"Jon" wrote in message
oups.com...
I'm new to all this so please bare with me...

I'm having a problem with a combi-boiler and need help trying to
identify the problem -

The boiler appears to be working fine - i.e. it's able to heat the
radiators and water. However when heating water for the shower it seems
incredibility sensitive to changes in water pressure, if someone were
to turn the tap on in the kitchen the hot water flow in the shower
completely stops. Also, if the heating is on it seems to frequently
cause the hot water in the shower to fluctuate.

I'm wondering is it possible to control the boiler so that it gives
priority to heating water? Also, is it possible to prevent the affect
of turning on a tap in another room?

As the combi depends on a constant flow of mains water to heat up then it's
not easy to balance out changes to the water pressure due to
someone/something else using the water supply. Unless you have an elaborate
mechanism of storage tanks.

All you can do is to make sure you have a thermostatic mixer on your shower,
so if the water pressure drops, at least the temperature shouldn't fluctuate
too much. I know with my combi when someone else uses the water the pressure
drops equally across the hot and cold.

As for the heating, then I don't believe it should do that at all.