Worcester (British Gas badged) R532i oddness

[NotJethroTull]

Hi, first time poster here.

Have had a recurring issue with hot water recently, manifesting as follows:
Turn shower on, it gets hot, then goes cold then gets hot and repeat. During this cycle, the boiler water temperature indication goes up to 99, drops to 50-odd, goes up to 99 etc.
Have read that this is most likely the heat exchanger plate being full of crud. Also happens when we leave the hot water tap on.

The oddness is that we’re also experiencing pressure loss - between half a bar and a bar - each day.
I also feel like the shower temperature control isn’t reflecting the temperature of what’s actually coming out.
Boiler overflow been checked and no issue from there.
Engineer has been out three times and of course the fault has not occurred when he’s been here - sealant been put into system in case of leak (nothing clear and obvious around the house).
Any advice would be absolutely welcome!

Cheers

 

[ianmcd]

sounds like the plate heat exchanger is blocked and adding leak sealer will have made it worse

 

[NotJethroTull]

Thanks Ian - very much appreciate the response.

 

[ianmcd]

Thanks Ian - very much appreciate the response.

Your best bet is to get a Worcester fixed price repair, excellent value for money and you will get a warranty