boiler won't stop! potterton suprima 60l

[croyden]

well i know the norm is for people to complain about being too cold but we're too darn hot!

my boiler is situated on a cold wall in a bare loft so have been used to hearing the frost protection kick it into life once or twice on cold nights, so in preparation for the cold snap apparently coming i bought some new pipe lagging yesterday (the foam stuff) thinking i'd replace the thin stuff on the pipes immediately entering/exiting the boiler. did this no problem where i could, certainly didn't dislodge or snap anything as far as i can tell, but on it's next cycle it just stayed on. checked and reset the timer switch, turned down the thermostat etc but it just keeps going. last night i ended up just turning off most of the TRVs and thinking i'd deal with it today.

have been up there fiddling around with temp control, resetting the power etc and it just seems that there is always an external request for heat. if i turn it to off i get the flashing orange light meaning there's a request that is being ignored, if i turn the temp up boiler fires no matter how low i have it. have reconfirmed that the timer isn't asking, and reset it again, behaviour is still the same. the only other thing i can find slightly wrong is if i request hot water and heating the last couple of radiators won't get properly hot, but i suspect this is down to the pump not being man enough to do everything at once. if hot water request is cancelled those rads heat up fine.

i guess i'm going to have to get a professional in but just it's worth a quick post in case someone has a magic (and free) bullet! we have a 4 month old baby so haven't tried anything that might potentially leave us stuck - heat all the time is better than no heat (until the gas bill comes!). appreciate any advice.

simon

 

[gas4you]

Could you have knocked the frost stat to a higher setting so it brings the boiler in at all times?

Other than that check any motorised zone valves are switching off properly, or one could have a faulty microswitch in the head, so telling the boiler to fire all the time.

As for the last 2 rads , perhaps you just need to close the balancing valve (gate valve) more, which you should have fitted on the return from the HW cylinder.

This will let more of the HW in the system go to the rads instead.

 

[croyden]

hi dave, thanks for taking the time to reply

i thought similar, but don't think i jogged anything - i've tried to identify the frost stat before with no joy, thinking that if it was adjustable i'd make it a bit less trigger happy. having said that following the last reset i removed the new lagging and put the old stuff back on (shouldn't make a difference, but ... you know) the boiler went off a short time later, and has just come back on at the correct time, so fingers crossed it will behave itself at off time. many thanks for the gate valve tip, i'll give that a try once i'm happy the other problem's resolved.
simon

 

[WDIK]

Simon, it does sound that the lagging may have reduced the aount of heat escaping into the area where the frost stat is, causing it to overide the boiler on.

if you do find it, turn it down, so that it activates at a lower temperature, remembering that the stat operates in reverse to a standard call for heat stat.