Norcold fridge doesnt cool on LP

[nvs4602]

Did they test the gas pressure at the refrigerator after the gas valve? It should be 11" w.c. there. Take a dental mirror and stick it under the burner and look up the fire tube. The defuser (the spiral thingy) should be about 2" up from the bottom of the fire tube and glowing red hot. It that all looks ok I would order a new orfice for it.

[Old-Biscuit]

Originally Posted by graphite9

Once again thank you guys! The spiral desk inside the flue is in place and the rod that suspends the spiral is bent at the top to clip it into the top of the flue. And the cap is on. I’m totally lost. But yes I do agree for some reason the flame isn’t creating enough heat unsure the flu for some reason. I felt like it worked at first when we had it and it gradually got worse.

But it’s hard to say cause most our road trips were short and we were on shore power most the time

LP System pressure......11"WC (0.4 psi) is what should be


10"WC (0.36psi) is not visually noticeable and furnace/water heater/stove top burners can all function
Fridge with its small btu orifice/burner it can make a BIG difference in flame temp/heat transfer.


Measure the LP System Pressure with at least 50% of appliances in service


Simple manometer hooked up to test port on fridge gas valve...water heater on & all stove top burners on HIGH


2' piece of wood attached to flat piece so it stands up right
some clear tubing...barbed fittings plus 1/8" screw in fitting for fridge gas valve test port


Mark off Zero Line then 1/2" marks Above/below zero
Fill tubing so both sides are level at zero
Light off fridge burner with the other stuff in service
Level moves up/down 5 1/2" each direction---11"WC


Less ...then need to adjust LP Reg (cap/plug on mainbody with adjustment screw underneath. Turn screw IN increases spring tension/higher pressure to system
(Or replace reg with new one)

[Gary RVRoamer]

Not only is the flame normal (pix in post #6), you can see the glowing red heat baffle. Somehow that heat is not getting transferred adequately. Given the reports so far, I'm at a loss to guess why.


Thanks to Old Biscuit for that most excellent and succinct description of how the gas flame heats the boiler. I've read several tech papers on absorption fridges that used 100's of words and conveyed far less helpful information!

[graphite9]

hey guys, i checked and made a manometer, as per the instructions above (thanks

Im at 11" right on the money, with all appliances running. so now, I'm at a loss even more. new burner, blue flame, clean flue, new regulator, new thermistor and still not cooling on LP.

[Old-Biscuit]

Originally Posted by graphite9

hey guys, i checked and made a manometer, as per the instructions above (thanks

Im at 11" right on the money, with all appliances running. so now, I'm at a loss even more. new burner, blue flame, clean flue, new regulator, new thermistor and still not cooling on LP.

Unplug that new thermistor.....
Run on LP for 12 hrs minimum w/o thermistor and then check freezer & food compartment temps

[shootist]

It must be shutting down , cycling. Maybe you got terribly unlucky and it has gone into it's 49 hour between defrost on you on propane. Shutting it off at the control panel and turning it back on will reset the clock, switching from ac to propane won't. The heat sensor at the top in back may also shut it down. AC they don't get quite as hot as propane.

[avfordguy]

The issue is, .....no heat transfer on propane, with a good flame...remove spiral baffle and get a couple of copper pipe cleaners that look like round wire brushes and clean the flue from the top, reason it does good on 110v is those heaters are in direct contact with the boiler. BTDT.

[graphite9]

Originally Posted by avfordguy

The issue is, .....no heat transfer on propane, with a good flame...remove spiral baffle and get a couple of copper pipe cleaners that look like round wire brushes and clean the flue from the top, reason it does good on 110v is those heaters are in direct contact with the boiler. BTDT.

Thanks for the tip. However I’ve already done that. Spiral is in great shape cap is on and flue is sparking clean

[graphite9]

I’ve yet to see the flame shut off. It’s always on. This one definitely has me stumped. How does the fridge manage a certain temp on Lp? As it can’t control the flame level. Does it cycle as you said?

[hoakken]

It may have been suggested but I replaced my propane regulator and not only got my furnace working with the added result of the fridge cooling faster and colder. Cheap thing to try.

Never mind I just saw the regulator was replaced.

[Old-Biscuit]

Originally Posted by graphite9

I’ve yet to see the flame shut off. It’s always on. This one definitely has me stumped. How does the fridge manage a certain temp on Lp? As it can’t control the flame level. Does it cycle as you said?

Fridge has ONE thermostat that controls heating cycles based on temp feed back from thermistor....electric or propane (thermostat turns electric element on/off and shuts down/relights LP flame as needed)



Fridge cools properly on AC then it should also cool properly on LP unless LP Components are faulty.


But..........clean flue, new flue baffle, burner/orifice, LP System at 11"WC and LP Flame strong, Blue then fridge temps should cool down.


Run it on LP w/o thermistor connected (unplug it)

[153stars]

Didn't read every post. Is it new to you unit.Has it ever cooled well on LP
Was there a wire with spiral hanging down from the top of flue. People have found them missing on new to them RVs
Went back someone mentioned removing it to clean the flue. You said it's there. There are different lengths of wire hanging them per model. I guess its a very remote possibly the spiral is not where it should be.

[Ray,IN]

Old-biscuit has covered virtually everything that can be said. I might add, another possibility is the refrigerator gas valve not opening fully.However the manometer should have revealed that issue, if the gas pressure was measured downstream of the fridge gas valve.

[Old-Biscuit]

Run it on LP w/o thermistor.....
IF it does cool down ---thermistor is suspect (even a new one)


But I bet you will find it is in fact the circuit board ----LP circuit is faulty.