possible problems with high temp stat??

[mck450]

Hello folks, I'm a bit stuck. I was over at my sisters house bleeding the oil system as it ran empty, its a Reillo burner, not to old by the looks of it. So I got it bled and the system knocks off after 10 mins or less, the stat on the boiler trips and it wont start up again til everything is cooled down after about half an hour. The stat wont even click when I turn it above and below the 75 degrees mark, but when its cooled down it will so I think its either a faulty stat or maybe the boiler itself needs filled again with water as it may be heating air in the system rather than water, the air relief valve seemed to have been stuck, i tapped it with a screwdriver and quite a bit of hot air started bubbling out. any ideas? would be greatly apprecaited

 

[tipintim]

pump not working???

 

[mck450]

pump not working???

would the burner even fire with a faulty pump? it seems to be working as there was oil coming out of the bleed scew

 

[mck450]

the boiler stat is a warmflow imit dual stat short probe,
it seems to work when cold, as i can hear it click when i turn the temp gauge up and down but once its fired up it and knocks off wont click on at all, even when i turn it up to 95. there are no other stats on the system, no trv's on the rads inside so everything is regulated from the boiler stat

 

[Dotty]

Not the oil pump! Go and check the circulating pump!

 

[mck450]

the pump was very hot, cant remember now what make of pump it was but there was a dial on it numbered 1-3, it was on the number 3

 

[snowhead]

You need proffesional help.

 

[mck450]

yes i've been told that before lol

 

[mck450]

the burner is getting oil. it will fire from cold, so it has to be a faulty stat, cant be the photo sensor because it shouldnt fire at all if that was the problem, the pump seems to be working because we are getting heat to the rads

 

[snowhead]

The stat is doing it's job, protecting the boiler from running with little or no water in the system.

i tapped it with a screwdriver and quite a bit of hot air started bubbling out. any ideas? would be greatly apprecaited

 

[mck450]

that's what I thought, after checking everything elseI thought either the stat is faulty or there is air in the system. My sis has just moved in about a month or 2, so if the rad are being heated before the system knocks of would it be the pump that is faulty or simply needs water added to the system? I haven't been in the roof space yet to check the tanks

 

[mck450]

plus the air relief valve was spewing out hot air when i gave it a few taps with the handle of a screw driver, its in an old wooden boiler house and looks like its seen a bit of corrosion

 

[snowhead]

If the rads are getting warm the circulation pump (1.2.3) will most likely be working.

Your next job, check the header tank in the roof space and don't fire the boiler again till you have water coming out the air relief valve.
And turn the pump off when you open the air bleed.

 

[mck450]

thanks lads, great input early on a sunday morning, I'm off to try the tanks in the roofspace

 

[mck450]

If the rads are getting warm the circulation pump (1.2.3) will most likely be working.

Your next job, check the header tank in the roof space and don't fire the boiler again till you have water coming out the air relief valve.
And turn the pump off when you open the air bleed.

the air relief valve on the boiler you mean? there was hot air flying out of it when i taped it, seemed to be stuck possibly corroded

 

[Best]

Be careful - is it a sealed system with a red expansion vessel & a filling loop & pressure gauge somewhere? May need filled with water.
If not a sealed system, & has a small expansion tank in attic, then tank could be empty or the feed pipe leaving it could be blocked.

 

[mck450]

no it's an open vented system, was over earlier and discovered the f&e tank was bone dry, the ball cock had seized so after manually moving it open and closed it freed itself up. So it has drawn air into the system which would explain the steam coming out of the air vent at the boiler. The circulating pump may be damaged i think because its still tripping out the stat. Night mare, I just told them to get the landlord to get his finger out and get a plumber

 

[Bunker]

Be careful - those AAVs are easily stuck open with bits of crap. Check the airing cupboard (or 'hot press' as Ive just learnt) for a manual air vent, sometimes you get an airlock down to the 3 port valve (if there is one) which can stop circulation and then the boiler will over heat.
Are ALL your rads getting hot - upstairs and downstairs? If upstairs are hotter than down, it'll be a circ pump failure, but as said above, if your getting air out the top of the boiler - that will be the problem.

 

[mck450]

Be careful - those AAVs are easily stuck open with bits of crap. Check the airing cupboard (or 'hot press' as Ive just learnt) for a manual air vent, sometimes you get an airlock down to the 3 port valve (if there is one) which can stop circulation and then the boiler will over heat.
Are ALL your rads getting hot - upstairs and downstairs? If upstairs are hotter than down, it'll be a circ pump failure, but as said above, if your getting air out the top of the boiler - that will be the problem.

There was a bit of heat getting to the rads, its a bungalow and i checked the rads were all bled. There is no 3 way valve. the boiler heats the rads and hot water and the only stat is on the boiler, its a shambles of a system! The F&e tank was dry when I checked it, the ball cock had seized up a bit. My sis has just moved in to the house but the heating was working fine until it ran out of oil, i bled the oik and got the boiler fired but it only runs for 10 mins from cold and knocks off, The only thing that's left to check is the circulating pump. still no sign of the landlord getting a plumber out either