boiler not turning off correctly

[alexjp]

i have a three maybe four year old valiant combi boiler,everytime the heating is switched on we can never get it to turn back off by using the control switch on the timer,it used to be that the the only way to turn the heating off was to switch the boiler completely off and then back on,but now even that does not work every time!!

i have noticed that the boiler electric supply is actually wired in with the lights on the main fuse box but do not know whether this would cause a problem as we live in a smallish sized flat

any help in this matter would be greatly appreciated

 

[chrishutt]

Is the programmer built into the combi control panel, or is it a separate item wired in? If the latter, I would suspect a programmer or wiring fault (if you're competent with electrics, you could take a closer look at wiring and report what you find). Is the boiler a turbomax?

 

[alexjp]

the proggrammer (timer) is a seperately wired unit and to be honest looks a little older than the actual boiler itself,
the boiler is a valiant turbomax 824 e

 

[chrishutt]

Actually it's Vaillant. If you can't describe existing wiring, we aren't going to make much progress. but don't start opening boxes unless you know what you're doing (catch 22 ). Best get a good heating engineer in - there might be someone on the forum in the Durham area.

Just re-reading your first post - when you say heating continues when you switch it off at programmer, do you mean the boiler continues to fire (flames showing) or just that the boiler continues to make a noise (e.g. pump running)? If the former, how much longer does the boiler run/fire? Indefinitely or for so many minutes?

 

[alexjp]

thank you very much i know a little about electrics but would struggle i think probably go bang a few times as well and get beaten from the wifey !!

i live in spennymoor (county durham) and would appreciate a quote from someone if anyone can help me out

 

[chrishutt]

just read the second part of my post above (added after your post).

 

[alexjp]

the boiler still fires and does not turn itself off at all even if you turn the power off at the boiler itself and on the timer the radiators still stay on. in the past we have turned the boiler off gone to bed only to find the heating still on at three in the morning.

 

[chrishutt]

sounds like the wiring's crazy. Can you say specifically which switches you turn off on the boiler, just to be sure you're not doing something wrong?

 

[alexjp]

as you look at the boiler there is a green on/off switch at the bottom right,that is the switch that at the moment we are turning off,but most of the time even then the heating stays on,we tried using the switch on the timer before doing this but it had no effect at all

 

[ChrisR]

Could be that the "switched live" supply is taken from the mains instead of out from the boiler to the clock/thermostat and back in again.

Not sure what it would do on a Vaillant.
With some boilers the circuit board would blow up the first time you turned it on, whereas other boilers would work fine.

Haven't got a frost protection thermostat have you?

 

[alexjp]

no frost protection thermostat,could the problem have anything to do with the way that the boiler is wired up to the electric mains supply at the moment it runs into the lights fuse.

 

[chrishutt]

It doesn't really matter where the boiler supply is connected on the consumer unit.

As ChrisR said, you probably have the switched live from the programmer by-passing the main boiler on-off control, but there must be another fault - possibly with programmer. Only an engineer on site can sort it out.

 

[alexjp]

many thanks for all your help i think at the moment the best plan off action is to get a decent heating engineer out to have a good look at the blasted thing sick of the flat being like a sauna..

once again many thanks for your help