sounds like 3 way valve cartridge,solving same fault with a friends.Part easily available and straightforward for your engineer to sort.
Not Terminal!!
ok
Gauntlett, April 2008
If the boiler is not firing up for dhw when you turn the tap on, the dhw flow switch needs replacing....not a big job by any means
T, April 2008
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I can answer this question...
Boiler Glow Worm 30ci is not heating water but central heating works fine,?
