"chris French" wrote in message
...
In message , Mark Hewitt
writes

"Doctor Drivel" wrote in message
reenews.net...

Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.

Bzzzt Wrong. A higher flowrate combi would solve it too.

It's my understanding that Combi's can only ever supply hot water at the
maximum flow rate of the mains supply.

And/or the maximum rate at which they can heat it. The mains flow in my
old house with a combi the mains flow rate was a fair bit more than the
boiler could heat. So the rate of heating was the limiting factor (as it
is in most combi installations I suspect.

Unless you have 76kW MAN boiler

Which I think mine certainly can.

If you shower really does stop (as opposed to just get bit slower) when
another tap is turned on then it suggests to me that the mains flow
isn't up to the job maybe. In the above mentioned installation, (with a
100,000 btu combi) if someone tuned on the tap in the kitchen or the
bathroom the shower flow would reduce, but it was still usable. 15mm
water supply, bath or kitchen teed off of the same pipe to the shower.


--
Chris French