Shower problem

[CITIZEN PETE]

I've had a new bathroom fitted but the shower has stopped working after a few days its powered by a Worcester bosch 29cdi combi boiler which is around 18 years old ,all the hot water taps all through the house work well , the shower works if the central heating is on has anyone got an idea of whats wrong ?
thanks in advance....Pete

 

[Madrab]

When you say it's stopped working, do you mean the water runs but it just doesn't get hot, though it does go hot if the central heating is on?

If so that'll be the boiler and it needs looked at, possibly a diverter/plate problem.

 

[CITIZEN PETE]

All the hot water taps work fine and yes we only get cold water through the shower unless the central heating is on
Thanks for replying

 

[terryplumb]

Check the filters in the shower valve. What type of shower valve is it , horizontal bar type ??

 

[CITIZEN PETE]

Yes the horizontal bar type , its brand new though ......thanks

 

[terryplumb]

Plumbing work done in advance of the valve being fitted / new bathroom fitted can result in impurities being present in the pipework finding their way to the shower valves filters. That then causes a restriction to the flow rate ,and the boiler will not fire up.
Check the filters.
If they are clean ,then the boilers suspect.

 

[durhamplumber]

If they are clean ,then the boilers suspect

Why if all hot taps are fine?

 

[terryplumb]

Why if all hot taps are fine?

Taps give a greater flow than horizontal bar mixers ,and will trigger the boiler into action ,if the boilers flow sensor / hall sensor or turbine ( whichever are applicable to the op's boiler) are not functioning to spec.
The shower may not.
It would be unusual for a thermostatic shower ,in good order, to not give sufficient flow to trigger the boiler , if the boiler was in good order.

 

[Madrab]

Could also have a restricted plate which isn't giving enough flow through the boiler to trigger the flow switch, OP are you in a hard water area?

The fact it works ok when the CH is running also points towards the fault possibly being at the boiler.

 

[CITIZEN PETE]

Not in a hard water area , when the shower is turned to full hot water it still doesn't work