A class fault finding

Hi all

I've just moved into a new(ish) build flat and have an A-Class supplying HW.

Only problem is the off peak heater doesn't work at all. I contacted the owner and the previous tenants, they both said it never worked for them and just boosted when they needed to top it up........madness. Then the owner said he didn't get any large bills so we shouldn't worry. Clearly that was before the electricity price hikes. Anyway....

Off peak is supplied by a separate timer switch which is working fine. I have done some fault finding too.

Immersion element has good resistance. All fuses are working, relays are working and contactors are fine but the digital display shows that it is not receiving an off peak supply.

I get a couple of lock out codes (29) on C1 and C2 but i dont know what they mean.

The only thing i can think it must be is the PCB, and maybe specifically the relays on the board.

Any tips on how to find the actual fault? where to get the board from/cost?? and maybe what components are prone to failure on the board and how to replace them?

Thanks

Hi,
Look on here and you will find a link to down load the manual.
Also on the home page where to buy parts.
Mike

I think you will find fault code 29 is relay.
But you have
On peak relay
Off peak relay
Interface relay.
And relays on the main board (ACB)
Mike