Recently I could not keep my Dometic RM7832 running, as my Fridge Defend was shutting it down and going into boiler overheat protection mode. Checking the boiler temp at the Fridge Defend display though showed the boiler temp to be 370F, which is well within normal operating range (365 - 383F.) So the problem may not be your fridge; but rather the Fridge Defend installation.
The Fridge Defend instructions me showed how to view diagnostic variables, some of which were:
AbS: 570F (Maximum boiler temp seen),
tr: 028 (# of times triggered), and
OPn: 090 (# times problem with boiler sensor wiring).
This last one clued me into opening up the boiler housing to access the sensor wires and sure enough, I found the sensor wires frayed from rubbing on the boiler housing. Apparently what happened was the metal tape installed around the boiler housing failed and sprung the sheet metal, and that brought the sensor wires into contact with a sharp edge on the housing.
I taped up the wires with electrical tape and padded them with insulation to better protect from chafing, then put everything back together, though this time I added a stainless steel hose clamp around the boiler housing to keep it from springing open.
Finally I reset all of the Fridge Defend diagnostic variables and started the fridge up again. It’s been running perfectly for the last 24 hours, both on AC and in gas mode.
BTW after discovering the frayed sensor wires I filled out the contact form
here on the Fridge Defend website to ask for advice, and I got a response back from Paul within 30 minutes. It was his suggestion that I try taping and re-securing the wires, and it worked.
Finally, for reference here are my cheat notes on how to use the Fridge Defend diagnostics:
Temp & voltage readings when ARP is on:
Hold Display button for 2 seconds to scroll through to see:
- Boiler temp (operating range 365 - 383F)
- Fan sensor temp
- Voltage
Check variables in Setup mode:
- Shut off ARP (Hold On/Off button until done displaying OFF)
- Enter Setup mode: Hold Setup, press On/Off, release Setup when AtO appears
- Scroll through with Display button - first the variables (about 20), then the Store function (S–), finally Error history (Er0).