Central Heating/Plumbing - 3 way valve?

DorsetDude

DorsetDude

Spud
Suspended / Banned
Messages
7,018
Name
Keith
Edit My Images
Yes
Morning all

was sitting in my lounge sweltering over the weekend when I realised the heating wasnt calling for heat, and the radiators were too hot to touch. However the hot water was due to be on. So it seems the radiators are coming on whenever the hot water cycle is on (as well as when they're supposed to be on). I have a vague recollection of a 3 way valve that switches between hot water, radiators or both so I suspect this has broken? Am I right?
If so can I fix it myself or do I need to get my man in, who will no doubt be busy as winter starts to arrive. Also where is it likely located? Am wondering if tapping it with a hammer might free up "bits"

Thanks.
 
Often located near the pump and/or boiler. In my experience the thing that tends to go is the solenoid that actuates the valve rather than the mechanical bits of the valve itself. The Solenoid is a metal box on top of the valve with a wire coming out of it. You can usually get a replacement and fit it rather than replacing the whole valve but make sure you understand how to wire it up before you start disconnecting the old one.
 
If there's a manual over-ride lever, wiggle that from side to side - the valves can get slightly stuck after a summer of sitting in one setting and the wiggle is often enough to get things moving properly again.
 
Nod said:
If there's a manual over-ride lever, wiggle that from side to side - the valves can get slightly stuck after a summer of sitting in one setting and the wiggle is often enough to get things moving properly again.
Click to expand...
Like the sound of that. Biggest problem I have will be finding the bladdy thing. I have a "thing" in the loft where I can set the speed from 1 to 3, presumably this is the pump. Is the valve likely to be near that I wonder? And conveniently located under 18" of fibreglass. Grrrr. Hate having to go up into the loft rooting around.
 
USUALLY (but not always...) near the pump and/or hot water tank. Looks similar to the thing Jonathan has posted above. Other types can be seen HERE along with prices for the part should it need replacing. Replacing the motor is relatively easy once you know exactly which one you need (and have found the bloody thing under the fibreglass!) but getting it wired correctly is a must. Doing the valve itself is less easy and is best left to a plumber. Personally, I get a man in to do these sorts of job unless I'm 100% certain I can do it.
 
If you've a 3 way valve it maybe located near the hot water cylinder if it's not near the pump as Nod says.

Does sound like a sticky / stuck valve - other than draining it down to below this level, it's a relatively simple job to replace - if you can, try to get the same valve as you already have for simplified exchange - if you need to swap it.

Certainly worth looking to see if you can change the solenoid alone though ...
 
I had the same thing happen to me earlier this year. Rather than mess about carrying out a repair, due to the fact the valve is 14 years old and activated twice daily, every day, I decided to replace the whole valve, which was relatively simple to do. if you have some DIY skills. You do however have to drain the central heating system and when refilling don't forget the inhibiter. As already been mentioned, it is vital to rewire the valve like-for-like.

I also used the existing nuts on the copper pipe, so that it was a simple swap and took about three hours including the drain down and refill.

One word of caution when undoing the nuts, use two spanners or pipe grips to ensure you don't loosen any other fittings on the same pipework.
 
If you do decide to do it yourself then a good tip to help you rewire the new one correctly is to NOT disconnect the old one by loosening screws and removing the wires. Instead cut the existing wires near the connection screws but leave a long "tail", this will help to get the correct colours of the new wires connected to the correct terminal.
 
Suvv said:
If you do decide to do it yourself then a good tip to help you rewire the new one correctly is to NOT disconnect the old one by loosening screws and removing the wires. Instead cut the existing wires near the connection screws but leave a long "tail", this will help to get the correct colours of the new wires connected to the correct terminal.
Click to expand...

I should have added to my explanation that I didn't disconnect the cables at either the valve or the heating terminal. I simply cut of the old valve cables about nine inches from the heating terminal and just made a connection using a six cable junction box with the cable from the new valve cut appropriately. The junction box cable connection was made-up before I placed the valve in position and tightened the three nuts.

The three way motorised valve has five cables, which are all colour coded.

Another warning which I didn't mention. Turn the heating and hot water to OFF at the programer before starting work.
 
You must log in or register to reply here.
Back
Top