Help me diagnose my CH issues?

[SomebodyElseDoIt]

I had the heating on continuously on Christmas day. When everyone had gone, I switched the programmer back to its normal 'twice' setting, but the heating continued to run. I then tried all the programmer settings and it continued to run on all settings, including 'off'. Also, it would not shut down even when the room thermostat was set to minimum. In order to avoid roasting overnight, I switched off the electricity supply.

In the morning I switched the electricity to the boiler back on, and it was exactly the same. We were out for most of the day, so I turned the heating control knob on the boiler to 0 (and left the electricity supply on). The boiler/CH did not run.

When we got back home I turned the knob on the boiler back to its normal '3' position. However, the CH did not run. On fiddling with the programmer, the boiler would fire, and the pump would run, when the hot water switch was used. However if the heating switch was used, the pump would stop and one of the motorised valves would buzz. Manually opening the motorised valve made no difference.

So what is likely to be going on here? On Christmas day my thoughts were that the boiler was faulty. Today it looks like a motorised valve is now (also?) faulty, but I'm not sure the valve alone can explain all the problems.

The boiler is a Gloworm Fuelsaver, last serviced 3 weeks ago. The programmer and motorised valves are Honeywell.

Any suggestions gratefully received! I have service cover on the boiler, but not on the programmer or the motorised valves.

 

[Terry lambert]

If the honeywell valve has a little bobble on the top of the silver box, put in a new power head.

If the silver box is smooth, ( and four screws holding it on to the valve body) you will need to change the whole valve.

Which means draining down

 

[SomebodyElseDoIt]

The Honeywell is a V4043H1056. It does have a bobble, and the cover is held on by just one screw. I think that it is head-replaceable without draining down?

(editted as the bobble was more subtle than I was expectring and I hadn't spotted it)

 

[Terry lambert]

The one screw your looking st will be for the cover.

Your valve head should have two screws holding it to the valve body.

Lock the valve open and turn off power to system before replacing

 

[SomebodyElseDoIt]

Thanks, that is really helpful.

I've removed the whole buzzing head, and taken the cover off the other one for comparison. With the power back on again, I can see that the non-buzzing head moves its ratchet when I switch the hot water on - when it reaches the microswitch I get hot water. When I switch the heating on, the buzzing head buzzes, and the motor does not turn. Hence the microswitch does not get depressed and the heating does not start. If I depress the microswitch manually (carefully bearing in mind that the power is on!) the heating starts.

So I definitely need a new motor, possibly easiest to get as a whole new head.

The question now is, can I assume that the boiler is in fact OK?

 

[RigidRaider]

As with modern cars, many major systems failures are caused by faulty peripheral systems sending the wrong signals.

 

[Terry lambert]

If the mechanism is fine, just get a replacement motor. Easy to replace and cheap as chips

 

[SomebodyElseDoIt]

Even cheaper than chips as it turns out my service cover does include the valves!

Now fixed, and it was indeed just the motor.