it can boil if the thermostat has gone
it won't turn the pilot off
Exotic pilot light problem
- Thread starter palmyra
- Start date
it can boil if the thermostat has gone
it won't turn the pilot off
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Which then brings me back to initial theory: no overheat stat it seems, and the boiler stat only kills main burner as I hoped for (after all, it should allow the burn to continue bit later which needs pilot light) - therefore something, somehow decides to kill pilot, but in a temperature-dependent way only when boiler did get hot after a long proper burn.
So the only logical explanation could be somewhere a 'hiding' overheat stat, which doesn't show on schematic nor can see anything whatsoever going into the solenoid box at the front (except the mains lead, gas pipe, 2 thin tubes from what is the pilot light assembly hiding behind the window) and the thermostat control box.
I guess for one's sanity the chap should ring about his (probably useless part) and book a visit, as the symptoms vs. what we arrived at are quite weird.
So the only logical explanation could be somewhere a 'hiding' overheat stat, which doesn't show on schematic nor can see anything whatsoever going into the solenoid box at the front (except the mains lead, gas pipe, 2 thin tubes from what is the pilot light assembly hiding behind the window) and the thermostat control box.
I guess for one's sanity the chap should ring about his (probably useless part) and book a visit, as the symptoms vs. what we arrived at are quite weird.
will you forget about a non existent overheat stat and get the ASD checked
FFS
FFS
Something that either cracks you up or opposite effect: what does ASD stand for?
Is it what the manual calls lower sensing tube (and has a filter on it) ? if yes, will it then lead to such cut-off only after nice long burns? it doesn't seem to have a fit on its own for short burn.
Apologies if the PDF I found is wildly different terminology, trying to match its diagrams up to what I can at least see from front of boiler controls.
Is it what the manual calls lower sensing tube (and has a filter on it) ? if yes, will it then lead to such cut-off only after nice long burns? it doesn't seem to have a fit on its own for short burn.
Apologies if the PDF I found is wildly different terminology, trying to match its diagrams up to what I can at least see from front of boiler controls.
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atmospheric sensing device
thats what cuts out the gas valve
thats what cuts out the gas valve
It's an oxy pilot mate, it senses that there is no or little oxgyen in the flue and tries to pull the sensing flame towards the oxygen that is there thus extinguishing it and then putting out the pilot.
The more POC going up the flue the less oxygen there is which is why your pilot is going out on long burns.
You need an RGI in mate.
The more POC going up the flue the less oxygen there is which is why your pilot is going out on long burns.
You need an RGI in mate.
totally repeating myself: thanks heaps - again, really.
Lightbulb indeed - good news is then next week he may not poke around for N visits and N thermostats + whatever
One thing that surprised me anyway was that watching the pilot right after the burner stops, couldn't see any change in the pilot flame prior to the might click cutting everything
It certainly decides to go 'no oxygen' once the boiler cuts out from house thermostat (doesn't do it while burning is on), so it was a bit counter-intuitive in terms of the sequence of events.
Lightbulb indeed - good news is then next week he may not poke around for N visits and N thermostats + whatever
One thing that surprised me anyway was that watching the pilot right after the burner stops, couldn't see any change in the pilot flame prior to the might click cutting everything
It certainly decides to go 'no oxygen' once the boiler cuts out from house thermostat (doesn't do it while burning is on), so it was a bit counter-intuitive in terms of the sequence of events.
There are two pilots mate one senses the oxygen or lack of and the other heats the FFD or thermocouple.
Bit like if you burn a candle and shut all the doors and windows in a room with no ventilation what happens is that as the oxygen in the room gets less the flame on the candle gets longer, what's actually happening is that the candle is 'searching' for air to keep it from going out.
An oxy-pilot does exactly the same thing only when it (the pilot) moves towards the oxygen the sensor the pilot is heating gets cold and then switches off the gas to the pilot heating the FFD.
Capiche?
Bit like if you burn a candle and shut all the doors and windows in a room with no ventilation what happens is that as the oxygen in the room gets less the flame on the candle gets longer, what's actually happening is that the candle is 'searching' for air to keep it from going out.
An oxy-pilot does exactly the same thing only when it (the pilot) moves towards the oxygen the sensor the pilot is heating gets cold and then switches off the gas to the pilot heating the FFD.
Capiche?
it does, thanks- it matches 9.4 in the manual I have. Also explanation makes sense, clearly I see therefore just part of the picture through the window.
I might shelf the thermocouple he brings next week (I can only hope... "will ring as soon as part is in") and then redirect him, begging, in a totally different direction.
He checked the flue, measured air flow etc. so definitely, the problem should be this thing clogged, filter etc. rather than genuine oxygen depletion of some dangerous level (assuming his measurements/tests during servicing were indeed OK).
I might shelf
the thermocouple he brings next week (I can only hope... "will ring as soon as part is in") and then redirect him, begging, in a totally different direction.He checked the flue, measured air flow etc. so definitely, the problem should be this thing clogged, filter etc. rather than genuine oxygen depletion of some dangerous level (assuming his measurements/tests during servicing were indeed OK).
There should be permanent ventilation in your room so make sure the vents aren't clogged up or blocked by couches or furniture and it wouldn't do any harm to go and buy a COD (carbon monoxide detector alarm) however you shouldn't rely on one of these and the ADS, these units require proper servicing anually by an RGI.
yep there's a mighty vent near it, quite cold draft nowadays. I've been bringing in Southern Electric to clean and service it each year since I bought the place, this year switched to a checkatrade.com chap who lives nearbya and Gas Safe registered (S.E. said there 'may' be asbestos in chimney terminators as it's older building so they no longer cover the entire thing, hence my switch to someone else).
He serviced it this week so I find the coincidence of this sudden new problem quite interesting... so hoping something is clogged up, as nothing changed around the boiler and he was happy with the measured ventilation, draft and flue extraction when he tested with smoke etc.
He serviced it this week so I find the coincidence of this sudden new problem quite interesting... so hoping something is clogged up, as nothing changed around the boiler and he was happy with the measured ventilation, draft and flue extraction when he tested with smoke etc.
H
holty
flues can get be checked at any time to be operating good.same time after a bird likes to fly into it.
Watching all this "discussion" when whats needed is an assessment of the boiler is getting nowhere!
Any o/h stat is identified on the boiler itself. If one were fitted it would have a lead connected to the thermocouple lead.
Of course you should not need to be in any way involved because your engineer should be totally competent and able to diagnose and fix any boiler faults.
Unfortunately your engineer seems to be rather less than competent. Boilers are pretty simple appliances and its usually easy to identify any faults.
Tony
Any o/h stat is identified on the boiler itself. If one were fitted it would have a lead connected to the thermocouple lead.
Of course you should not need to be in any way involved because your engineer should be totally competent and able to diagnose and fix any boiler faults.
Unfortunately your engineer seems to be rather less than competent. Boilers are pretty simple appliances and its usually easy to identify any faults.
Tony
H
holty
agile you seem to have a thing about the overheat stat which im pretty sure wasnt available on this model. yet your right if you cant fault find this model ON SITE your pretty screwed as to figure how a simple boiler works.
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