Norcold N300.3 Refrigerator: Not Cooling On LP

[FlyboyTR56]

Hello...

First post and happy to be here. Lifelong camper with everything from our 40' Allegro Bus to hammocks. We still enjoy all aspects of camping. I have always done my own maintenance and repair so I am well versed in most of the RV systems. However, today I have hit a brick wall and need some advise.

Our travel trailer (2007 Trailmanor 2720), has a Norcold N300.3 refrigerator. Back in the spring the performance on LP started declining. This camper gets used a lot (25k+ miles in the past two years). I found that the burner was badly rusted and installed a new one. That put the snap back into things. It performed great. About two months ago the LP performance starting declining to the point of not being able to use the LP for cooling.

In the past week I have removed the burner (perfect), removed the flu (chimney) baffle and cleaned everything. There was quite a bit of ash buildup in the flu. Everything is clean. Put it all back together and it is still not cooling properly. The flame is blue with no noted issues. The freezer gets to about 35 but the refer is still around 65-68 degrees after 24 hours. I can switch to electric (110vac) and everything cools properly.

So, I am at a loss as to what may be going on with the LP side of things. We're leaving in 8 days for a 4 weeks trip and not having the refer working on LP will be a problem since we are boondocking about half the time. Any suggestions would be greatly appreciated. Thanks!

FlyboyTR56

[Old-Biscuit]

Stove has it's own LP Reg (Under stove top) --- set to hold 10"WC (0.36 psi)
LP Main Reg set to hold 11"WC *0.39 psi)

You can NOT tell the difference between correct LP Pressure and Low LP Pressure visually

Flow Limit Check Valve inside the GREEN ACME Nut. If tripped it limits propane flow if a leak occurs downstream OR if Service Valve/OPD is opened too quickly
To reset ---close Service valve then SLOWLY open it....no need to disconnect pigtail

[FlyboyTR56]

ktmrfs wrote:

FlyboyTR56 wrote:

ktmrfs wrote:
remove the propane orifice (jet) and make sure it is clean. It is so small that even a bit of dust or spider web will reduce flow and result in poor cooling. It may still have a blue flame, but just not big enough.

Thanks. I blew carb cleaner through it and then compressed air, both directions. The flame appears to be the same size as it had been when working properly. However, I am willing to pull it back out and clean it again.

look at the orifice with a magnifying glass. make sure the hole is clean.

But it looks like you have gone through the obvious things. One more thing to verify. Are you POSITIVE the OPD valve on the propane tank isn't tripped? Turn on a burner on the stove, make sure you have a full flame. If not, the tank opd valve may have been tripped when you turned on the propane. turn off the valve, take off the pigtail, reinstall and SLOWLY turn gas back on.

Good suggestions! This morning I thought about LP pressure. Turned on the three burners on the stove, then fired up the water heater...no change in flame on the stove. I then turned the thermostat up on the furnace and let it fire. Still no change in visible flames except for the instant the furnace valves opens.

I may have to pull the burner one more time and recheck the orifice. It is just SO hard to get to. Thanks again!

[ktmrfs]

FlyboyTR56 wrote:

ktmrfs wrote:
remove the propane orifice (jet) and make sure it is clean. It is so small that even a bit of dust or spider web will reduce flow and result in poor cooling. It may still have a blue flame, but just not big enough.

Thanks. I blew carb cleaner through it and then compressed air, both directions. The flame appears to be the same size as it had been when working properly. However, I am willing to pull it back out and clean it again.

look at the orifice with a magnifying glass. make sure the hole is clean.

But it looks like you have gone through the obvious things. One more thing to verify. Are you POSITIVE the OPD valve on the propane tank isn't tripped? Turn on a burner on the stove, make sure you have a full flame. If not, the tank opd valve may have been tripped when you turned on the propane. turn off the valve, take off the pigtail, reinstall and SLOWLY turn gas back on.

[FlyboyTR56]

ktmrfs wrote:
remove the propane orifice (jet) and make sure it is clean. It is so small that even a bit of dust or spider web will reduce flow and result in poor cooling. It may still have a blue flame, but just not big enough.

Thanks. I blew carb cleaner through it and then compressed air, both directions. The flame appears to be the same size as it had been when working properly. However, I am willing to pull it back out and clean it again.

[Old-Biscuit]

Still using the original LP Regulator from 2007

Time for a new one.
LP System Pressure is low so although flame looks good it is NOT as hot therefore NOT enough ammonia is being turned into hot vapor from boiler section
So freezer section is using up all of the absorption capacity and not getting cold enough

Cooling unit is functioning on 120VAC OK so it is NOT the cooling unit

Cleaning of orifice is always a good idea.
Remove and soak in alcohol then air dry *No poking anything thru it OR using high pressure air. Damage the metered hole and you will need new orifice

[ktmrfs]

remove the propane orifice (jet) and make sure it is clean. It is so small that even a bit of dust or spider web will reduce flow and result in poor cooling. It may still have a blue flame, but just not big enough.