Central heating not firing up - something obvious?

[realstokebloke]

Hi - that time of year when the wife starts saying "i'm cold" & the heat goes on : (

But not this time - although when the HW is "on", on the control / timer unit, the boiler fires up & off we go (so the boiler "works" & we have HW)..when the CH is "on", on the panel, it doesn't seem to 'call' for the heat & the boiler doesn't fire up or the pump run?

(The light on the panel goes "on" and I've no reason to think that's faulty.)

This is a conventional, vented Baxi Solo with a loft header & HW cylinder.

I did put a shower & Salamander pump in, in the summer but didn't mess with the CH as such.

We did put in a towel rad in the bathroom - but that was fine when tested (the CH fired & worked).

& the only other thing that's different is that i have isolated a small hall radiator as the drain off valve was seeping - but i am sure i have isolated rads (to take off & paint) before & the heating still works?

So, is there an obvious 'check' or ' you've forgetton to...' that i'm misssing here?

Any clues appreciated, thanks : )

[nysk2008]

have you checked the diverter valve is moving over?

[b26b]

Possibly one of the following. Room stat, Mid Position valve Programmer (less likely). You can get some heat for now by 'latching' the valve open (google it). It will mean that when the HW stat is satisified the boiler will turn off thou. If you are handy with a multimeter you can trace the fault starting in the wiring centre. If not get the experts in to cock it up!!! I will go for a duff Mid Position valve or Room Stat (particulally if its electronic).Let us know who you do nothing worse than a cold missus (depends on the circumstances!!)

[realstokebloke]

On the motorised valve you mean nysk?

If so & you mean the paddle / lever thing, I'm still not entirely sure what you mean "moving over" tho' sorry.

I read ano post below & so did try pulling it (the paddle / lever) away from the cylinder & it seemed to 'resist' but now, ghaving done that, it seems to just hang there with no resistance to go back / forth (it is installed with the lever pointing down).

There is a paddle indicator on the side which sits between A & B in the middle next to a triangle symbol.

That any help?

[realstokebloke]

Possibly one of the following. Room stat, Mid Position valve Programmer (less likely). You can get some heat for now by 'latching' the valve open (google it). It will mean that when the HW stat is satisified the boiler will turn off thou. If you are handy with a multimeter you can trace the fault starting in the wiring centre. If not get the experts in to cock it up!!! I will go for a duff Mid Position valve or Room Stat (particulally if its electronic).Let us know who you do nothing worse than a cold missus (depends on the circumstances!!)

If your "mid position valve programmer" bit is the same as my reply to the motorised valve, then i have tried as above - the lever seems to be just 'hanging' there but the indicator shows it to be in the middle, yes?

If it's the electrics i'm stymied : (

[nysk2008]

Ok, set programmer to CH on with room stat calling fopr heat - turn HW off if programmer allows, does the paddle on the motorised valve move at all?

[realstokebloke]

Ok, set programmer to CH on with room stat calling fopr heat - turn HW off if programmer allows, does the paddle on the motorised valve move at all?

Thanks nysk, have done that - but no, the paddle just hangs there like a limp **** somewhere in the middle?

In other words, it has none of the resistance i felt when i first moved it away from the cylinder (see above).

It seems to making a 'humming' noise like there's juice going to it & it's trying to do something?

[nysk2008]

so, the diverter valve has an engergised and de-energised. almost all systems are hot water prority and will remain on port b until the hot water has been statisfied, it will then move to port a (C/H). If the valve fails it will generally fail in the de-energised position (normally HW). As the CH has not been used for a while it could have seized and can be freed up by removing the acuator head and turning the spindle with a spanner. Replacement of the head would be my first port of call though

[b26b]

agree nysk2008, explained it better than me. Word of warning if the head is the removable type then fine whip it off. If it has a metal lid you will need to take this off to remove head. Power off obviously!! If the head is mounted on the brass body with two screws at opposite corners then remove. If the head is mounted on the brass body with 4 screws then removing may pull spindle out of brass body and a stream of water will quickly follow. Removing metal head valves will mean you will need to re build it. For the uninitated its not recommended, your call on that one!!

[realstokebloke]

so, the diverter valve has an engergised and de-energised. almost all systems are hot water prority and will remain on port b until the hot water has been statisfied, it will then move to port a (C/H). If the valve fails it will generally fail in the de-energised position (normally HW). As the CH has not been used for a while it could have seized and can be freed up by removing the acuator head and turning the spindle with a spanner. Replacement of the head would be my first port of call though

Thanks nysk, when i have put both the HW & the CH on, something's definitely 'cooking'.

I took the cover off the indicator and manually 'helped' it down to B (I take it A = HW & B = CH?) & yes there's HW getting round (a few gurgles in the pipes mind so needs a good bleed no doubt).

So maybe it just needed a 'nudge into the right position? & i'm not competent enough to remove the actuator head & turn it with a spanner - mainly as i don't know which bits they are - but mnaully forcing the indicator may have had the same effect?

Not sure if it will do the same for me with just the HW yet & can't leave the cover off to force it to B every time (i can just see the mrs being happy with that one : ) )

[realstokebloke]

agree nysk2008, explained it better than me. Word of warning if the head is the removable type then fine whip it off. If it has a metal lid you will need to take this off to remove head. Power off obviously!! If the head is mounted on the brass body with two screws at opposite corners then remove. If the head is mounted on the brass body with 4 screws then removing may pull spindle out of brass body and a stream of water will quickly follow. Removing metal head valves will mean you will need to re build it. For the uninitated its not recommended, your call on that one!!

I hadn't seen this one when replying above but confirms i might need to call a man who does (the jet of water puts me off a bit : ) )

So, sorry to be thick, but how should this valve work?

The paddle (I assume) swithces between A & B automatically then?

I ask so i can keep an eye on it now after some bleeding and report back later - thanks both.

[nysk2008]

B=HW, A=CH mate

[nysk2008]

forgot to mention but if you put something in the "i need a plumber / gas engineer" section I am sure there a lads local to you - only if you cant get it sorted that is.

[realstokebloke]

B=HW, A=CH mate

Mmm. Odd. it goes down (in this case as it's mounted vertically on the pipework) to B easily enough but seems reluctant to got 'up' to A.

Whereas when on B it seemed to start HW going round the system.

It's not possible some herbet has put it on the wrong way is it?

Oh, & not guilty : )

As above could you just tell me in words of one syllable what it's supposed to do then i can keep an eye on it, thanks !

[realstokebloke]

B=HW, A=CH mate

and when i 'help' the indicator (& presumably, the valve inside itself) up to B, i has that same resisitance - but will go - but straightaway drops 'down' towards A again.