Failed Honeywell Motorised CH Valve

[Graeme]

One of our zone valves has failed in that the spring on the little lever has broken, or possibly come adrift. The lever moves across without any resistance in either direction with the result that, when the boiler is fired by any zone, the radiators in the 'unfired' zone heat presumably because the motorised valve is permanently open.

I'll need to dismantle the valve a little, just to see whether it is a broken spring, but what I'm not sure is how much dismantling can be done without water coming out unexpectedly! Any clues? Thanks.

[Graeme]

In message <wkC80XB$X$ [e-mail]>, Graeme [e-mail]> writes

Doh! Just looked on YouTube and answered by own question. I can see that releasing two screws enables the whole motor unit without releasing water.

Plan A is to do that, then do a straight swap with one of the others (we have four in total) which should prove whether or not it is just the motor unit or the internals of the valve itself.

[Dave Liquorice]

(From memory) remove screw holding cover on, remove cover revealing a couple of screws that hold the actuator onto the valve body. Remove those and the actuator can be pulled off the shaft of the valve without getting your feet wet. IIRC they aren't double insulated so there could be bare connections with mains on them.

[Alan]

Unless it is 20 years+ old, which does release water if you take the head off. If it has a flat top cover, then it is old, and will probably need a partial drain off, and complete new valve.

[Graeme]

Thanks Dave, exactly right. I had to do something similar a few years ago, but had completely forgotten the procedure.

[Andy Bennet]

Just take the cover off, undo 2 screws that connect head to valve body and it should pull away. To save faffing about - if a 2 port head - Strom do a replacement head that fits Honeywell valves for a lot cheaper than original. They are solidly built with all metal gears and I have not had one fail yet:-

[Graeme]

In message [e-mail]>, Andy Bennet [e-mail] writes

Thanks Andy, that looks perfect. Just to be clear, the unit supplied is exactly as illustrated, and not just the motor part? In other words, apart from the wiring, just cover off, two screws, job done?

Thanks!

[The Natural Philosopher]

That's how I have done honeywell 2 port heads in the past, yes Its the wiring that takes the time..

[Andy Bennet]

Yep its a complte replacement for the head - with the addition of a light to tell you when its activated!

[Graeme]

In message [e-mail]>, Andy Bennet [e-mail] writes

Perfect. Duly ordered - and thanks.

[Roger Mills]

There's a strong chance that your diagnosis is wrong. The lever is for manually opening the valve, and when the valve *is* open the lever will move freely back and forth.

It's quite possible that the wet part of the valve has stuck in the open position such that the return spring in the actuator isn't strong enough to close it. This will be apparent once you remove the actuator from the valve, because this will then whir back to the closed position, and you'll feel some resistance in the lever. Also, the shaft of the valve will be too stiff to rotate using your finger and thumb.

If the shaft moves freely and the actuator doesn't whir closed, the problem is with the actuator. Otherwise, it's with the valve. In most cases, you can free a stuck valve by working it backwards and forwards with a pair of pliers.

[Graeme]

In message [e-mail]>, Roger Mills [e-mail] writes

Thanks Roger. Almost certainly the actuator, as the shaft moves freely and has not closed in that water is still circulating beyond the valve (and heating radiators) even with the actuator completely removed.

[Dave Liquorice]

forwards

The valve needs the spring in the actuator to close. If you manually close the valve does the flow stop? Perhaps the ball has disintegrated. Does the actuator motor open and spring return when not on the valve?

[John Smith]

The easiest thing to do is just buy a new motorised head. You can get them cheapest on ebay. I bought a Honeywell with the valve body for about £30 as i thought it would be useful and indeed have replaced that too now. Be careful wiring in the new head as if the board is anything like ours it's rather small and easy to forget what goes where and to accidentally set another wire loose.

[Graeme]

In message [e-mail]>, Dave Liquorice [e-mail] writes

Having discovered the fault on Sunday, I put it all back together, awaiting a new head, and now it seems to be working perfectly. I can only think that I dislodged something, or eased a sticking part. Still awaiting the replacement head but, with three motorised valves here, it will come in handy one day.

[Graeme]

In message <2020101823510528942-nospam@nospamcom>, John Smith [e-mail] writes

I have taken multiple photos and drawn a wiring diagram, just in case :-)

What I'm not sure about is the two black wires which go into the valve, from the cable to the boiler. One black wire is connected to an orange wire, the other to a grey wire. Not sure whether it matters which black wire is connected to orange and which to grey.

[Andy Bennet]

The orange and grey leads go to a NC microswitch. The switch closes when the valve fully arrives at the open position. It does not matter which way round you wire those leads but i'm sure somewhere ther must be a convention. The blue and brown leads power the little motor and are turned on/off by your thermostat. (for completeness the yellow/green lead is the earth!)

[Andy Bennet]

I re-read the above just after I hit 'send'. Err the microswitch is NO not NC! soz

[John Smith]

It's well worth getting familar with the wiring so one understands what you are doing.

This is a typical S plan system with two 2-port valves like we have although we don't have a room stat only a cylinder stat and programmer.

Video also:

[Roger Mills]

Sounds like the valve was sticking and the actuator was ok - which is what I suspected.