No hot water but CH works (Vaillant Ecotec Pro 28)

[werebeef]

My house has a Vaillant Ecotec Pro 28 combi boiler. Our hot taps have just started running cold. The boiler makes all the usual sounds and steam leaves the vent when the hot taps are turned on - but the water coming out is cold. Our heating still works but the one rad in the house without a control seems to be running full tilt, turning that particular room into an oven. Any help would be appreciated.

 

[Agile]

With the heating off, if you run water for five minutes do the radiators get hot?

If so then it indicates a diverter valve failure!

But not really a DIY job because the boiler case is the combustion area seal.

Tony

 

[werebeef]

With the heating off, if you run water for five minutes do the radiators get hot?

If so then it indicates a diverter valve failure!

But not really a DIY job because the boiler case is the combustion area seal.

Tony

All radiators seem fine except one that wants to stay hot 24/7.

Someone else mentioned diverter valve issues when I asked about their previous boiler troubles.

I don't intend to tackle it myself - just trying to get the tiniest bit clued up before getting someone in!

 

[Agile]

With the heating off, if you run water for five minutes do ANY radiators get hot?

Tony

 

[gigz]

From cold, turn the hot tap on and feel the left hand pipe on the boiler. Does this get hot ?

 

[werebeef]

From cold, turn the hot tap on and feel the left hand pipe on the boiler. Does this get hot ?

Just checked and the leftmost pipe (CH flow?) was already warm before turning a tap. I ran a hot tap and the pipe did get hotter.

 

[Agile]

None of what has been said is very conclusive at all!

If you turn off the boiler power for an hour so it is totally cold and then restore the power but with no demand for heating or hot water then does any pipe get hot?

Tony

 

[jeff the gasman]

Sticking diverter valve and DHW preheat running radiators is the usual scenario with this.
Jeff