Replacing zone valve

[MrCow]

Hi,

Wondering if any of you chaps can offer some pearls of wisdom

I have a sealed/closed system with 3 zones - upstairs/downstairs heating and hot water.

The downstairs zone valve has become too stiff for the valve head (drayton ZA5) to close the valve fully. As such whenever downstairs heating or hot water calls for heat from the boiler, the sticking valve is allowing water to enter that zone undesired.

I have been trying to sort a plumber out to fix but they are reluctant to come out given the current situation, understandably.

So not knowing how long this is going to go on for I have sorted out the same replacement valve and head assembly and I would like to have a crack at this myself. I am not too bad plumbing wise and can do the basics, but this is the first time i've dealt with a zone valve. Does the below sound about right?

• Isolate electrics
• Open all zone valves manually
• Drain system using drain cock on a downstairs rad opening all rad bleed valves
• Remove faulty zone valve
• Fit new valve
• Close radiator bleed valves
• Add inhibitor to one rad
• Repressurise and bleed off
• Put zone valves back to auto

I notice all my downstairs radiators have a drain valve, do I need to drain using all the downstairs radiators or can I just drain from the most convenient i.e the back door.
The existing valve uses compression fittings (22mm). Can I reuse the existing olives if I can't remove them or should I use new ones? Will 22mm brass olives fit and be OK for 22mm copper pipe?

Anything else I should be aware of or should I really just leave this to the pro's?

Thanks

 

[ianmcd]

you might not need to do all that , remove the problem actator and using an adjustable spanner, manually vove the valve back and forth and see if it frees off, they can get to a situation where they need replaced , but that is unusual, more likely to be a faulty synchron motor, if the valve frees off just change the actuator, no need to drain down anything

 

[MrCow]

Yeah, I tried removing the actuator. The valve is difficult to turn by finger compared with the other zone valves which rotates very freely. I can free it up slightly by opening/closing a few times and it works fine for a couple of days but then starts sticking and allowing water to pass again. I'm 100% sure it's the valve starting to seize up and not the head.

Like you I am surprised it's going so soon, it's only about 5 years old. Other valves are fine though, must be a duffer.

Thanks for the tip in any case

 

[ianmcd]

Yes have seen it happen before but it is not the norm, Drayton arent great in my own opinion, I always use Honeywell, but the "equivelent" are cheap rubbish, if your system is a sealed system you will probably get away with just dropping the system pressure and using good sized towels, no real need to drain everything, but if you feel easier draining it all down, yep add a litre of inhibitor and re-fill, you need to turn everything off and open the manual levers on all the valves when re-filling , that is what they are for