Combi Hot Water Temp. Cross leak?

[davas]

Hi forum,

Wondering if anyone can offer some advice. We’ve got a Worcester Bosch Greenstar 37i Combi Boiler. It’s about 10 years old now and we noticed that the hot water temp was nowhere near good enough for showering, running baths etc. Even at a slower rate it isn’t good enough. It’s something that has got worse over time.

Have a contract with WB so called them out this week. The guy says he replaced a few things including the heat exchangers but is basically saying the boiler is fine. He’s blaming any hot water problems on a cross leak between hit and cold feeds somewhere.

Is this a common thing or is it more likely to be a problem with the boiler?

I’ve tried isolating the mixer taps in the house but no improvement on the temp. Tried turning off the cold water feed to the boiler and the running the hot taps one at a time but nothing comes out.

Any ideas on how I can convince WB that it must be the boiler?

Many thanks

Chris

 

[shambolic]

What if it’s not the boiler? Most likely a back feee from a shower or other mixer.

 

[JohnD]

Is this a common thing

Yes

Ceramic mixer taps with a joystick are very prone to it, so are shower mixers. If you put your hand on the "hot" pipe under the tap you may find it goes cold when water from the cold pipe flows down it.

 

[davas]

Thanks for your replies. I’m open to it being a mixer but I’m just trying to figure out how I prove the boiler is ok or identify which mixer it is. I’ve isolated the chief suspect of the old shower (hole in kitchen ceiling to do that) but it seems no better. I’ve turned off a feed to each mixer we have except for the bath and a brand new shower.

The new shower Can be isolated as well but I’m assuming that is ok as the problem didn’t start when we had it installed