Hot water system stopped working.

[Deleted member 267285]

That should show me if the MV for the HW is working correctly or not Y/N ?

No. If it’s working correctly, then I doubt we’d be here discussing it. The only way to test it properly, would be electrically, using a multimeter. If when you select the heating to fire the boiler up tomorrow, manually latch open the valve and water heats the cylinder this would tell me something inside the actuator has failed (motor or microswitch). If you’re capable of replacing one, without the need for draining down then you can fix this yourself.

 

[dilalio]

Ah, now I understand ( I think ! ) Thank you. Have had our showers now and have switched the immersion off. Tomorrow morning I will open the MV for the HW manually and then press Extra hour on both the heating system and on the HW system. That should show me if the MV for the HW is working correctly or not Y/N ?

What @ianmcd is trying to convey to you is...

The MICROSWITCH on the HW zone valve has failed, which means that putting hot water on will motor that valve open BUT the microswitch is not MAKING the connection and thus sending 240v to the boiler/pump via the ORANGE wire, to fire boiler/run pump.
By running one/both the heating zones, the boiler gets power to fire via them and will send heated water to the cylinder IF you have manually latched the HW zone valve to open!

Hope that explains it for you

 

[scooby1]

No. If it’s working correctly, then I doubt we’d be here discussing it. The only way to test it properly, would be electrically, using a multimeter. If when you select the heating to fire the boiler up tomorrow, manually latch open the valve and water heats the cylinder this would tell me something inside the actuator has failed (motor or microswitch). If you’re capable of replacing one, without the need for draining down then you can fix this yourself.

Yes, that is what I intend to do tomorrow morning. If that doesn't point to the MV being caput then it's time for the heating boys I think. If I can get the HW to work then I'll investigate the MV and see if it takes apart alright. I seem to remember that last time I changed a MV I just took the box off it and replaced the innards.

 

[scooby1]

What @ianmcd is trying to convey to you is...

The MICROSWITCH on the HW zone valve has failed, which means that putting hot water on will motor that valve open BUT the microswitch is not MAKING the connection and thus sending 240v to the boiler/pump via the ORANGE wire, to fire boiler/run pump.
By running one/both the heating zones, the boiler gets power to fire via them and will send heated water to the cylinder IF you have manually latched the HW zone valve to open!

Hope that explains it for you

Yes, got that now. The Honeywell MVs on the system are 9-10 years old. Can the innards still be purchased ? I am having difficulty seeing a number on the box that covers them. It's all dark in there now and I will have to have a decent look tomorrow morning. Are all MVs serviceable like this ?

 

[ianmcd]

It might just be a failed Synchon motor , if it is they are not expensive and can be changed without draining down

 

[Deleted member 267285]

Are all MVs serviceable like this ?

Most of them.

 

[scooby1]

Sorry but after thinking about it I am still bewildered. If, as you both say, the HW won't kick in until the heating does then how does the system cope when the heating is turned off, say in a very hot period in the Summer ? The HW still comes on in those conditions.

 

[Deleted member 267285]

Sorry but after thinking about it I am still bewildered. If, as you both say, the HW won't kick in until the heating does then how does the system cope when the heating is turned off, say in a very hot period in the Summer ? The HW still comes on in those conditions.

We’re saying this because your valve has failed, if it was working correctly then it would work on its own in the summer, and any other season

 

[scooby1]

I am getting the impression that you are quietly confident that the problem is that the valve has failed in which case, if I can find the correct innards for the valve I can fix it myself. Are Honeywell MVs all the same inside or do I need to take the cover off first to get a number ?

 

[Deleted member 267285]

V4043 is the complete valve, but you just need the powerhead really, or 230vac synchron motor (if this is the fault).

 

[scooby1]

V4043 is the complete valve, but you just need the powerhead really, or 230vac synchron motor

Have just watched a helpful video on YouTube. Are Honeywell synchron motors all the same or do I need to take the cover off and find a number ?

 

[Jajodu]

Have just watched a helpful video on YouTube. Are Honeywell synchron motors all the same or do I need to take the cover off and find a number ?

I can't believe all three zone valves have failed. Time to get the multimeter out and measure whatsw happening.

 

[scooby1]

I can't believe all three zone valves have failed. Time to get the multimeter out and measure whatsw happening.

They haven't all failed. The CH is working as it should. It's just the HW that isn't working and the more I think about it the more I think that it's the MV that is at fault.

 

[Jajodu]

They haven't all failed. The CH is working as it should. It's just the HW that isn't working and the more I think about it the more I think that it's the MV that is at fault.

Sorry, misread your original post.

 

[Deleted member 267285]

Are Honeywell synchron motors all the same or do I need to take the cover off and find a number ?

Genuine Honeywell I believe have the word Syncron written on them and cheaper ones have Syncronous. Price is a clue, but they do the same thing, but 1 should last longer than the other.