Howdy,

I sadly have one of those DIY inverter B&Q split units that decided that has decided to not play nice anymore and trip the MCB in cool or heat mode.

B&Q deny ever selling these and finding any info is proving near impossible.

It was used in heat mode last year - then pop the MCB tripped and I left it alone. Now the temps have risen I thought I would take a look at it.

The indoor unit works fine. Compressor and fan all check out along with start caps etc. I have gone over the main PCB and can't see anything obvious like swollen caps, or burn't out components.

If I disconnect the compressor & fan, I get the exact same symptoms as if they were plugged in.

This is what it is doing:

Internal unit fan on, gets upto speed. Select cool mode. Wait the 3 mins for the compressor to start.

On the outdoor PCB, the red power led comes on. Then it does 8 red led flashes and 6 yellow led flashes. After a 2 second wait it briefly starts the error code flash again and trips the MCB.

I have isolated it onto it's own 32Amp MCB just incase there was anything else on the circuit that was interfering. The MCB it was on happily for 2 years is a type B curve.

I am now stumped to know what it up with it. I am sure I have taken the fan, cap and compressor out of the loop so it can't be these.

Yeah I know that I should rip it out and get something decent, but before I do I really want to see if it is a simple fix.

I guess some of you attend these B&Q units and may have seen similar problems. Maybe all the gas is out, but until i get an engineer out to check it - this looks electrical.

The last thing I can try is to replace the MCB with a type C, because I think it is a bit trippy as our old oven would trip it too.

Any pointers or ideas to debug this would be greatly appreciated before I write it off.

Cheers!