Hello again, I have contacted the electrician to come and have the look at those heaters, finally he might come and before the visit the sent me the message - part of the message is below:Sorry I haven't replied for a while.
Thank you for the pics, which indicate there is nothing untoward with the power arrangements.
I'm afraid, basically, I know nothing about the controller!
If you decided to try it, I would recommend setting the clock to the correct time.
But I'm inclined to believe the background heating should work with the controller switched off - something you might check with neighbours if you haven't already. If that is the case, I would leave the controller 'off'.
So it seems there's no explanation for heaters not working, other than some failure(s) inside.
As far a water heating is concerned, it seems the main heater is directly on the night rate supply, and although there is the RXPWIF switch there, it's not actively timing the water heater. That's not a problem.
So I fear I don't have any other suggestions. It sems each non-working heater needs to be opened up and fault finding carried out.
The problem here is that an engineer's call-out charge, hourly rate, and the likely cost of spares (and finding them), it likely to be considerable. For this reason you may find you will only be able to get quotes for replacing the heaters, as many may consider the 'repair' option is so unpredictable, they won't want to risk losing money!
This is where a DIY repair (by someone competent) is probably the only economically viable option!
"...On my visit as well as discussing the work you require I will also need to look at the existing fuse board. Two other things again we need to check is your water and gas (or oil) bonding. With them being metallic pipes rising from the ground these can carry an earth potential, we need to ensure they have the necessary earthing cables and clamps and run back to the Main Earthing Terminal, again this should be at the fuse board. Sometimes it is not always possible to confirm these 100% of the time but will give us a good idea of what's going on. With the need of having to look at these items (Fuse Board, Water & Gas) it would be good if anything stored in the same cupboards as them were removed so we can get the best view possible...."
I understand the fuse board needs to be checked but the water and gas pipes ( I do not have gas anyway)? Ok I'm not an electrician so is it a standard thing? The electrician wants to come have a look, assess first and next will give me a quote. I thought that when he comes he at once would be able to at least check and if necessary replace the fuses but the switches next to each heater, it seems like a small job (if that needs to be done). I also offered to buy some parts still available on ebay - you had suggested but have not beard about it. It would be more efficient if "simple" things which might casue the issue could be fixed at once, wouldn't it? I am just worried by this email that it already sounds like a huge job...