BOILER INCONSTSENTLY TURNING OFF AND ON!

[jackthom]

It sounds like the motorised valve and programmer are behaving as you'd expect and I can't really see how they would be likely to cause the problem.

For CH only the 3-port valve is powered across into position and then held there by a small electric current. I doubt it will ever be allowed to fall back to it's resting position in your system (hence the slack feel in the lever) unless the power is switched off completely. The unit will feel slightly warm consuming something less than 5 Watts in this state.

If you are happier having it "resting" (overnight for example) just power off the system for a short time to let it resettle and you'll be able to feel the difference in spring on the lever.

 

[Tubbsup]

Many, many thanks for your reassurance Jackthom.

I have just done a bit of experimenting with the 3 way motor valve:

1) Firstly, the CH hadn't been on since last night; the valve lever was slack and could easily be manually moved left and right; and then returned to the left position.

2) Turned up the wall/room stat to fire up the boiler, with the boiler working the lever is as above, i.e. slack and can be easily moved left and right. Then I manually return it to the left position

3) Turned room/wall stat down to turn of the boiler; then I turned off the CH at the power switch; the valve makes a whirling sound, and the valve lever, though easily moved, only moves to the half way point along the lever slot.

4) Turned the CH power switch back on, no whirling sound and lever still can only be moved to the half way point along the slot.

5) Turned up the wall/room stat, the boiler fires up; I'm not near the valve to hear whether it made the whirling sound again but when I try the valve lever it has returned to being easily moved left and right all the way along the lever slot.

I hope the above makes sense.

As the boiler is behaving itself at the moment it's fair to say the motor valve is operating as it should, as you said Jackthom.

The interesting question still remains, as to why has the boiler turned itself on and off in recent days?

But these discussions have been very helpful in helping me understand my CH system a bit more.

 

[JimMelrose]

Excuse me for intruding on your topic but do you know the operating water pressure range for the boiler. I can't find my manual and I think my boiler is operating at low pressure.
Thanks

 

[Tubbsup]

Message for JimMelrose,

I haven't time to check through the manual today but I will look into it tomorrow and write back.

 

[Tubbsup]

Hi Jim,

With regard to water pressure you asked about, there are details in the manual under 'Water flow rate and Pressure Loss'. Can you tell me what NF figure your particular boiler is as the details differ for each NF boiler. The NF numbered boilers are 30, 40, 50, 60, 70 and 80.


Does this mean you have a Ideal Classic NF 60, as I do? If you do, you may be able to help me. I have taken the outer casing of the boiler off and when looking at the heat exchange there's a wire/lead going in to it at the top left hand corner - do you know what this lead/wire is for?
The manual drawing is for an NF 30 which doesn't have the relevant wire/lead in the picture.