Vaillant Combi Boiler

[MTW]

We have a Vaillant combi boiler, and have two problems?? First one is the pump (I think) keeps cutting in even when the is no call for heating or hot water, continues alll through the night?? Second, two of the radiators will not get hot, tried turning all the other radiators off and leaving those two open and firing the boiler, but no good, Also tried bleeding the radiators, and no air came out. Any help would be much appreciated?? Regards

 

[whistler]

Re your first problem, Vailants have a warm start facilty which basically heats up the water in the boiler so that when you turn on the hot tap you get instant hot water. this happens every hour. You can disable this. Check your instruction manual, but on my 824 combi, you turn the hot water control completely down and then up again but stop just before the end when the gren light comes on.

 

[twgas]

is the boiler in an unheated area, causing the frost protection to kick in.
Have the checked the system pressure, then have another go at bleeding.

 

[MTW]

Thanks for the replies, will try the hot water control setting Whistler, we were having problems with the hot water last week, and may have set this by turning the hot water control all the way up and down again. The system pressure is just above 1.5

 

[MTW]

Any other suggestions re the the two cold radiators??

 

[sooey]

Second, two of the radiators will not get hot, tried turning all the other radiators off and leaving those two open and firing the boiler, but no good, Also tried bleeding the radiators, and no air came out.

Sounds like the valves are closed on both sides or they're not connected.
Have they ever worked?

 

[MTW]

Yes, they worked last year, but the one has played up before, could be the termostat vales then???

 

[sooey]

Yes the TRVs could be stuck closed, but you should still be able to bleed the rads in that case.

 

[David937]

We have a Vaillant combi boiler, and have two problems?? First one is the pump (I think) keeps cutting in even when the is no call for heating or hot water, continues alll through the night?? Second, two of the radiators will not get hot, tried turning all the other radiators off and leaving those two open and firing the boiler, but no good, Also tried bleeding the radiators, and no air came out. Any help would be much appreciated?? Regards

What model Vaillant do you have?

 

[MTW]

Just want to thank whistler, his suggestion cured the repeated firing.

The model we have is the Turbox 824.

When I try to bleed any of the radiators, alll that comes out is water, no air. Is there a easy way to free up the stats if it is that they are stuck closed??