Volkera losing pressure, pilot blowing out and variable hot Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[RosieC]

I have a volkera combi boiler - I'm not sure what make off the top of my head, though I can go and find out

It is constantly losing pressure (one bath or 3 days is enough to go from 1.5bar, the recommended pressure, to 0), so I have to keep turning the pressure tap to keep it high enough to stop the pilot blowing out

Recently the pilot light started blowing out regardless of water pressure. The hot water is also no longer constantly hot - it cycles between hot and cold (or hot, then cold, then the boiler blows out and I have to go and relight it)

Finally, for some reason, it interferes with the record player if the heating is on, though I can cope with that.

Is there anything I can do to fix it, or do I need a new boiler?

[htg engineer]

Does the pressure rise before falling ? if the expansion vessel or plate heat-ex is at fault, the pressure will rise to 3.5bar, The Pressure relief valve will open, the water will be discharged outside and the pressure will drop to zero. Which in turn will cut off the pilot - so that the boiler cannot be used.

Check the pressure gauge when the heating is on, and when you're running a bath. The hot water temperature may be sown to a faulty sensor or thermistor.

htg

[RosieC]

The pressure never rises - it just constantly goes down. I suspect there is a leak, but I can't find any obvious wet patches, although since the boiler is in the (very damp) cellar, they are a bit hard to find

[htg engineer]

Not sure what you mean by one bath or 3 days ??
If you run the bath, does the pressure drop ?
If you ran the bath 3 times in one day, would the pressure drop each time ?

Do you vent the radiators when you top the pressure up ? if you continually top the pressure up - but never vent the radiators the pressure will always drop, this is because there'll be air in the system, it'll find it's way out probably via the automatic airvent - the air that is lost needs to be replaced with water.

If all the radiators are full and the pressure still drops, then it does seem to be a leak somewhere. Check all obvious places:
Boiler, Pipework and connections
Pressure relief discharge
Radiator valves and pipework
Radiators, any rust spots or vent closed no signs of leaks

If no luck you need to start checking under the floors etc, if easily done. If you have tiled, laminate or wood flooring - that'll be a problem to lift or expensive. You could try adding leak sealer to the system.

htg