BLUF - How do I keep fridge cooling unit from forming crystals? We spend most of the year work camping. We spend five months in one location, then take a month of traveling to the next location. Our Norcold 1200 fridge has been having cooling problems. We had a technician look at it and was told the cooling unit was blocked with crystals and would eventually need to be replaced. The tech even went so far as to suggest banging on the canister to loosen the crystals. We have started our move to the next locale and it seems the crystals have broken loose again. The fridge now works great. So good, I had to turn it down because it’s getting too cold. So, once we get to our work location, how do I keep it from getting blocked again? Should I bang on the canister once a week, or just when it stops cooling again? Eventually, when funds become available, it will be replaced. But until then...

My understanding as this can be caused by running out-of-level. But, I am not sure if this is true.Steve

A properly-running refer doesn't need to be banged on. You may get by doing that for a while, but I'd start saving my money.And yes, the above is true.

Two answers1: you don't2: Fans. I have a pair of 12 volt "Comptuer" fans hooked to the light circuit (Before the switch so they are on all the time) one is a higher capacity and that end of the cooling fins is very clear of ice. the other end has some ice but the fan is not as "Fast".. They make a set of fans designed to attach to the TOP of the Fridge. along with an LED light in the assembly.. I don't have a link handy but plan on converting one day.

I think your saying the crystals are inside the cooling system not the evaporator ?

Sodium Chromate (rust inhibitor in the coolant solution) forms crystals when overheating occurs (overheating of the coolant due to lack of proper gravity flow due to off level operations)Crystals plate out on interior of cooling unit tubes......can be in perk tube (boiler section) and/or in tubing between freezer cooling coil and food compartment cooling coil.Formation is accumulative and PERMANENT. (once formed they do NOT go back into solution) Banging may dislodge some from the tubing which can allow for increase in coolant flow but the dislodged crystals just flow into another area of tubing.Once formed it is just a matter of time before cooling unit can no longer function OR cause enough restriction of coolant flow that the tubing is heat stressed (coolant no longer absorbing heat) and the tube cracks....ammonia/hydrogen gas spew out (300 psi)Plan ahead!

Fridge cooling unit forming crystals-help! | Good Sam Community

maillemaker
Explorer
Apr 09, 2019
My understanding as this can be caused by running out-of-level. But, I am not sure if this is true.

Steve
2oldman
Explorer II
Apr 09, 2019
A properly-running refer doesn't need to be banged on. You may get by doing that for a while, but I'd start saving my money.

And yes, the above is true.
wa8yxm
Explorer III
Apr 09, 2019
Two answers
1: you don't
2: Fans. I have a pair of 12 volt "Comptuer" fans hooked to the light circuit (Before the switch so they are on all the time) one is a higher capacity and that end of the cooling fins is very clear of ice. the other end has some ice but the fan is not as "Fast".. They make a set of fans designed to attach to the TOP of the Fridge. along with an LED light in the assembly.. I don't have a link handy but plan on converting one day.
fairway2002
Explorer
Apr 10, 2019
I think your saying the crystals are inside the cooling system not the evaporator ?
Old-Biscuit
Explorer III
Apr 10, 2019
Sodium Chromate (rust inhibitor in the coolant solution) forms crystals when overheating occurs (overheating of the coolant due to lack of proper gravity flow due to off level operations)

Crystals plate out on interior of cooling unit tubes......can be in perk tube (boiler section) and/or in tubing between freezer cooling coil and food compartment cooling coil.
Formation is accumulative and PERMANENT. (once formed they do NOT go back into solution) Banging may dislodge some from the tubing which can allow for increase in coolant flow but the dislodged crystals just flow into another area of tubing.

Once formed it is just a matter of time before cooling unit can no longer function OR cause enough restriction of coolant flow that the tubing is heat stressed (coolant no longer absorbing heat) and the tube cracks....ammonia/hydrogen gas spew out (300 psi)

Plan ahead!
dougrainer
Nomad
Apr 10, 2019
You did NOT have a "tech" look at your refer. You had a Handy man idiot look at your refer. REAL RV Techs do not give such bad advice. Doug
Airdaile
Explorer
Apr 10, 2019
Sitting for that length of time, I would get a residential fridge and an inverter to run it for the one month a year on the road.
kaydeejay
Explorer
Apr 10, 2019
Bottom line - your fridge is done!! A new one (or at least a cooling unit replacement) are in your not very distant future!!
An inverter and residential fridge may make more sense if you have the battery capacity to run it.
wa8yxm
Explorer III
Apr 10, 2019
I covered ICE crystals on the fins.. "Crystals" inside the tubes .. How can you see them???
Boon_Docker
Explorer III
Apr 10, 2019
^ X-Ray vision I believe.

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Fridge cooling unit forming crystals-help!

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