Vaillant 242e Combi - No central heating but hot water okay?

[b16sne]

Hi, thanks for taking the time to read this.

I've got a problem with a boiler (Vaillant Turbomax 242e Combi) - the hot water is fine when you turn the tap on but when you switch the heating on at the boiler, it fires up (fan and pump runs) but then stops about 10 seconds later. I've been told that it maybe the diverter valve, but thought I'd get some good advice off here first. Any ideas?

Thank you

Steve

 

[mikegas]

does it fire up for ch at all?

 

[b16sne]

does it fire up for ch at all?

Hi Mike, yes it does but only briefly. I seem to think its some kind of thermostat problem but I'm probably wrong. I've trauled various forums and they seem to suggest the diverter valve - all be it a lot of the problems that they are describing are having central heating but no hot water....which is the opposite to problems I've got!

Steve

 

[Billy Bob Bob]

its not the diverter timeclock,room stat,ch thermister or pcb problem

 

[b16sne]

Timeclock was replaced not that long ago, there is no roomstat, so hopefully its the thermister - I'll start with the cheapest! Are these easy to replace?

Thanks for the replies.

 

[Billy Bob Bob]

Timeclock was replaced not that long ago, there is no roomstat, so hopefully its the thermister - I'll start with the cheapest! Are these easy to replace?

Thanks for the replies.

depends on how competent you are,would strongly recommend the timer is checked first regardless of how young it is

 

[b16sne]

Is there a way of checking the timer? Also do you need to drain the system to fit a thermister? Thanks for your replies gas man....much appreciated.

Steve

 

[Billy Bob Bob]

yes on draing the system is your timer remote? or built in to the facia

 

[b16sne]

yes on draing the system is your timer remote? or built in to the facia

Built in. I don't understand why it would fire up when you switch the control to heating and hot water, but saying that when you turn the timer to the time it should come on, it doesn't do anything. I suppose logic is saying the timer?!

 

[Billy Bob Bob]

look round the back of the clock what colors are they buy this point can you use a multi meter?

 

[b16sne]

Hi, couldn't tell you what the wires are coloured as the boiler is at another property. I can sort of use a multimeter lol........

 

[Billy Bob Bob]

not sure they differ from brand to brand should have brown,blue,and 2 blacks but they varies alot

 

[b16sne]

I'll check it out, may just get a replacement just to be sure (aswell as a thermister!) I really appreciate your time, I'll let you know how I get on. Thanks again!

Steve

 

[tackleburger]

depends on how competent you are,would strongly recommend the timer is checked first regardless of how young it is

It's not a thermister. I'd agree and say its a diverter problem if it's not the timeclock . CH thermister problem would be apperent in hot water mode.

 

[b16sne]

It's not a thermister. I'd agree and say its a diverter problem if it's not the timeclock . CH thermister problem would be apperent in hot water mode.

Well at least we've kinda narrowed it down! I'm going to get hold of both, I'll replace the timer first then if no luck then the diverter valve. I'll report back either way.

Many thanks! Steve

 

[beneyresgas]

check your NTC sensor?