Odd problem with heating/boiler. One-off or something on the way out?

[Mottie]

Odd problem, as above. Just got home from a weeks break. We have a sealed 'S' plan central heating system and unvented hot water. Vaillant ecotec boiler, Honeywell digital room stat, controller and motorised valves. When I went away I turned the hot water off at the controller and left the heating on the timed system but turned the room stat down to 10° in case we had a cold snap. Came in, turned the room stat up to 23° and put the hot water back on constant. Both lights on on the controller were on but the pump light didn’t light up or start pumping so nothing happened. Turned the power to the system off and heard the whirring sound you get when one of the motorised valves moves, gave it 10 seconds, switched the power back on. Both controller lights came on immediately, the pump light came on and started pumping and the boiler fired up. Everything is working fine now. Could this just be a one-off or is it a sign that something is on the way out?

 

[durhamplumber]

Could be a one off.Part that goes wrong most frequently are motorised valves,the top part.Sometimes they just stick a bit.

 

[Mottie]

Odd problem, as above. Just got home from a weeks break. We have a sealed 'S' plan central heating system and unvented hot water. Vaillant ecotec boiler, Honeywell digital room stat, controller and motorised valves. When I went away I turned the hot water off at the controller and left the heating on the timed system but turned the room stat down to 10° in case we had a cold snap. Came in, turned the room stat up to 23° and put the hot water back on constant. Both lights on on the controller were on but the pump light didn’t light up or start pumping so nothing happened. Turned the power to the system off and heard the whirring sound you get when one of the motorised valves moves, gave it 10 seconds, switched the power back on. Both controller lights came on immediately, the pump light came on and started pumping and the boiler fired up. Everything is working fine now. Could this just be a one-off or is it a sign that something is on the way out?

Update:
Exactly two years to the day, we've come back from a weeks holiday to have the same problem! This time I have Hive fitted so different controller and room stat. I suspected it wasn't working again as when we left the Peak District, the house temperature was 15.3° (I had set it to 22°) and when we got home it was still 15.3° and the system wasn't on despite all the controls being switched on. Switched the power off to the system, waited 10 seconds, switched power back on and up it started. House is just starting to warm up now. What could it be boiler or valve motor contacts? Is it worth changing the motor head on the 2 port heating valve?

 

[Deleted member 267285]

If everything is calling for heat, when asked, I would say more likely the 2 port. Turning all off would kill the permanent live to the 2 port, so would spring return.

 

[Gasguru]

Weak motor in the zone valve...

 

[Mottie]

If everything is calling for heat, when asked, I would say more likely the 2 port. Turning all off would kill the permanent live to the 2 port, so would spring return.

Weak motor in the zone valve...

So, this is my valve. (All working fine now by the way).


Obviously I'll use genuine Honeywell parts but shall I change the whole head and wiring loom where it goes into a junction box or just the little motor with 2 wires inside the head?

 

[Gasguru]

With the power off pull the motor out (connect a temporary earth bond wire..I use croc clips etc), power on and create a heating/hot water demand.
With a good motor it should be a struggle to stop the cog turning with your fingers.
Only ever use the genuine motors (available badged as Draytons from screwfix)...the knock-offs are a waste of time.

 

[MeldrewsMate]

Have you considered changing your holiday dates?

If you know how to remove the valve head then exercise the valve shaft with a small spanner. It should be easy to move across its 90 degrees or so. If it's stiff at first, but then loosens after a few wiggles you can fairly assume that is/was the cause of your failure. After a week of sitting in one place doing nothing (that's the valve, not you) it may have refused to open fully.

If you do no repairs, and the same happens again in two years, try also turning on the hot water from the Hive App...if that valve has even cracked open you should see a marginal increase in room temperature as the hot water demand causes the boiler to fire.

 

[Gasguru]

90 degrees..sure on a Danfos or Sunvic shoe valve but Honeywell ball valves the movement is around 20 degrees.

 

[Mottie]

Thread resurrection.

Same again after returning home after a few days away. I must admit I didn’t get round to doing anything about it last time as it worked after switching the power to the heating off and back on and I just forgot about it. Got home thus time, turned the heating and water on - nothing. Pump didn’t start and boiler didn't fire up. Switched off power to heating, heard a motor whirring/returning under spring pressure(?), switched on and it all fired up.

I've had this problem with two different boilers and two different programmers so it can’t be them that’s causing it. What’s puzzling me is that if it was the motor on the valve for the heating, why didn’t it all start up when I turned the hot water on as that’s a separate valve and motor?

Like cars, it’ll just keep on working now until we next go away so any tests now won’t show up anything, will it?

 

[Deleted member 267285]

Motorised valve failure, its not the programmer or boiler. Basically the microswitch isn’t making inside.

 

[gas112]

Motorised valve failure, its not the programmer or boiler. Basically the microswitch isn’t making inside.

yep sounds like the arm isnt hitting the microswitch everytime

 

[Mottie]

Motorised valve failure, its not the programmer or boiler. Basically the microswitch isn’t making inside.

yep sounds like the arm isnt hitting the microswitch everytime

On the heating, the hot water or both? Shouldn’t the hot water have kicked in when switched on?

 

[Deleted member 267285]

Sounds like both if neither valve are bringing the boiler on.

 

[Mottie]

I think I’ll wait until the summer when the heating is not used, drain the system down and just replace both valves complete with heads etc.