No CH

[charlietheduck]

Hi

I've just moved into a new house with a gravity-fed hot water cylinder and a Potterton Suprima boiler and the HW is fine but I have no CH at all. None of the pipes to the radiators warm up. My question is, if the pump (Grundfos 15/50) is hot, does that mean it's working? It doesn't seem to be making any noticeable noise. There is also a Sunvic Motorised Actuator Valve too. But I don't have a clue how to tell if this is working either. Should they be noisy?

If I have HW, does that mean these must be working OK and that there is some other problem, or are they only used for the CH?

Sorry to ask such a basic question, but it would really help if I had some idea what I'm talking about before I ask a plumber out (being blonde, female and in my twenties I am prone to people ripping me off!)

Thanks

 

[Agile]

It sounds as if the pump is seised up.

Its sometimes possible to free it up if you have a selection of screwdrivers and dont mind getting a little wet with dirty water.

Look at the FAQ section for details.

If you call out someone then check the prices first. The pump will probably be retrievable by spinning it but it might need to be replaced and probably the valves as well if its an old system.

We would charge a diagnostic fee of £84 which would include a boiler service if spinning the pump gets it going again. Extra £60 for new pump plus £12 if we had to replace the valves.

Tony

 

[charlietheduck]

Thanks Tony, my dad did suggest giving it a bit of a tap with a hammer to get it going again but I'm too nervous to do that!

I've read the things about unscrewing it on some other posts. If I feel brave enough this weekend, I'll have a go.

I don't think the actuator valve is very old because there's another one exactly the same in a box at the bottom of the cupboard, so it must have been replaced relatively recently (on the manual in the box it says 2002).

Anyway you've answered my basic question, which is really what I wanted to know - whether or not the pump has anything to do with the HW working. Obviously not!

Thanks very much for the prices too - it's always good to know what's a fair price to pay. Doesn't sound too extortionate so might be worth getting a pro in anyway.

 

[RigidRaider]

If the pump is running the key could be that motorised valve. Can you get close to it while switching on the heating? Turn up the roomstat to very hot then switch on the heating - you should hear the valve motor react with a sort of "zzziiizzz" sound. You should also see a little lever on the side moving. If it doesn't, you can move the lever manually and lock it in place by hooking it over a little step in its slot. The sound of the pump may change and you might hear water beginning to circulate, as well as feel the pipework warming up.

Do the radiators now warm up? If they do, your motorised valve needs a new motor, not a difficult job to do if you're handy with the toolkit. The plumber's merchant will probably warn you that if the new motor fails to solve the problem, they won't take it back. They will advise you to consider replacing the entire valve, which doesn't cost a lot more. However I believe that these motors do sometimes fail and it's seldom the actual valve that's jammed.

Let the forum know how you get on.

 

[charlietheduck]

I've just turned the dishwasher on and put the heating on and the thermostat right up and the tank started making a bit of a noise so I had a look, and now I think the pump definitely is working. I put my ear up to it and could hear a definite whirring sound. It's quiet though. But there's obviously something going on in there. And I can hear water flowing too.

As for the valve, the only lever I can see is one that says 'Normal use' on one side and 'Flushing only' on the other. Is this the one I should move? It's on Normal use at the moment. The valve itself feels as if it is vibrating slightly when I touch it. But the lever's not moving.

This is all very interesting!

Oh one last thing - the pipes in the cupboard around the tank and the pump and the valve are all hot, except for the one pipe that is coming out of the valve and going down through the floorboards...It's only lukewarm...

 

[Agile]

Have you made sure that the rad valves are all open ???

Tony

 

[RigidRaider]

Ooer - I'll leave that valve to the experts!

The pump will be almost silent.

Stupid question - you've just moved in? Summer has just ended so are you sure the radiators are actually on, ie the valves open at both ends? The non-adjusting ends should have a plastic cover, which you can pull off. Get an adjustable spanner or pliers or use a knob from the other end and check the spindles are all fully unscrewed anti-clockwise.

Edited: Must learn to type faster!

 

[charlietheduck]

No, I haven't checked the radiators, only adjusted the heat setting thing on one end of them all to be on the highest

I just assumed that most people don't turn their radiators off at both ends in the summer do they? I never have...unless I'm taking the radiator off to decorate or something...

The dishwasher has stopped getting water now and the pump is now silent too..and the valve...

Maybe the guy who lived here before did close all the radiator valves. I will check them all now!

Thanks so much,
Daft Blonde

 

[charlietheduck]

Well it can't be the radiator valves. As far as I can tell, they're all open. And the radiators downstairs are all boxed in anyway, so I can't get to the controls without ripping the boxes off the walls.

But anyway wouldn't the pipes coming up to the radiator valves through the floor get warm, if there was water attempting to get into the rad? All the radiator pipes are stone cold.

Getting really frustrated now. This is so weird.

Guess it's time to call in an expert...

 

[RigidRaider]

I'm suspicious about this spare valve you have in a cupboard. That's not the kind of thing people normally leave lying around a house when they leave. Is it possible the vendor was planning to change the valve but decided not to bother?

 

[charlietheduck]

No it's an old one, looks a bit bashed up. So obviously they replaced the valve and put the old one in the box and left it there. Guess if it's broken before then it can go again though.

I just don't understand why the valve and pump kicked into life when I put the dishwasher on!

Unless the valve didn't work, it just felt like it was cos of all the humming and whirring going on with the tank and the pump. They're all squashed into a small cupboard.

I can only think it's a problem with the valve. Are there any other things I can check? I think the thermostat and controller are OK.

Thanks for all your advice!

 

[charlietheduck]

Just to make things more interesting, I tried turning off the HW and the CH and then turning only the CH on, and now the bloomin' CH is working and the radiators are all heating up!

Don't want to turn the HW back on yet as my house is warming up nicely now! Any ideas why this would happen? Does this prove it's a valve problem?

Sorry for all the posts

 

[ChrisR]

Quite often Motorised valves are wired up wrongly, probably about 20%!
What type valve is it? Lots of Sunvics. Is there a lever on the end/side, which is springy if you push it when everything's off?
Are there two screws on the corners which would let the head be removed?
WHat shape is the brass bit - T shape (3 port) or just 2 ends?

 

[charlietheduck]

Thanks for your post Chris.

it's a Sunvic SD2701 - with three ports. Does look like it's got two screws either side too but the lever (that I described earlier) at the top isn't springy...

Hope that helps!