Shower not getting hot

[crisby01]

Hi, hope someone could help me...

I have a combi boiler which is about 15yrs old - saunier duval SD623 - and what i think is just a mixer shower - mira 415 - approx 3yrs old.

When i turn the shower on the boiler doesn't fire up so no hot water comes out. All the other taps in the flat work fine. I have to turn the hot water tap in the bathroom to a mid flow to get the boiler working although it eventually cuts out after about 3 mins.

I am frustrated as all the other hot taps work fine! is it the boiler or shower? I am thinking of changing the boiler for a British Gas recommended BG330+, would this be cost efficient?

Thanks
Chris

 

[andytheplumber]

If all the taps are working fine than it sounds like the shower. You say the boiler is 15 years old. If you decide to change the boiler i would change the shower to.

 

[liverpoolboy]

there may be some grit in the shower cartridge? try cleaning it out.

 

[mickyg]

if the water valve is worn then the flow in the shower might not be enough to operate the microswith, whereas the tap might have a higher flow. Move the lever on the front of the boiler to the middle position(in between summer and winter) and test it. If it now works, you need a new water valve. Its a fairly straight forward and uncostly job.