How to Repair a Motorised Central Heating Valve 

Thanks for this. In early December 23 when servicing our heating the engineer told us the zone valve was sticking and needed to be replaced because there was a 10 minute delay before system fired up. He had ordered the part and would come and fit it. In February the valve started sticking in the open position and after watching this video I was able to release it and messaged the heating engineer to have the work done. No response. Eventually as the problem got worse I ordered a Synchron Motor for £13.95. It arrived in a couple of days and was fitted in about 20 minutes. The hardest part was re fitting the tiny screws. All working great now. Thanks for providing so many really helpful instruction videos. They are a great help.

Spot diagnosis. I just needed to manually move the lever on the heating circuit back and forth a couple of times, and now it works fine - might have been a build up of material in the valve itself preventing operation. So you could try that before replacing any parts. Thanks Roger, saved a few quid there!

Yay, thanks so much - just sorted out our valve issue £14 for the part. I’m glad now that the plumber wasn’t able to come out as it would have cost much more than £14 I’m sure. Also feels good to do it myself.

Thanks for this excellent video. My daughter was quoted £330 by CH company to replace the motorised valve and that’s on top of a call out fee of £86. After looking at your video I sourced a syncron motor for £9.75 and fitted it myself in 20 minutes. A tremendous saving. My daughter is very pleased. Shame on the CH company. Thanks once again. MG, Wirral.

This is such a good video. It’s so clear and concise. After 5 visits from plumbers who failed to diagnose or fix the problem we ordered the part and did the job ourselves. You are the only person who helped us and we must have saved a fortune. Thanks

Yes plumbers will inflate the job. One was vague about the ''valve'' then immediately said it maybe mechanical in which case he'd have to drain the system, bleed all the radiators etc.. and it would be £180 + VAT labour, and the part. Probably charge for the whole unit which is just shy of £100. Total cost nearly £400. No wonder people despise plumbers and other tradespeople, for their sharp practises.

Fantastic video. Really clear and concise. Good context and then deep dive. Helped sort my hot water issue out in 15mins and £15 rather than the £140 for a plumbers labour as quoted. Maybe a few ideas for some more: - changing/recharging an expansion vessel - draining a hot water cylinder. - swapping out a pressure relief valve. Overall well done and thanks!

Excellent, love this guy. right on and uncomplicated, top work dude!

Thanks a bunch for this, I waited for three different plunbers/heating engineers to arrive and would have been happy to pay whatever, but all no shows. so on Sunday I swapped the downstairs valve ( faulty) with the hot water valve and just used the electric to heat the water. today I bought a new valve and replaced the water heating. all good now, thanks again.

Nice video Roger, sparks tend to avoid central heating wiring as it goes against most things they are taught! A lot of people shy away from it but it's fairly simple at the end of the day, it's just individual circuits that turn things on or off, the boiler is dumb it just knows when to fire up.

Really useful explanation about motorized valves. It helped me to fix my central heating problem. Thanks Roger.

5 minutes in and I’ve fixed my heating by opening that valve. Boom subscribed. Excellent explanation. Thank you

This is a "public service" you giving here! 👍 Thanks

Thank you very much. I managed to fix my CH myself after watching this video. It took 20 minutes cos I was being careful and only cost £15. Top man.

Thank you. My motor was just spinning non-stop and getting hot. I removed it and noticed no resistance when turning the screw arbor. New Synchronised Motor ordered from Screwfix - all back up and running now :-)

Hi I don’t ever comment on videos but after watching yours I managed to completely fix my central heating that we have been putting up with not working properly all winter. I just wanted to say thank you very much for posting such a helpful and clear video. It turned out to be a very easy job! Thanks for you help!

Hi great vid, I am having a hot water problem think it's this valve but want to know. Will this faulty motor cause the boiler to not receive a signal to start?

great help, well explained and easy to implement. we had the motor making a noise, we were not sure what it was, so called the assistance (for which we pay insurance). they would not even come, and if they did they would have charged 50£, despite the insurance said it was covered. 20£ of part, 30 min of work on my side, and the job was done. thank you so much

just did this on my boiler, cost £24 for the motor from screwfix plus £4 for some grease to daub on the cog. The only awkward bit was getting to the screw! Thanks for the video :)

Unless it's a really old Honeywell valve, you can change the head without draining down. Also the boiler will not fire up just by locking the leaver open. The manual operation is for filling and draining the system. If the lever is locked over, the boiler will operate if the other valve is calling for heat or hot water.

Hi all, How do you ensure that little cog-drive of the new motor is in the correct position to match the position of the gears driving the valve mechanism as you mate the new motor onto it's base plate. To elaborate. The new motor is in 'divert to CH position ' but the actual valve and its gearing is in the 'divert to HW' position. When the new motor is fitted how do you ensure that the two mechanisms are pointing the same direction. TIA Well, to answer my own question above, I popped into the local plumbers merchants to by the new motor and spoke to a plumber and the shop assistant about my question above. Both of them agreed that they'd never thought about the problem and to just throw the new motor on. Which I did and it works!!!! £9. Thanks Skills Builder.

watching this in 2024. really helpful to understand how the motor can be repaired. thank you

A very informative video, I suspect this is the fault that’s causing her radiators to heat up when CH switched off. I can now change the motor after ensuring the 3 way valve isn’t jammed . Hopefully it will work, if not I’ll proceed to draining the system and fitting a new valve body and actuator Many Thanks, hopefully it will save her a plumbers call out and labour charge which as a retiree she simply can’t afford

I have a buzzing coming from my CH diverter valve. Quite loud especially at night. This is when the system is off. Is there something wrong as I am sure it was never this loud. Some nights it's quiet. No problems with HW or CH so far. Is it on its way out? Just switched on HW, valve whirred in to action, buzzing gone. Switched off HW within a minute and the valve is dead silent. No humming or buzzing! Peace and quiet. I wonder if it is drawing current when buzzing. The electricity bill was a little high last month. Not using anymore appliances than we usually do.

It is rare that the motor actually "burns out" or fails, rather, the brass drive gear on the motor gets stripped and then makes insufficient contact with the adjoining gear that opens and closes the water valve. You might even hear a clicking sound as the motor partially engages the adjoining gear and then slips as it meets the stripped portion of the drive gear on the motor. Honeywell used to use a better alloy that did not strip but the newer version better helps their bottom line.

I just replaced mine (which is 24V). The failure mode was that the valve was stuck partially open. When the motor is powered up, it will spin and open the valve, until it's open. What's interesting is that the motor stays on, constantly trying to turn and holding the valve open. When the power turns off, it stops trying to open and the spring closes the valve. The motor is designed to handle this, but it is also the reason why you can only have limited number of motors connected to one transformer (in my case, it is 3 on one transformer, and 2 on another). Mine failed with the gears getting stuck open (it was 45 years old). As I started to remove the motor, I heard the insulation on the wires cracking right where they entered the motor and the wires were now bare. Why didn't I just change the powerhead like most plumbers would? Because my powerhead was attached with all 4 screws, not just 2, and removing it would have required draining the valve sections. Thanks for showing us how to change out just the motor!

6 am and my wife screams that theres no hot water. Emersion on. Lever moved. I'll pop out later to pick up a new valve. Happier wife... Every man should know this stuff for a peaceful life!

The road to hell is littered with people who switched the circuit off. Those who tested for dead ( no energy present) are not along that road. Always test for dead. Always. Always do it with a dedicated tester, NOT a multimeter or wand. I've seen a sparkie get a belt from a " switched off" circuit. He forgot about the anti-condensation circuit in the JB. Boom! Takes 5 seconds to test.

retired plumber, aggree with all. Very helpful and not beyond your average DIY person.

I think my motorised valve has burnt out. Got no heating. The valve feels hot and makes a buzzing noise when I pull it to the manual position. And the boiler isn't igniting nor coming on. My usual plumber's phone is dead. Is the motorised valve connected to the boiler ignition. I have a 23 year old Potterton boiler. If it's a simple job of replacing the motor I may attempt it. But if it's a bigger job I may have to get a plumber in.

What kind of wankers gave 53 dislikes, This mans a genius

Some aftermarket synchronous motors only last 2 or 3 months ! Others are better but luck of the draw. Honeywell zone valves in general have dropped off a cliff in terms of reliability but still cost the earth…….swap them out for Drayton these days 👍

Bloody hell. Plumber charged me £180 for this little job. Won't fall for that again!

Thanks mate. Mine had stuck!

Hi Roger. Can you please help me? I have had to replace this valve for my central heating 3 times in 5 years. What could be the issue here? It appears to work then sometimes it ether won't close or won't open automatically. I would really appreciate your help. Thank you.

thanks a lot. now we have (rain)water in the toilets again!

brilliant video. my unvented cylinder was not heating water although the boiler was working. what you described is exactly what my valve looks like. a £10 part next day from amazon sorted it! cheers i reckon a plumber would have been lookin at over £100 to sort that

Two zone heating system but one zone occasionally nit running when both heating programs run together. The affected zone's motorised valve's on light wasn't lit but the other was. Given there's no light on the motorised valve would this be more likely the EPH control unit? Being intermittent is hard to tshoot on. If I run an hour boost the heating then works.

I have a zone valve passing water when it should be closed. I bought a new valve set and first tried changing just the actuator. I tried that for a couple of weeks but it was still passing water. So I replaced the valve fully, so new valve and the new actuator. It is still passing water. When the zone call for heat is on the motor starts and opens the valve and the boiler activates as it should. When I turn it off the spring closes the valve and the boiler shuts off. I can see that the actuator mechanism has moved back to about where it should be for closed. But if I turn on another zone then water still passes through the faulty one. Even with a brand new valve. I have double checked that the flow direction as labelled on the valve is correct with regards to the flow outlet from the boiler, plus it's the same as all the others anyway. I don't understand what's wrong. Is my new valve faulty too? Do I need to return it and buy a different one? The only difference with the other zone valves that work fine is that they are mounted vertically and the faulty one is horizontal. That shouldn't be a problem should it?

I know the 3 regular wires of five. Orange and Grey are the micro switch wires. Grey is the permanent live which operates the switch to the Orange that sends the signal to the pump and boiler to fire up

Haha My recent experience exactly, Plumber says get electrician and vs vs. Thanks Great help that.

Excellent comprehensive video and a real money saver. Many thanks. Pay extra special attention to isolating the electrical power supply..as Roger says!

Yeah, easy to replace if your plumber didn't place 22mm pipes an inch in front of the valve cover so you can't get a screwdriver in there!

Thanks for another excellent video. I wish RU-vid had existed when I had to change motorised valves for the first time 20 years ago. I was quoted circa 200 pounds back in the 90's for a new motor by a plumber and had to work it out myself-as you say, its not a very difficult job and in my case the motors have failed every few years (mainly after the summer, when the motor hasn't been exercised). It might be worth mentioning that the CH programmer should be set to run for a few minutes, even in the summer just to exercise the motor.

as a girly who had this issue twice in the last few years I wanted to grasp my understanding of why it's failing, plus it shall help me to query if the plumber can just attempt motor repair

If the motorised valve fails, surely the boiler won;t fire as the microswitch won't be activated?

Great video thanks Roger so well explained and brilliant close ups which always helps ! :o)

If you have a '3 way' valve, it is sometimes the microswitch that goes and not the motor. You can get the complete unit (the silver box) and swap it with just two screws. Again, no draining required. You have to trace the cable back to the junction box, where there are usually five wires. The colour code seems universal. Swap the wires one at a time and you should not get into trouble. Power off of course!

The valve running hot turned everything off from the power Next morning return the power to the central heating system And thevalve started to warm up with no hot water running through it?Take it That the valve is faulty

I am guessing the negatives are from Plumbers who are not going to get to rip you off.

Brilliant video thank you, can you tell me how to isolate the power supply to the head without having to turn the power off to the entire house please ? Thanks.

Reason why I like to change the whole valve is so theres no come backs on the job.

play play fellow master plumber ,greetings from dublin

My hot water has gone this week and I can't get the switch on the motorised valve to get past the lug and lock in. Its as if something is blocking it. It also doesn't spring back when I let go, it just stays where it is.. Any ideas what the problem could be there?

Great video, clear information and very helpful

hi Roger - just found yer site - excellent stuff - cheers dave moylena plumbing and heating

Thanks mate sorted the heating out great vid. Cheers !!

Mine started banging earlier today - very frightening. Trying to diagnose before getting ripped off.

thanks Rodger. will be replacing my motor soon.

well done superb instruction, found this very very easy with your help

Brilliant tutorial. Very clear. Thank you so much.

I had this exact same problem with my central heating.... no hot water, after watching this I checked that small lever and yes it was loose with no tension on it. £10.50 later with a new motor off ebay fitted glorious hot water again. Thank you so much for such a clear and easy video to follow with good clear instructions. A subscribe well worth having.

Thanks for the video save me 300 British pound that I was quoted by a company to change the valve and I just bought the motor for 19.99 and fitted myself in 10 min and now we have heating in the house

Thank you. Very interesting. I have just replaced the last 4 of 4 zone controls in a 20-year-old home.

Best breakdown ever, zone valve fault! :) I haven't got DHW but my heating is working lol

saved me a small fortune, thank you.

Excellent video. It was very helpful. With your great guidance, I replaced the faulty zone valve and I now have hot water. Thanks

Splendid advice very well presented thankyou

Excellent instructional video. Very clear, accurate and comprehensive. Replaced motor in ½ hr for £13.

great vid.. my plumber (unfortunately now retired) said I would be able to do this myself.. scared stiff because I thought you needed to turn the water off! ...

Good videos as ever but unfortunately the plumbing world have never moved on with its thinking. When you are installing this type of system install two pumps and two non return valves. One for the hot water and one for heating. A change over relay on the boiler controlled by the two thermostats and job done. I have installed many systems with this configuration and it works perfectly. One other little piece of information that most if not all plumbers don't know is why before pressurised systems we had loft water storage. The answer goes back to our friend Napoleon who threatened to poison our water supplies, village ponds in the 19th century. This was because us Brits were sending infected prostitutes to France to infect his soldiers. Nice one. ,

My boiler is a Vaillant ecoTEC plus system boiler. Heating works while hot water not. I followed what you said to manually open the hot water valve. The boiler does not start.

Thank you, all sorted. Managed to drop the crimp into a really awkward place but fished it out with a Knitting needle! 😂😂😂 Still alive so all’s good! Just need to work out why half of my house isn’t heating? Was like this before I changed the valve 😂

Thank you Roger, simple steps to help a layman like myself to understand. I fixed my daughters central heating problem at the weekend which not only saved them ££’s but it also saved them having a cold weekend.

Thanks Roger - this video explained the problem and solution very clearly - I replaced my two motorised valves and fixed my heating problem.

Can anybody help? 1. My systems boiler fires up even when the programmer is in the off position. 2. The pressurised cylinder that I had fitted does not have a pressure gauge - I am assuming this is quite wrong. 3. What would you expect to be charged to replace a small expansion vessel. 4. The expansion vessel makes a huge 'groan' when hot water is first drawn. All comments greatly appreciated. (chrishodges@btinternet.com)

Brilliant explanation. Many thanks.

Can the reverse happen and these valves stop working but the pipes are open!

Roger, THANK YOU so much! 1am the night before a bank holiday, staying at my mum's, and I notice after watching the snooker that there are noises coming from her airing cupboard - the pump is running hell for leather despite both CH or DHW being off. Boiler on, of course, and her smart meter energy monitoring gadget screaming blue murder! I checked her Hive system, and eventually decided that the problem might be one of the S-plan valves sticking open. I've dealt with combi systems before but never something like this. Your video gave me the confidence to diagnose the issue - sure enough, the lever was loose on the DHW valve. So I popped down to Screwfix in the morning and fitted a new valve head unit. It's all working nicely now. The old unit really isn't in great shape (hence replacing the whole head) but I'll probably run my multimeter over the motor sometime. I'll definitely be checking out a few more of your videos. Thanks again, and keep up the good work!

hi Roger, my hollywell valve seems to be vibrating after the heating (radiators)/hot water has been on for an hour or so. In order for me to stop the vibrating i need to turn the hot water on for 5 secs or so, then off again. This for some reason stops the vibration. Do i need to simply replace the valve? Cheers Roger

Hi roger thanks for the informative video and looking to replace the synchron motor on my Honeywell 2 port valve 40003916-001 and I am tempted by the cheaper generic motors over the replacement Honeywell product, which you will know is a lot more expensive, what’s your view on this and any recommendations? Thanks again regards simon

Just to reiterate the good comments stated already, great video!!! and cheers. This video was just the info I needed to get past my initial problem, which is turn tells me exactly what the issues was. Thanks for the clear delivery, I have subscribed. Great site.

Brilliant video. Thank you!

Brilliant instructive video. Very well and explained...

My actual valve is stuck. What is the process to replace the pipe section? Does the system need to be drained? The one that is faulty is for the hot water. The valve is stuck open and therefore boiler running constantly.

Really clear & informative video. Turned a daunting job into an easy one took the motor off, found the gog was gunged up. Greased the cog and now works fine cost £0, so thank you for saving me £300 or more!

Good advice Roger. The motors are only about £15, so you can save a bomb by doing it yourself.

A massive thank you for this video. I have had no Hot Water but Central Heating is working perfectly. I was just about to call in a plumber with all the cost that brings when I saw your excellent video. I did the diagnostic test on the valves and one did seem to be faulty. To be extra sure I removed the motor from the CH valve and put it into the hot water valve. Tested the hot water and it worked perfectly. I have now ordered a new motor for little more than a tenner and will fit that back into the CH valve. I reckon I probably saved £200 or so, I also have a great sense of satisfaction and the wife thinks I'm brilliant! Thanks again Roger!

I am getting a problem where the syncron motor fails every few months. It is on a yplan system and the fault is no heating (the boiler is not called (orange wire does not come live)) I have even replaced the complete valve on more than one occation but still have the problem of failing motors. Upon stripping the motor down I see there is one cog on the gear train, made of plastic, and it alway this cog that has stripped a few teeth. (I guess this plastic cog is acting as a machanical fuse). I am chacking for air locks and seem to have none. any ideas?

Heard a horror story from a customer. Someone charged £1500 to change two motorised valves and a pump. They changed the heads (electrical part) and a cheap pump from screwfix. Depending on age of the system changing motors great.

Great info, Thank You. I had issues last evening with the boiler not firing up when Hot Water was called for. To confirm it was the Valve, i swapped the two control wires over, swapped the Hot Water and Central heating valves over, then called for Hot water and the boiler fired up. I then called for central Heating and sods law, that fired up also. Chances are the motor is on its way out so ordered one today.

Hi I have a buzzing noise from the Honeywell motorised valve. Please can you help. How do i know for sure if it's just the electric part or the actual valve? Or is it best to just replace the full item?

I have a 3 zone system (upstairs and downstairs heating and water cylinder). I am getting heat in all 3 zones wherever I turn on any of the zones. I'm thinking the zone valves are passing but is there anything else it could be before I replace all 3 valves?

excellent....mine is supplying hot water to the central heating when its not in demand....could this be the same problem?

Roger or if anyone can help . I have had two 2 motors fail on me in the past three years on the same circuit. The first one installed July 2021 failed in Nov 23 was replaced late Nov last year and the same valve has failed last week Sept 2024 10 months after it was fitted . Is this coincidence or are there any possible issues with the system Its a Zone valve that operates my UFH and does get used a lot . But surely these should last 10 yrs at least Thanks in advance .

Thanks I actually have one of these that's failed. Going to give it a try as a DIY project, you probably saved me a service call.

This video helped saved me £££‘S Woke up last night about 2am feeling really hot and sickly think what’s going on, wife wakes also feeling the same then we realise our bedroom radiator is on full! Doesn’t have the thermostat vales because there is a thermostat walled mount in the room. I check the thermostat on the wall and see it’s not on however reporting that the room temp is 28c! So off the airing cupboard and yep the combi broiler is churning away running the upstairs central heating. My central heating is zoned so upstairs heading is separate to down stairs and two thermostats Controls these one in our room upstairs and one downstairs near front door. Check down stairs and it’s all cool so then I troubleshoot and find my way to where the two valves are that control both zone and sure enough by going near the upstairs one can feel the heat so not I’m sure I’ve found where the issue is caused next is good old google at 2:30am to see what sort of fix and the damage to the wallet. Search returned this video so this morning been to screw fox picked up the motor swapped it out form the old and all is working well again! I had the opposite issue where the valve was stuck open so the boiler was feeding heat but still the same fix. Now subscribing to this channel thank you again From a very ashamed to say novice diyer!

Great video, many thanks.

Can you put it on manual settings it automatic is not opening the valve

Thank you, I found 2 of my 5 motors not working and had no hot water pressure, can't imagine how much a plummer would charge me