Changing Motorised Valve

[AnonymousImport]

Hi There

Would you recommend changing the motorised valve yourself or getting out a plumber? I've got a 2 Port valve that keeps sticking so sometimes we get roasting radiators and boiling water and other times we get nothing (irrespective of what the thermostat says)!

The current valve is apparently 20+ years old (honeywell) and I've been told that the new 2 port valves are not compatible with the older ones - is this true?? Any help would be greatly appreciated.

Pam

 

[AnonymousImport]

Depends on your plumbing ability. To help you decide, consider the following:

You will need to completely drain down your heating system, carry out the work, and refill it, venting the radiators, getting rid of any airlocks in the pipework etc.

You will need to remove the valve, you may need to disconnect (or cut) several pipes to get enough slack to get the valve out. You will need to make good anything you disturb.

The new valve may have slightly different dimensions to the old one, so you may need to make up some new pipework to suit it.

You will need to figure out the electrical wiring to the old valve motor,make it safe to work on, and connect the new one correctly.

If you are confident to do this, then go ahead. It is not that difficult. Make sure you have a few feet of pipe the right size (22 mm??), several fittings, all the tools you require, and plenty of time before you start the job. Allow for surprises or problems. Remember you will have no heating until you finish the job. You will also have no hot water, unless you have an immersion heater. Best of luck and let us know how you get on.

 

[PamPaul]

Thanks for that "Anonymous" (PS - I'm the anonymous who started this thread)!

You're right about the dimensions of the pipework - the new valve connections are smaller than the old ones.

As for draining the system - I know how to do that (and I'm blonde)!!

The only problem is I have two radiators that I am unable to bleed as the "thing" is no longer square so can't get a grip on it with the key. Any ideas??

[Edited by PamPaul on 29-11-2002 at 15:14 PM GMT]

 

[AnonymousImport]

Re the problem radiators, I'd suggest that you close the valves on BOTH sides of the radiators - the handwheel valve and the lockshield valve (this one may have a cover over it) That way, you shouldn't get any air in when you drain down.
Make a note of how many turns you need to close the lockshield valve, and put it back where you found it when finished, its purpose is to balance the water flow.
When you are re-filling, get all the air out of the pipes and other radiators before you turn these two back on.

The new valve connections should be the same size as the old ones, although the distance between them may not be the same. If you replace say a 28 mm motorised valve with a 22 mm one, you will reduce the flow to the radiators and may upset the operation of the system.