Motorised valve failure

[nky_84]

Hi,

Heating has stopped working and I believe it’s the motorised valve. Not sure on the life expectancy of these things but it’s less than 10years in this case.

I’ve had a look at it and the motor doesn’t kick in when powered and when I manually open the slider, the contact is a good 10mm away from the micro switch?!

I get that the motor might burn out but has it really failed that badly to bend all the mechanism or am I missing something here?!

Also, I’m planning on replacing the head only, is it worth replacing with expensive Honeywell (given it’s not even lasted 10years) or will the cheaper alternatives do / likely to break even quicker than that?

https://www.screwfix.com/p/honeywell-home-40003916...


Thanks,
Nick

[Danns]

Have a check to see what a whole new valve + head costs, I've found for Danfoss HP22's its cheaper to buy the whole lot, and use only the head.

10 years is a good run, I'd perhaps keep another in stock for when the other valves invariably fail. 3 of mine at 10 years failed within 6 months of each other.

Without knowing that particular valve well, cant comment on the microswitch / lever interaction coming up short.

Edited by Danns on Thursday 9th November 10:36

[B'stard Child]

If it’s a three port mid position valve the manual over ride gives you HW and CH together not CH only so it won’t make the microswitch

[tux850]

nky_84 said:

I’ve had a look at it and the motor doesn’t kick in when powered and when I manually open the slider, the contact is a good 10mm away from the micro switch?!

I get that the motor might burn out but has it really failed that badly to bend all the mechanism or am I missing something here?!

Many motorised valves (older Honeywells in particular) don't activate the microswitch when the lever is manually moved so don't read too much into what you've observed. With such valves the manual lever exists purely to aid draindown and filling.

Given the symptoms you have described I would recommend just replacing the motor, ideally from a recognised brand as unbranded motors often don't have good longevity. If you wanted to rule out a rare double-fault try latching the lever open and manually activating the microswitch to ensure the boiler and pump fire up as expected. Obviously be careful poking around live conductors inside the valve.

Edited by tux850 on Thursday 9th November 10:59

[nky_84]

B'stard Child said:

If it’s a three port mid position valve the manual over ride gives you HW and CH together not CH only so it won’t make the microswitch

It’s a 2 way

[nky_84]

Danns said:

Have a check to see what a whole new valve + head costs, I've found for Danfoss HP22's its cheaper to buy the whole lot, and use only the head.

10 years is a good run, I'd perhaps keep another in stock for when the other valves invariably fail. 3 of mine at 10 years failed within 6 months of each other.

Without knowing that particular valve well, cant comment on the microswitch / lever interaction coming up short.

Edited by Danns on Thursday 9th November 10:36

Thanks, good tip. I think I might try to replace the motor only as that’s even cheaper option 🙂

[nky_84]

tux850 said:

Many motorised valves (older Honeywells in particular) don't activate the microswitch when the lever is manually moved so don't read too much into what you've observed. With such valves the manual lever exists purely to aid draindown and filling.

I would recommend just replacing the motor, ideally from a recognised brand as unbranded motors often don't have good longevity.

Edited by tux850 on Thursday 9th November 10:56

Good to know! It did have me puzzled somewhat! Will try a motor replacement and see how I get on. Thanks!

[Harpoon]

We've had to replace the motor head on the 2-way valve the hot water side of our heating twice - we've lived here almost 8 years.

[phumy]

If and when you do just change the motor, when you have the motor off check that the valve is not stuck, you can turn it with pliers on the shaft. Sometimes they can stick quite hard, you put a new motor on and that will burn out too. Possibly the reason the motor may have gone in the first place

[jonwm]

My heating one failed after 2.5 years (new build)

[tux850]

phumy said:

If and when you do just change the motor, when you have the motor off check that the valve is not stuck, you can turn it with pliers on the shaft. Sometimes they can stick quite hard, you put a new motor on and that will burn out too. Possibly the reason the motor may have gone in the first place

A stuck valve won't actually cause the motor to fail*. They are designed to sit quite happily in a stalled state - indeed that is what happens every time they operate because there is nothing that cuts the power to the windings once the valve is fully open.

(*Edit: Fail as in burn out. Obviously it will prevent proper operation)

Edited by tux850 on Thursday 9th November 15:28

[B'stard Child]

nky_84 said:

B'stard Child said:

If it’s a three port mid position valve the manual over ride gives you HW and CH together not CH only so it won’t make the microswitch

It’s a 2 way[/]

OK

[Abdul Abulbul Amir]

I replaced my 3 port similar Honeywell motor a couple of weeks ago....bought from screwfix but they are twice the price of the 2 ports. Mine lasted as least 16 years so not bad.

Easy to replace but make sure fully electrically isolated before taking the cover off to remove and rewire.

Definitely give the expose valve spindle a covering with wd40 and use pliers to activate and then apply more wd40. I may make it an annual or biannual activity to do this along with a system drain down and refresh.

[nky_84]

Replaced the motor and back up and running.fraction of the cost of full unit/ valve and no drain down:-)

Thanks all!

[southerndriver]

Too late now, but a few years ago my Honeywell motorised valve failed. I took the head out and found a problem with the microswitch which I replaced with one from Maplin (a chain now gone, unfortunately). I later found that the microswitch could be dismantled easily and just cleaning it out restored it to operation.

[tux850]

nky_84 said:

Replaced the motor and back up and running.fraction of the cost of full unit/ valve and no drain down:-)

Thanks all!

Nice one!

[defblade]

I've found mostly either the microswitch fails, or the thin plastic bits that hold it in place. I've got a small bag of microswitches in the garage, but now I reinforce the mounts from new and (touch wood) no problems since. Except having to get the adjustable wrench on the valve spindle every now and then, as said above.

[ooid]

thread revival.

My home boiler heating has this valve (honeywell motorized zone valve) and we replaced it already in february as it was stuck, not working. Yesterday it stopped again, and we changed it again. The service guy said, it might be in relation to the cold ? (The boiler set up is in the attic, it is not fully insulated so could out there!). Could that be the reason ? It seems quite strange having such a short life.

[Byker28i]

ooid said:

thread revival.

My home boiler heating has this valve (honeywell motorized zone valve) and we replaced it already in february as it was stuck, not working. Yesterday it stopped again, and we changed it again. The service guy said, it might be in relation to the cold ? (The boiler set up is in the attic, it is not fully insulated so could out there!). Could that be the reason ? It seems quite strange having such a short life.

Is the valve fully free or sticking? Take the solonoid off and work the valve with a spanner/adjustable ensuring it's free.

Our's go about every 5-6 years, they don't seem to last. So much so I now have a separate connector box wired in for easy replacement, it's only 5 wires

[GasEngineer]

ooid said:

thread revival.

My home boiler heating has this valve (honeywell motorized zone valve) and we replaced it already in february as it was stuck, not working. Yesterday it stopped again, and we changed it again. The service guy said, it might be in relation to the cold ? (The boiler set up is in the attic, it is not fully insulated so could out there!). Could that be the reason ? It seems quite strange having such a short life.

Sounds like a faulty actuator. Replaced in February it will still be under warranty.

I've known them fail from being too hot - eg in a very enclosed space - but not know one fail due to cold.