ARP Refrigerator Protection
I've seen advertisements in the Escapees magazine for the ARP refrigerator protector which claims to protect Dometic/Norcold refrigerator boilers from overheating. Have any of you installed this pr...
Forum Discussion
There are 2 main reasons* an absorption unit can fail- it can leak, or it can become blocked.
There are 2 reasons it can become blocked, manufacturing defect- a bit of welding slag left in the unit, and the sodium tetrachromate being overheated and solidifying, blocking the boiler. The first problem will normally manifest itself in the warranty period, the second is always due to off level operation**
Leaking is usually due to internal corrosion of the evaporator, internal corrosion of the boiler, or stress fractures at the boiler. The boiler failures are usually due to overheating, often caused by off level operation.***
I have rebuilt literally hundreds of these refrigerators, probably half due to blocked units.
*There is another failure mode which is very hard to diagnose, and that is caused by overheating producing another gas, which displaces the hydrogen. The chemical theory behind that is above my pay grade.
**This failure mode is usually gradual, a slow decrease in performance.
***One thing about off level operation- the ARP really doesn't care how level the unit is, and bottom line is level is just a metric we can measure easily. What matters is the boiler temperature, which needs to be high enough to vaporize the ammonia, but below the boiling point of water. If the refrigerant is circulating, it doesn't matter about level.
There are 2 reasons it can become blocked, manufacturing defect- a bit of welding slag left in the unit, and the sodium tetrachromate being overheated and solidifying, blocking the boiler. The first problem will normally manifest itself in the warranty period, the second is always due to off level operation**
Leaking is usually due to internal corrosion of the evaporator, internal corrosion of the boiler, or stress fractures at the boiler. The boiler failures are usually due to overheating, often caused by off level operation.***
I have rebuilt literally hundreds of these refrigerators, probably half due to blocked units.
*There is another failure mode which is very hard to diagnose, and that is caused by overheating producing another gas, which displaces the hydrogen. The chemical theory behind that is above my pay grade.
**This failure mode is usually gradual, a slow decrease in performance.
***One thing about off level operation- the ARP really doesn't care how level the unit is, and bottom line is level is just a metric we can measure easily. What matters is the boiler temperature, which needs to be high enough to vaporize the ammonia, but below the boiling point of water. If the refrigerant is circulating, it doesn't matter about level.
