No hot water - please help

[alanyaber]

Hi

I have ravenheat combi boiler (RSF100). The central heating works fine. However, there is no hot water. When I turn the hot water tap on, nothing happens i.e. the pump does not turn, the fan does not switch on, no ignition, etc.. all I hear is just the flow of water. When on the other hand I switch on the CH, all works fine i.e. fan starts, pump switches on, ignition light on, firing up etc..

Any ideas on likely problem and solutions??

Thanks in advance

 

[BDL]

How old is the boiler?
Has it been serviced recently?
May be flow switch or thermister related

 

[alanyaber]

Thanks for the response. The boiler is about 3 years old and it has not been recently serviced. If you susbect the flow switch, why does the CH work fine?

regards

 

[BelgraveHeating]

The flow switch senses when your running hot water and tells the boiler to fire up.This has no connection with the central heating system, which is completely separate.

 

[alanyaber]

Thanks Belgraveheating. I susbeceted the flow switch and I am planning to switch it with that for CH. The microswitch works fine only if I manually press the tiny button. Can you explain how the three way valve operates please. Does it have a lever which pushes against the microswitch when water flows? how can I test the three way valve without removing it .

Thanks