oil boiler shuts down after about 10 mins

[bus]

well i have just joined and this is my first post and sadly i start with a problem i have a camry oil boiler its about 14 years old it shuts down after about 10 -2o mins on the heating cycle the room stat is still asking for heat and so the ch pump still runs. it appears that one of the stats in the top of the boiler housing is getting to it max temp and shutting the boiler down.
i have recently fitted a new ch pump a one new rad and also fitted trv's to 4 0f the 6 rads that i have in my bungalow i am confident that i have removed all the air from the system via the rads and the bleed valves in my loft.
i seem to get hot water ok and the rads get lovely and hot until shutdown.
i have an open vented system any help please.......

 

[wiss]

cant really see a problem, if you say everything is getting hot and boiler is shutting down on boiler stat thats norm, i take it you dont mean overheat stat - are you having to press the reset to get the boiler on again???

 

[bus]

cant really see a problem, if you say everything is getting hot and boiler is shutting down on boiler stat thats norm, i take it you dont mean overheat stat - are you having to press the reset to get the boiler on again???

the stat that is situated in the top left of my boiler is getting hot and shutting the boiler down after about 20 mins the boiler will start up but then shortly after will shut down again the room atat at this point is still asking for heat and because of this the ch pump stays on after the boiler shuts down this never used to happen the room stat would always shut the boiler down when the temp in the room had reached the desired setting .......

 

[oilhead]

If the room stat is still calling for heat, then the pump will still run. If the boiler stat is hot enough, then it will shut the boiler down, but the pump will still circulate the primary water. As the cooler water returns, then the boiler stat will cool down and start the boiler up again. What you describe would apperar to be normal, or have I missed something?

 

[Boilerman2]

Sounds perfectly normal to me after all if the boiler stat did not shut the burner off the boiler would boil up

 

[bus]

Sounds perfectly normal to me after all if the boiler stat did not shut the burner off the boiler would boil up

yes i understand what you are saying but if the room stat is set to 20 and the boiler shuts itself down well before this temp is reached that surely cant be normal i have had the boiler from new and it never used to shut down before the room stat had reached its desired temp could the stat in the boiler be faulty? i thank you for your opinion and advice

 

[Boilerman2]

How hot exactly are your radiators getting, check the temperature of the rads, then do the same at the boiler water jacket, it should all be roughly the same +/- 10'c, if the rads are much colder than the boiler then you have a circulation issue i.e pump faulty or similar, the burner should shut off at on low about 60'c and at full about 80'c I think you do need to check with an electronic thermometer!

 

[rieverjohn]

Hi Bus,
Going back about thirty years, I had a problem with an oil boiler which shut down after twenty minutes almost to the second. Called an engineer as I wasn't confident enough to look for myself. He proceeded to change just about everything changeable without success, eventually he removed the feed pump which had a float chamber similiar to a car carburettor, he opened up the float chamber and believe it or not inside was a very large flying insect like a mosquito. After removing this insect (dead by the way) the boiler gave no more trouble.
I can only assume that when the boiler was at rest(not running) the mossy would float up to the top of the fuel in the float chamber then once the boiler fired up it took twenty minutes for the mossy to fall into the inlet of the chamber thereby starving the boiler of fuel.
This is not a fairy story.

 

[leakydave]

Does the burner 'lock out' or start of its own accord shortly afterwards?