my baxi combi boiler hot water tap keeps running hot then cold it wont stay hot constant its only 3 years old?

Question

baxi 105e

Answer 1

It is most likely to be the diaphragm in the diverter valve, they become slack after a period of time. When you turn on a hot tap the differential pressure on the diaphragm pushes a pin which in turn switches a microswitch, the microswitch "tells" the boiler to fire up and heat the water, if the diaphragm is slack the pin won't make constant contact with the microswitch.

Answer 2

is the pump running? you should have a pump on the hot water side doing recirculating.

Answer 3

try limescaling your pipes, my water was cloudy and running hot and cold and it was simply limescale build up. hope this helps. xx