unhandymann
DIY
90s house electric issues continues 
So after getting some good advice here I've managed to sort out some of the heating issues so thank you for that everyone
I'm seem to have a few bugs and keep chasing problems
So my current issue is downstairs shower only has hot water with no power to the pump.
Bath and basin both working fine.
I've taken off the cover and checked the feed has plenty of cold water that's no problem.
I've checked the mains and not getting 230v from the main supply.
Now being an early 90s I don't think it has a fuse link like the 2 upstairs shower with the little red light near the units.
If searched high and low and doesn't seem to be one anywhere nor an individual fuse on the board.
Using a multimeter I've established its getting a tiny feed of power (0.622v) when 2 of the circuit breakers are ON, both seem to feed power to the unit, flick one on I get the (0.6v with with either)
Here's my readings with all mains on
Negative probe to earth (ac)
(N) - 0.566v
(L) - 0.622v
Earth to Negative - 0.0558v
Is it possible I have a faulty mains circuit breaker or one of the board breakers?

So after getting some good advice here I've managed to sort out some of the heating issues so thank you for that everyone

I'm seem to have a few bugs and keep chasing problems
So my current issue is downstairs shower only has hot water with no power to the pump.
Bath and basin both working fine.
I've taken off the cover and checked the feed has plenty of cold water that's no problem.
I've checked the mains and not getting 230v from the main supply.
Now being an early 90s I don't think it has a fuse link like the 2 upstairs shower with the little red light near the units.
If searched high and low and doesn't seem to be one anywhere nor an individual fuse on the board.
Using a multimeter I've established its getting a tiny feed of power (0.622v) when 2 of the circuit breakers are ON, both seem to feed power to the unit, flick one on I get the (0.6v with with either)
Here's my readings with all mains on
Negative probe to earth (ac)
(N) - 0.566v
(L) - 0.622v
Earth to Negative - 0.0558v
Is it possible I have a faulty mains circuit breaker or one of the board breakers?