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Heating off but radiators hot?

(11 Posts)
rubybleu Mon 22-Dec-14 09:05:58

Before I call in an engineer - last night when we turned the heating off, it didn't/wouldn't turn off despite manually doing so. It ended up running all night. We have a condensing boiler with a hot water tank and storage tank. Boiler was installed in January 14 by the previous owners of our flat.

When my other half took a shower this morning, it appeared to to turn off but fired back up when he finished. I've just had a fiddle with the Honeywell controls near the boiler and turned the hot water off and on manually which seems to have solved the problem.

I am new to central heating (grew up in Australia) so does this sound like a controls fault and if so, who do I call? Can a gas engineer sort this out?

LL12 Mon 22-Dec-14 09:18:38

May be wrong but it sounds like your diverter valve may need a new motor.

rubybleu Mon 22-Dec-14 09:37:51

Silly question - where might the diverter valve be located?

Thurlow Mon 22-Dec-14 09:41:54

I agree, we had this a few years back and whenever the hot water came on it sent it through the radiators as well. I don't think it's something that you can fix yourself as you need to actually replace a part, but I think it's quite standard.

LL12 Mon 22-Dec-14 12:38:57

It's normally a small square silver box near your pump with a little leaver underneath it.
We had this issue a few years ago and my plumber uncle said to unscrew the cover and replace the motor which was a little round silver thing with 2 wires coming from it.
We took a picture of it before removing it so that we could just copy the re wireing with the new one. The motor cost about £18.

LL12 Mon 22-Dec-14 12:41:11

It was very easy to replace the motor ourselves, my uncle had sais that a lot of plumbers would say you have to replace the whole thing which would cost a bit and not something we could have done ourselves, when quite often it is just the motor that needs replacing.

PigletInABlanketJohn Mon 22-Dec-14 13:57:09

I am on my Tablet, but if you go to the Screwfix site and search "port valve" you will see examples. Yours is most likely a 3-port valve. It is made in two parts, a brass "T" shape and a rectangular plastic or metal box containing the motor and with a thich flex coming off it.

Either of these parts might be faulty. Yes, it is quicker to change just the motor but no good if it is the valve that is worn out. If you have to buy a complete new one, get a Honeywell or Drayton. They usually last about 20 years. If you are lucky it will be visible next to the boiler or cylinder and can be changed as a standard part by any plumber. If you are less lucky it will be integrated inside the boiler and will need a special part fitted by a heating engineer.

If you want to try fixing it yourself, start by taking off the motorised head and turning the spindle with your fingers. It should not need pliers. Do not disconnect any wires at this point, but turn off the electricity as the controls are at mains voltage. There are about 7 coloured wires in the flex. If you see a make and model number, write it down.

For the moment you can manually control it by switching heating and hw off at the timer.

LL12 Mon 22-Dec-14 14:04:38

Oh PigletJohn, wonder I could ask you a question about 3 way valves pls.
My friend has a problem with hers but I wonder if you could help? When the HW only has been on the motor on the valve turns off and cools down when the HW turns off however if she has just had the CH only on, when it turns off the you can still 'feel' the motor on and the motor stays hot until she manually switches the valve off and on by the fuse switch.
You can then hear the valve move and switch off.
Any ideas on what the cause is? maybe wiring or motor?
It was a bit of a dodgy plumber that fitted it.

PigletInABlanketJohn Mon 22-Dec-14 14:17:36

Probably it is jammed or worn out. As well as a motor, the head contains a switch that turns the pump and boiler on and off. It does this when the motor has driven the works to the position required, as directed by the two thermostats.

If it used to work properly and eventually failed, it is probably worn out. If it has never worked properly, it may have been incorrectly fitted. As I mentioned, there are a lot of wires that need to be correctly connected.

LL12 Mon 22-Dec-14 14:34:12

Thanks PigletJohn, it worked fine and then she needed a radiator changed and the plumber said she should have a new valve fitted, being on her own she believed him although not sure why as there was nothing wrong with the old one.
It's been like this for a couple of years ever since he changed it but she didn't want to call him back, she says that every time she has had her CH on she has to remember to switch it off by the fuse after it has turned off as she is afraid the motor will overheat. (The radiators and boiler switch off ok, it's just the valve motor that doesn't)

PigletInABlanketJohn Mon 22-Dec-14 15:19:29

Find someone more competent, by local recommendation.

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