an undersized gas jet, a crimp or restriction somewhere in the gas supply system (which might be a Dometic design issue). Gonna check the gas supply pressure and, if less than 11.5, adjust the regulator accordingly. Can't get any info on the proper jet size nor availability because Dometic says they can't give that info out nor can they give any references probably due to a liability issue. So Doug, what do you think?

[dougrainer]

JRscooby wrote:

dougrainer wrote:

Also, Are any of you or your friends refer installed in a slide room? THAT is also a different situation that usually calls for a separate exhaust fan blowing out the top door. Doug

I can not disagree with this, but just for my understanding, could you tell me why this is true?

Simple. The normal install for a RV refer is to have the cold air come in thru the bottom outside door and convection the air thru the condenser and up and out the roof vent. Normal convection air gets this done. Larger RV refers need an addition fan to help blow the air up and out, which the refer maker installs if needed. Now, when you have the refer in a slide out, the air flow IS going up, but must make a 90 degree turn and out the upper vent door since you do not have a roof vent in a slide room. Most OEM's do a poor job of making the upper wood cabinet with the required wood baffles to help turn that air and out the upper door. So, a lot of the hot air stays caught behind the upper refer and allows poor ventilation and cooling. Sooo, what I do is modify the upper back of the cabinet to seal off any place that can trap air. I then add just 1 12 volt refer fan just inside that upper door blowing out to force the hot air out the upper door. Also, when you remove that upper door and you can see most ofthe condenser fins, that is also a problem. That is why it is critical to make sure you have a wood baffle as close to the back side of those fins to make sure the cooling air goes thru the condenser instead bypassing between the sidewall and the condenser. THIS is the most common OEM error on baffling the refer cabinet. Doug

[JRscooby]

dougrainer wrote:

Also, Are any of you or your friends refer installed in a slide room? THAT is also a different situation that usually calls for a separate exhaust fan blowing out the top door. Doug

I can not disagree with this, but just for my understanding, could you tell me why this is true?

[dougrainer]

ernie1 wrote:
Ok Doug my refrigerator is a Dometic RML 8555 absorption unit and it's less than a year old. My one friend has an identical unit about the same vintage and the same brand of motorhome and the same problem. Another friend has the same brand of rv and it's also essentially new but the fridge is a smaller model Dometic and I don't know the model number but he has the exact same problem. These friends of mine have had their gas regulator,gas solenoid valve and board changed, burner cleaned etc under the watchful eye of Dometic who covered some or most of it under warranty. Bottom line, Dometic says that's the way the fridges perform and don't expect much more than something like 43 deg in the fridge at about 85 ambient. In addition, these fridges have underperformed like this when they were brand new and it's taken months of harping to Dometic to get nowhere. I haven't checked the gas pressure yet but will do that next. Since I have a newish Marshall gas regulator, should I adjust it to increase the pressure if necessary? To be clear, the freezer works fine on ac and propane but the refridge works fine on ac and barely on propane.

A LOT of my B+ motorhomes have the 8555. NEVER have had a complaint of poor lower section cooling that could NOT be fixed. Very rare to even have that complaint on the 8555. INSTALLATION parameters are HUGE in the correct operation of any RV refer. The rear cooling air must be routed up and out correctly and it is a must that the cooling air is routed THRU the fins of the condenser. Any gap between the edge of those fins and the outer wall will allow cooling air to flow away and not thru the fins. Also, Are any of you or your friends refer installed in a slide room? THAT is also a different situation that usually calls for a separate exhaust fan blowing out the top door. Doug

[ernie1]

NRALIFR Thanks for the info. I see now that I can probably hook up to a test port in my unit. But I want to take this a little further and try to test the solenoid gas valve so I'll need a different sized fitting. I think I can get a complete set from the online seller for my YELLOW JACKET.

[ernie1]

Ok Doug my refrigerator is a Dometic RML 8555 absorption unit and it's less than a year old. My one friend has an identical unit about the same vintage and the same brand of motorhome and the same problem. Another friend has the same brand of rv and it's also essentially new but the fridge is a smaller model Dometic and I don't know the model number but he has the exact same problem. These friends of mine have had their gas regulator,gas solenoid valve and board changed, burner cleaned etc under the watchful eye of Dometic who covered some or most of it under warranty. Bottom line, Dometic says that's the way the fridges perform and don't expect much more than something like 43 deg in the fridge at about 85 ambient. In addition, these fridges have underperformed like this when they were brand new and it's taken months of harping to Dometic to get nowhere. I haven't checked the gas pressure yet but will do that next. Since I have a newish Marshall gas regulator, should I adjust it to increase the pressure if necessary? To be clear, the freezer works fine on ac and propane but the refridge works fine on ac and barely on propane.

[dougrainer]

ernie1 wrote:
Hey guys, I'm confused. dougrainer and NRALIFER in particular: I presently have a YELLOW JACKET gas pressure test kit model 78060 that I just purchased and haven't used yet and was wondering if the digital units that was mentioned would be a better unit to have than my YELLOW JACKET? The YELLOW JACKET requires different fittings for testing. Does the digital units not? How do they work for reading gas pressures? By the way, I and my two friends with relatively new Dometic refrigerators are having the same problem though not as extreme as the op and the company essentially says that that's the way they are and that these units are "coolers" and not really refrigerators. It sucks big time when you pay $150,000+ for your rv and only get a "cooler".

State your Brand and Model number. I have NEVER--NEVER had either Norcold or Dometic state such nonsense that they are essentially coolers. What YOU wanted was free help and Both Norcold and Dometic do not give free help or diagniosis. As another poster stated, the OEM if not installed to spec some refers will not work. Installed to spec they will work. Doug

[dougrainer]

I have been working on Refers/Dash AC's and Roof Ac's for 40 years and still working. I can state that the slower the air thru an evap fin will yield colder air. Maybe Canada does not follow laws of Physics:B Those that state faster air flow has NO affect, explain WHY on both Dash Ac's and especially roof Ac's the units can freeze up while on LO SPEED and the fix is to run on HIGH SPEED to prevent freeze ups when there is no tstat used to prevent freezing??????? I stand by my 40 years of experience on what I have stated. Doug

[dougrainer]

JRscooby wrote:

ernie1 wrote:
Hey guys, I'm confused. dougrainer and NRALIFER in particular: I presently have a YELLOW JACKET gas pressure test kit model 78060 that I just purchased and haven't used yet and was wondering if the digital units that was mentioned would be a better unit to have than my YELLOW JACKET? The YELLOW JACKET requires different fittings for testing. Does the digital units not? How do they work for reading gas pressures? By the way, I and my two friends with relatively new Dometic refrigerators are having the same problem though not as extreme as the op and the company essentially says that that's the way they are and that these units are "coolers" and not really refrigerators. It sucks big time when you pay $150,000+ for your rv and only get a "cooler".

To test gas pressure you will need to get inside the line, get the pressure to the gauge.
As for the "cooler" idea. The absorption type fridge has been around much longer than a compressor style, and when properly installed can work real good as refrigerators. For a home unit, built and shipped in a self contained cabinet they could be great, except with the same sealing and insulation, they use more power, and in a tight sealed room burning the oxygen might be a issue. The problem in RVs is the RV builder must build the cabinet. And the sloppy workmanship results in bad insulation and worse air flow in many cases. And they got your money, why should they care how well the fridge works?
If you go back to a earlier post this thread you can read a description of what some call a MOD, but I call proper installation to make it cool better.
BTW, Doug and others that work on RVs often should spend the money to buy the tools to check the pressure. I, in the last 20 years, have needed to check propane pressure twice and NG once. My tube and yardstick has worked every time.

We have a liquid tube manometer on the wall we check and adjust our Manomters with. I don't use the digital manometers. Don't see the need. Doug

Similar to this. We are required to calibrate them numerous times a year. It is required by The Texas Railroad Commission and we also have to licensed to service LP and NG in Texas by the TRC

https://www.energyconscious.com/dwyer-mini-u-tube-manometer-mu-14.html?fee=5&fep=13826&gclid=EAIaIQo...

[JRscooby]

ernie1 wrote:
Hey guys, I'm confused. dougrainer and NRALIFER in particular: I presently have a YELLOW JACKET gas pressure test kit model 78060 that I just purchased and haven't used yet and was wondering if the digital units that was mentioned would be a better unit to have than my YELLOW JACKET? The YELLOW JACKET requires different fittings for testing. Does the digital units not? How do they work for reading gas pressures? By the way, I and my two friends with relatively new Dometic refrigerators are having the same problem though not as extreme as the op and the company essentially says that that's the way they are and that these units are "coolers" and not really refrigerators. It sucks big time when you pay $150,000+ for your rv and only get a "cooler".

To test gas pressure you will need to get inside the line, get the pressure to the gauge.
As for the "cooler" idea. The absorption type fridge has been around much longer than a compressor style, and when properly installed can work real good as refrigerators. For a home unit, built and shipped in a self contained cabinet they could be great, except with the same sealing and insulation, they use more power, and in a tight sealed room burning the oxygen might be a issue. The problem in RVs is the RV builder must build the cabinet. And the sloppy workmanship results in bad insulation and worse air flow in many cases. And they got your money, why should they care how well the fridge works?
If you go back to a earlier post this thread you can read a description of what some call a MOD, but I call proper installation to make it cool better.
BTW, Doug and others that work on RVs often should spend the money to buy the tools to check the pressure. I, in the last 20 years, have needed to check propane pressure twice and NG once. My tube and yardstick has worked every time.

[JRscooby]

ernie1 wrote:
Hey guys, I'm confused. dougrainer and NRALIFER in particular: I presently have a YELLOW JACKET gas pressure test kit model 78060 that I just purchased and haven't used yet and was wondering if the digital units that was mentioned would be a better unit to have than my YELLOW JACKET? The YELLOW JACKET requires different fittings for testing. Does the digital units not? How do they work for reading gas pressures? By the way, I and my two friends with relatively new Dometic refrigerators are having the same problem though not as extreme as the op and the company essentially says that that's the way they are and that these units are "coolers" and not really refrigerators. It sucks big time when you pay $150,000+ for your rv and only get a "cooler".

To test gas pressure you will need to get inside the line, get the pressure to the gauge.
As for the "cooler" idea. The absorption type fridge has been around much longer than a compressor style, and when properly installed can work real good as refrigerators. For a home unit, built and shipped in a self contained cabinet they could be great, except with the same sealing and insulation, they use more power, and in a tight sealed room burning the oxygen might be a issue. The problem in RVs is the RV builder must build the cabinet. And the sloppy workmanship results in bad insulation and worse air flow in many cases. And they got your money, why should they care how well the fridge works?
If you go back to a earlier post this thread you can read a description of what some call a MOD, but I call proper installation to make it cool better.
BTW, Doug and others that work on RVs often should spend the money to buy the tools to check the pressure. I, in the last 20 years, have needed to check propane pressure twice and NG once. My tube and yardstick has worked every time.

[NRALIFR]

Nothing wrong with your Yellow Jacket test kit, or a digital unit like the one I linked to. Both require the same type of connection to the LP system, one just displays the pressure in an analog/mechanical fashion, the other displays it digitally/electronically.

Both types of gauges would need to be calibrated periodically, or at least checked against a real water column manometer to ensure its accuracy. That’s probably why a lot of guys prefer to simply make one out of clear tubing and a ruler. Unless your ruler shrinks or grows, or you use one of those fisherman’s rulers that always measure long, there’s no calibration needed.

The Yellow Jacket kits I’ve seen have always come with a tube nipple to connect the gauge to a test port. Is yours not the right size? Have you located a test port?

Here’s a picture of the backside of my fridge, showing the location of the best test port you should use when checking the LP pressure to the fridge burner. Unfortunately, that plug on mine is stuck and I couldn’t get it out. There are a couple of other test ports on my camper. My regulator at the LP tanks has a test port, so I used that one instead.



There are a lot of little things that can cause an absorption fridge to not perform well, and low LP pressure is one of them. If your fridge works well on AC, and poorly on LP, you have an LP problem, not a cooling unit problem.

The statement that they are coolers is totally false. If they are working right, you should see it maintain around 0-10 degrees in the freezer, and 35 degrees in the fridge section. In fact, these are the temps I typically see on my fridge. The fridge probe is right under the cooling fins. This was when I was in Phoenix last year, and the outside temp was over 100, and inside the camper was about 78.



:):)

[ernie1]

Hey guys, I'm confused. dougrainer and NRALIFER in particular: I presently have a YELLOW JACKET gas pressure test kit model 78060 that I just purchased and haven't used yet and was wondering if the digital units that was mentioned would be a better unit to have than my YELLOW JACKET? The YELLOW JACKET requires different fittings for testing. Does the digital units not? How do they work for reading gas pressures? By the way, I and my two friends with relatively new Dometic refrigerators are having the same problem though not as extreme as the op and the company essentially says that that's the way they are and that these units are "coolers" and not really refrigerators. It sucks big time when you pay $150,000+ for your rv and only get a "cooler".