Boiler does not turn on for hot water

QrizB

Congratulations on the successful investigation!

Qyburn

robshak said:

So does this mean a new valve head will resolve this mystery?

It's possible the valve isn't fully opening. It would be worth taking the head off and manually opening and closing the valve to make sure it's moving freely. Compare with the heating valve. With mine the travel between open and closed is only around 45 degrees.

Good result with the troubleshooting by the way. 

robshak said:

I also assume when the HW is called in the programmer and live feed gets to the valve, it opens then pushing the micro switch turning the boiler, like magic!!! 

That's it. Although the live from the programmer doesn't directly go to the boiler. Which means if the valve sticks fully open the heating (or HW) will run even when the programmer isn't telling it to.

Mister_G

The Honeywell heads are renown for failing.  It's either the motor (which is in a continuosly powered stalled condition) or the microswitches.  At least they are an easy replacement.

I've got through at least three in about 40 years.

Qyburn

By the way I've replaced microswitches on our valves, one was sticking On. Different make of valves though.

robshak

Mister_G said:

The Honeywell heads are renown for failing.  It's either the motor (which is in a continuosly powered stalled condition) or the microswitches.  At least they are an easy replacement.

I've got through at least three in about 40 years.

Do you think it is just a burnt motor because it doesn't open valve when hot water is called in the programmer? 

If so, will save me a lot not having to buy the whole head.

The microswitch is fine as when pressed with a screwdriver, it turns on the boiler.

FreeBear

robshak said: The microswitch is fine as when pressed with a screwdriver, it turns on the boiler.

If you can identify the make & model of the microswitch, it may be possible to source some new ones from ebay or similar. You may also find that there is a small amount of wriggle room that allows the switch to be adjusted slightly so that it switched on sooner.

Mister_G

robshak said:

Mister_G said:

The Honeywell heads are renown for failing.  It's either the motor (which is in a continuosly powered stalled condition) or the microswitches.  At least they are an easy replacement.

I've got through at least three in about 40 years.

Do you think it is just a burnt motor because it doesn't open valve when hot water is called in the programmer? 

If so, will save me a lot not having to buy the whole head.

The microswitch is fine as when pressed with a screwdriver, it turns on the boiler.

It could be either.  It may also be that the internal mechanical gearing is worn.  For the price of a replacement head (and the ease of replacing the whole thing) I'd go for a whole head.  The proper Honeywell one is about £60, but there are look alikes out there for half that.

I did replace a burnt out motor once, but I now just replace the whole head.  It's only held on with two screws.

One thing to check when the head is removed is that you can turn the shaft to its limits.  This may be preventing the motor turning it enough to activate the microswitch.  There are lots of videos on Youtube!

robshak

Hi all,

I would like to thank all of you for your valuable time and suggestions that helped me immensely to troubleshoot the issue I was having.

I can report now that the new motor has now resolved the issue.  The boiler turns on and heats water to send it to the HW tank as it should once HW is called in the programmer.  Took a long way to get there but finally here!

Thanks again and do keep up the good work you are doing! 

Regards, 

Rob

Mister_G

Thanks for coming back to let us know.

Out of interest, did you replace just the motor or the whole head?

robshak

Mister_G said:

Thanks for coming back to let us know.

Out of interest, did you replace just the motor or the whole head?

Just the motor..£14 total!! 😁