Q Why is my fridge not working on mains?

We have a Thetford fridge/freezer (model N3170) in a 2016 Carado T448 on a Fiat Ducato. It was working on electric hook-up for six days when the light started flashing with a ‘number 8’ spanner code. It works perfectly fine on gas and 12V when the engine is running.

We tried switching it off for a period of time but it still didn’t connect to mains. We have removed the bottom outside fridge vent and checked for 230V on both sides of the mains connector up to the fridge with a multimeter; the reading was 239V. All other systems in the motorhome work fine. Any advice would be really appreciated.

Lesley White

ABefore you do anything, make sure the mains hook-up lead is disconnected from the motorhome.

That fault code indicates that the mains heater element is taking less than 25% of the amps it should. As your mains voltage is well within specification, did you check the 2A mains fuse in the back of the fridge?

A qualified electrician would use a multimeter set to AC amps to measure the mains current going into the fridge. This should be just over one amp. Or there is a bad connection to the element.

I believe you most likely need a replacement mains heating element for the fridge, which has probably gone open circuit. This is the second thing to check with a multimeter. The resistance of this element should be about 210 ohms.

The last and more expensive repair is if the control PCB is telling lies and needs replacing. You will require the unit serial number to determine the correct part, but Thetford should be able to pinpoint the right code using a fault-finding diagram, and more information on the fridge can be found at thetford-europe.com/gb/ products/refrigerators/absorption/ n3170a

Take care and always use a professional if in any doubt.

Clive Mott