I have a mixer shower which is attached to a pump. The hot water does not seem to flow through like the cold water resulting in cold showers. When the shower is on and I switch the pump off from the mains then back on again the shower is fine.
Spoke to a bathrrom store and they have advsised recalibration is required.
Make John Sydney Brasserie Ltd (now trade under Bristan)

Amish Shah, November 2004

It could be that the cold water is being supplied at higher pressure than the hot. Hot and cold should be at the same pressure, try turning the cold water supply to the pump down slightly, if the water is hotter then you just need to balance the supplies by trial and error. Dont turn either of the supplies down too much otherwise the pump will cut out.

steve, November 2004