Intermitant temperature in shower All aspects of plumbing questions and answers, help, tips and information

[phill 45]

I am having problems getting constant heat through my shower. I have a worcester 24cdi combi boiler which feeds the taps fine but will not with the shower. It starts off ok but soon turns cold, I have made sure the boiler pressure is above 1 bar and that the temperature is not too high ( to prevent it cutting out). Apart from that i am running out of ideas. I have only been in the house a week and i am still finding my way around!

[cyclop.orangehome.co.uk]

is your shower mixer compatable with a combi boiler?If your boiler was connected to an old mixer unit where there was no compensation for large variation between hot and cold inlet pressures then you wont get steady temp at the outlet.If this is the case you could try two things-fit a new mixer valve or fit a pressure reducing valve on the cold feed which would be the cheaper option.I have come across an old NEW TEAM mixer valve displaying similar symptoms and in this case a pressure balancing valve connected to both hot and cold feeds was at fault.Hope this isn`t too much info.

[htg engineer]

if the flow to the shower is restricted the water may not be getting away from the boiler quick enough, so the thermostat will cut the boiler off until it cools then bring it back on.

Check the pipes for valves that may be slightly closed, possibly remove any unnecessary valves to reduce the friction. Change flexi hoses for copper pipe.

If this fails to solve it - it could be the hot water sensor on the boiler.