I have got a small glow worm boiler (dont know model as it doesnt say anything) It is about 7 years old (when house was built) and controls hot water and the central heating (5 radiators) on a timer (hot water automatically comes on when you turn on the hot water tap) or it should do! Here is where one of the problems is.

If we turn on any hot water top we will get a stream of hot water for a few seconds and then it goes cold. We then have to run it for a while to get warm (not good as we are on a water meter). We can reduce the flow from the taps and this makes the water go hotter quicker (okay for the downstairs sink but when you are running a bath it can take about 30+ mins to get decent temperature).

Also and this is probably related, the pressure on the boiler does drop and probably needs me topping up every 2 weeks or so (by a stop tap under the sink). When in operation the boiler is also very noisy, we have had a british gas engineer out now 3 times and the last time he did manage to sort the noise out by lubricating something ( i wasnt in at the time it was my future mother in law so she didnt ask what it was that he had done) however it has now returned.

Finally, the radiators only seem to have 2 settings, on or off. They all have valves on them with a setting from say off to 5 but nothing happens in between off and 5. The radiators did have air in them which I have bled off but within a few days it sounds like air is back in the system.
There isnt any expansion tank or anything in the loft.

Anyone any ideas before I get BritishGas out again (dont really trust them as they have been out 3 times now and not sorted it)

It sounds like you have two problems, the first is most likely the diverter valve sticking and the second is a leak or air being drawn in through a leaking joint hence the constant topping up. Both probs really need a competant CORGI Engineer.

Mog

Finally, the radiators only seem to have 2 settings, on or off. They all have valves on them with a setting from say off to 5 but nothing happens in between off and 5
Are these thermostatic valves? If so, turning them to, say 2 or 3, should mean that the rad goes cold once the room temperature reaches around 18-20 degrees Celsius. If that isn't happening, it sounds like they are faulty. I've just had to change one of my old Danfoss ones as it refused to shut fully, even when screwed down tight, so the room was FAR too hot.

If they aren't thermostatic, they have two settings, on or off.

Alcazar

Are these thermostatic valves? If so, turning them to, say 2 or 3, should mean that the rad goes cold once the room temperature reaches around 18-20 degrees Celsius. If that isn't happening, it sounds like they are faulty. I've just had to change one of my old Danfoss ones as it refused to shut fully, even when screwed down tight, so the room was FAR too hot.

If they aren't thermostatic, they have two settings, on or off.

Alcazar
How can I tell? They are just cylinderical valves with setting of off which is indicated by a white circle, then settings as follows I II III IIII and then a black circle which is maximum. Only comes on on the maximum!

It sounds like you have two problems, the first is most likely the diverter valve sticking and the second is a leak or air being drawn in through a leaking joint hence the constant topping up. Both probs really need a competant CORGI Engineer.

Mog
Found a very small leak, where the pipes go into the boiler (think there are about 5) a few of the pipes have little taps type things on them. One of these has a minor leak so that is probably why I need to top it up and could explain the air in the system.

What does a diverter valve do?

Your valves SOUND like TRVs, but I can't tell why they shouldn't work except at full on setting............unless your house is really warm? In this case, the valves will be closed (by the house temperature being high) until they are set at a temperature HIGHER than that of the house. I suppose you could try turning one fully off, closing the door of the room it's in, and opening all the windows to let the room cool right down. Then go back in, shut the door behind you and turn the valve back on at "I" setting, and see if anything happens.....does the rad start to get warm? Then try "II" etc. I suppose the thermostatic heads could be faulty? Dunno, really, my experience is that the heads are foolproof, it's the valve part that causes probs, sticking open, shut etc etc.

A divertor valve is used in a fully pumped sytem, where only TWO pipes come out of the boiler. The valve is used to decide whether the heating, the hot water or both, get the boiler's output. They tend to be prone to problems........

Alcazar

A divertor valve is used in a fully pumped sytem, where only TWO pipes come out of the boiler. The valve is used to decide whether the heating, the hot water or both, get the boiler's output. They tend to be prone to problems........

Alcazar

You are right when talking about a conventional system but he has a combi and the divertor valve is internal to the boiler and diverts the heated water to the central heating heat exchanger or hot water heat exchanger and so if the valve is stuck or sticking then hot water won't be available.

Mog

You are right when talking about a conventional system but he has a combi and the divertor valve is internal to the boiler and diverts the heated water to the central heating heat exchanger or hot water heat exchanger and so if the valve is stuck or sticking then hot water won't be available.

Mog
Ah.......OK, thanks. It's doing a similar job, but in a different way?

Alcazar