VOKERA 24 problems

[TKN17]

So as not to confuse this with my previous post i will add it as a new topic.

Vokera 24, after heat exchanger replacement the boiler will not operate for long when the CH is asked for (10-15 seconds) , DHW OK.

Problem seems to be that there is not enough flow through the heat exchanger which shuts the boiler down through an over temp fault. When i crack the thermistor on the exchanger there is just steam coming out, to me this backs up the lack of flow through the exchanger theory. I have removed the pump and switched the boiler on briefly , the pump spins and cannot be stopped by exerting pressure on the impeller.

So the question - what am i missing as this is driving me crazy, i even refitted the old exchanger but the problem still exists

Regards -- Kenny

 

[nickso]

Both flow and return valves under the boiler are open?

 

[TKN17]

Yes - the valves have not been touched (ever), the rads closest to the boiler are starting to get warm but as the boiler cuts out pretty much straight away so there is no time form the remaining rads to get warm water to them.

Kenny

 

[lightning]

Sounds like air in the boiler, is the aav open.

 

[TKN17]

Yes the auto air vent is open (the plastic cover has been discarded). just cracked the themister and it is still steam that is coming out, the flow and return pipes ,when the boiler is running, are starting to get warm which tells me there is some form of circulation going on.

The CH has been off for the past few months and was working perfectly prior to me fitting the exchanger. I even tried it last week and it was warming the rads without any dramas.

Confused - Kenny

 

[Agile]

The diverter valve seems to be stuck in the DHW position.

Tony

 

[TKN17]

On the compact 24 there is no diverter valve it has two seperate circuits within the HE.

Kenny