no domestic hot water Valliant turbo 242

[cousinjack]

Hi

My combi boiler has stopped firing up when the hot water tap is turned on.

It works fine on central heating, and once the CH is working then hot water is available but it does not go thro the routine of shutting down and refiring for DHW as it should do.

I have been told that this a a diverter valve problem but I am a little unsure if this is true.

It seems to me that there should be something that detects a fall in presure as the hot tap is turned on, and and that this causes the boiler to go into DHW mode... is this the Pressure Differential Valve or Servo Valve ? or is the problem really the diverter valve (this .. of course is the more expensive item !!) thanks for any advice you may give

 

[ChrisR]

Turbomax (VUW) 242 does not have a Pressure Differential Valve for HW or a Servo Valve. Black plastic panel, bright green knobs

Are you talking about a VCW242? Two square gauges, built like a tank...

 

[cousinjack]

Turbomax (VUW) 242 does not have a Pressure Differential Valve for HW or a Servo Valve. Black plastic panel, bright green knobs

Are you talking about a VCW242? Two square gauges, built like a tank...

I have phoned to check details as I am not at home at present.

It is turbomax 242e and has green kobs plus a round dial with water temp and pressure shown .. pressure is 1.5 bar as reqiured.. running on bottle gas.

When I fire up the CH I can use the DHW absolutely as normal, except that the boiler does not shut down and reignite like it should and that the light for DHW is not illuminated.

What actually causes the system to fire up when DHW is demanded? In my own uninformed mind I assume that there must be a device that checks for flow or presure drop and this kicks the thing into action ?


Any help would be great

Ta

 

[cross thread]

domestic diaphgram in bottom of diverter valve most likley.but small lever arm it moves can snap. fiddly to change