central heating not working

I've just moved into a house about 3 weeks ago and the central heating does not work. I've not owned a house before so I'm a real novice.
It has a gas boiler that heats the hot water and is supposed to heat the radiators too. I've had a look on the web and I think my hot water is working as it has some very large pipes which are probably working by convection/gravity to do the hot water. I think it's probably the original boiler and therefore made around 1984. It's a glowworm (I think that's right).
Seems to me there are a few possible causes
1) Water pump isn't working. Yet it has a voltage going into it and I'd expect to feel some heat in the radiator pipes coming out of the boiler just by convection but they are stone cold. On the other hand, it doesn't make any sound at all - I'd have thought you'd hear something.
2) There's no water in the sytem at all - not likley I would have thought. I'm going to try bleeding a radiator tonight to confirm.
3) Some problem in the boiler. Is there a way it could be providing hot water but no heat at all to the CH circuit?
An engineer is coming round on Wednesday to check the boiler anyway but it'd be nice to have some heating before then!
Cheers
Peter
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http://www.beluga.freeserve.co.uk

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Peter Smithson wrote:

If not it ought to be getting quite warm.... Often they seize up when not used in the summer and can be freed up by removing the large round screw cover (with a coin) and rotating the end of the shaft with a screwdriver. Do this with ch power off. There may be some water leakage when you remove the cover, its nothing to worry about but don't let it fall on anything that matters as it will stain. If the pump has burnt out, possible if it has been powered on whilst jammed, they they are fairly easy to replace as they have isolating valves either side. Get new one of equal or higher head rating (4/5m) from B&Q or similar. Obviously you need big spanner/wrench for pump connections.

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snipped-for-privacy@hotmail.com says...

I think I've just got it going! I took that screw out and although I could not move anything in there - there was just a blank plate with a very slight indentation on it. So I tried to move it but no luck. I put it back together, turned it on - nothing. So I put the speed marker up to 3 from 2 and it's making a very slight noise and the boiler has kicked in! Just checked - the radiators are warming up. So thanks for the advice everyone - this is a nice news group.
Certainly seems like I need to invest in a new system a bit later although all the radiators have those thermostats on so it's not that wastefull a system. I think the annual bill is about 100 for gas (got an electric cooker).
Cheers
Peter
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Probably the pump. Could be the zone valve, although they might not have bothered to fit one. Even if they have, the controls should have been wired so that the pump only fires when the valve is detected to be open, but they might not have bothered to wire properly.
Christian.
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As others have said, it's most likely a duff pump.
But also check: * the programmer - should be set to Heating On * the room stat - should be set to a high enough temperature * radiator valves - some fool may have turned them all off for the summer!
It's unlikely that there's no water in the system - otherwise the hot water wouldn't work. But check the small header/expansion tank anyway, and check that it's ball-valve works properly. [It should only have a couple of inches of water in the bottom when the system is cold - but the outlet in the bottom of the tank *must* be covered - otherwise air will be drawn into the system].
HTH, Roger
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news@spam_me_not37.fslife.co.uk says...

OK - I'll see if it's getting hot or not and that will tell me if it's burnt out or jammed ( I think ).

There's no room stat and there's no heat in the pipes leaving the boiler for the CH so I doubt the radiator valves so I think I'm OK there. Programer is OK - I checked it gets voltage at the pump and I presume that voltage is only there when the CH is on - I could check that to make sure it does turn it off just out of curiosity.

I've had a look at http://www.technosolution.co.uk/diy/centralheating/CHSystems/systems.htm and I see what you mean - the water for heating the hot water and radiators seems to be linked. Yet looking at my boiler with the cover off shows two thick pipes going in on one side and two thick pipes going in on the other. One pair of pipes gets hot and heads off to the hot water system. The other pair don't get hot and are linked to the CH system. So I thought they were seperate. Is that possible?
There's a picture of the outside here, I think this link will work -
http://uk.f2.pg.photos.yahoo.com/ph/pgsmithson/lst?.dir=/boiler&.view=t
the 2 pipes on the left get hot. None of the ones on the right do.
Thanks for everyones replies.
Peter
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http://www.beluga.freeserve.co.uk

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Yep. You appear to have gravity circulation. I would recommend upgrading this. The simplest method would be to add a 2 port valve, pump and cylinder thermostat. This will stop the water getting too hot, save energy and reduce boiler cycling. In the longer term, the systems can be combined when you replace the boiler with a single circuit controlled by the 2 zone valves. You then only need one pump.
You also say there is no room stat. Add one ASAP (and a zone valve if it has none) and make sure other rooms have TRVs too. You are wasting gas like it grows on trees.
Christian.
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<snip>

Slightly puzzled - I thought the OP said that all radiators had TRVs. If so, why do you need a room thermostat? In fact, which room do you put it in?
If I understand correctly, a room thermostat turn the CH off once a specific room has reached a certain temperature. At this point any other room which is below optimum temperature cannot heat up.
This leads me to deduce that the room thermostat should be in the room to heat up last and cool down first, so that all the other rooms are able to come up to temperature and then shut down the radiators via TRVs to keep at optimum temperature.
If this is correct then the remote wiring required to install a thermostat just to regulate one room seems pointless - just give this room a TRV as well.
Or am I missing something?
Cheers Dave R
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On Sat, 27 Sep 2003 11:22:40 +0100, David W.E. Roberts wrote:

To stop the boiler cycling through the bypass loop once the all the TRVs have shutdown because the house is warm. This cycling is using energy just to keep the boiler warm not the house. OK it will heat the house but it is heat which isn't required.

One without a TRV on the radiator. The hall is generally accepted to be a good place but there are almost religious debates about this from time to time. Otherwise your understanding of the implications of the room stat on system with TRVs is correct
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Dave. pam is missing e-mail
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off by a stat.
Unless, of course, you go for a Rolls Royce solution - and put a zone valve controlled by a room stat on each radiator feed - and connect all the zone valves' voltage-free contacts in parallel to control the boiler and pump. That way, you can conrol the temperature of each room independendly (like with a TRV) BUT also have the system automatically shut down when all demands are satisfied. [If you used a programmable stat in each room, you could even have different rooms heated at different times if this would be useful for your particular lifestyle].
Roger
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I am no expert, but in my recent studies I came across this
http://www.gasman.fsbusiness.co.uk/gravity_hot_water_pumped_heating.htm
which looks like what you are describing.
If it is, then you need, like everybody has said, to look at the pump.
HTH
mike r
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says...

What you've got is a gravity hot water and pumped central heating system. They share the *same* water - which gets heated by the boiler, and either flows by gravity through the indirect coil in the hot water cylinder - or by pump action through the radiators.
Pipes only get got (except for a small amount of conduction) when hot water flows through them. If there is no flow round the radiator circuit, the pipes in that circuit (the pair on the heating side of the boiler) won't get hot. You have to determine *why* there is no flow. As I said earlier, it is probably a duff pump - but it just *could* be that all the radiators are turned off - because this would effectively kill that circuit.
Roger
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