Sub-Zero drawer fridge tripping the breaker: failed defrost heaters
When a Sub-Zero refrigerator keeps tripping the breaker or the RCD, the fault can be in the defrost heaters rather than in the compressor or the control board. That is what LE Company engineers found this October in a home in Westminster, on a new Sub-Zero integrated two-drawer refrigerator / freezer with an ice maker (model ICBID-30CI). Here is how we traced the fault and what fixed it.
Why is my Sub-Zero refrigerator tripping the breaker?
The customer told us the new Sub-Zero kept tripping the electrical circuit, and it had been switched off by the time we arrived. We removed the front grille and inspected the machine compartment. If your Sub-Zero is not tripping but has stopped cooling, see why a Sub-Zero fridge stops cooling properly.
How do you find out what is tripping the RCD on a fridge freezer?
We ran the appliance one function at a time. Everything worked normally, and the ice maker passed a full test (for ice maker faults, see our Sub-Zero ice maker repair page). Then we ran the defrost test, and the RCD tripped as soon as the defrost heaters were energised. There are three heating elements in that circuit on this model.
To rule out the electronics, we removed the main control board and inspected it. It was intact, with no visible damage, so we refitted it. Our conclusion was a fault in the defrost heating elements, and we recommended replacing all three.
What should I do if my fridge freezer keeps tripping the RCD?
Switch the appliance off and leave it off until an engineer has found the fault. An RCD trips because current is leaking to earth, so resetting it again and again is not a fix. Our engineers left this Sub-Zero switched off until the new parts were fitted.
The repair: three new Sub-Zero defrost heating elements
On the return visit we replaced the three defrost heating elements with original Sub-Zero parts (part numbers 7025952, 7040522 and 7011756), reassembled the unit, switched it on and tested it. It passed. The earth fault had been in the defrost heaters, as diagnosed on the first visit, and no further work was needed.
Sub-Zero defrost heater faults are worth repairing
A failed defrost heater can make an expensive, almost new Sub-Zero look dead, but it is a repairable fault. Finding it took a methodical test of each function, and fixing it took three original parts. For what Sub-Zero repairs usually cost, and when an older Sub-Zero is worth repairing, see our Sub-Zero repair cost guide.
Book a Sub-Zero repair in London
LE Company’s call-out is from £175 + VAT and includes the first 30 minutes on site, when the engineer finds the cause of the fault. The cost of the repair is agreed with you before any work starts, and we fit only original Sub-Zero parts. See our Sub-Zero repair in London and Sub-Zero freezer repair pages, read the signs your fridge needs repair, or call +44 20 3603 7172, Monday to Saturday, 8am to 8pm. Prices, parts warranty and insurance are covered in our frequently asked questions.