boiler tripping out

doubtfir3

Hi All,

I have a grant boiler which was serviced last summer.

The house is approx 1500 sq ft with radiators upstairs, underfloor heating downstairs and standard hot water (heated through boiler). All controlled by a heatmerchants system.

I found that the boiler would occasionally "stop out" and have to be reset before, but it seems to be happening a lot more recently and of course as you can imagine there's no hot water or heating on as a result and the house is cold so I'm noticing it more in this current weather.

I also notice that I have to top up the closed loop with water more often that I feel I should have to using the valve in the hot press... and I'm not sure where:

a) the water's going to
b) why the boiler is tripping out

Any thoughts or suggestions on things I can check before I call in the plumber? (I'm not bleeding rads so that's not where the water pressure is dropping in the close system).

Thanks

jimf

when you say you have to reset the boiler is it the red button on the burner control box or the little pin button on the boiler control stat under a screw off cap

doubtfir3

jimf wrote: »

when you say you have to reset the boiler is it the red button on the burner control box or the little pin button on the boiler control stat under a screw off cap

Hi Jim,

It's the pin button under the screw-off cap.. I've loads of oil in the tank and good flow so its not that..

jimf

well its not a burner issue but a problem related to your closed system best have your plumber call and have it checked could be a number of things

jjf1974

doubtfir3 wrote: »

Hi Jim,

It's the pin button under the screw-off cap.. I've loads of oil in the tank and good flow so its not that..

That button trips when the boiler overheats.

shane0007

You have a leak somewhere on the system or the expansion vessel is split and water is exiting through the safety valve.
The water level within the boiler is lowering and therefore when firing, turns the water within the boiler to steam, which then trips the high limit stat.

First off, check at the boiler the automatic air vent on the boiler. They are buggers for leaking. Then check the circulating pump valves for weeps. The slot type are also notorious for leaking. Check the 3 bar safety valve for wetness/dripping. Finally, check the expansion vessel. Press the air nipple by pressing with a small pin or screw driver. If air comes out it may just need re-pressurising but if water comes out it is split.

kscobie

shane0007 wrote: »

You have a leak somewhere on the system or the expansion vessel is split and water is exiting through the safety valve.
The water level within the boiler is lowering and therefore when firing, turns the water within the boiler to steam, which then trips the high limit stat.

First off, check at the boiler the automatic air vent on the boiler. They are buggers for leaking. Then check the circulating pump valves for weeps. The slot type are also notorious for leaking. Check the 3 bar safety valve for wetness/dripping. Finally, check the expansion vessel. Press the air nipple by pressing with a small pin or screw driver. If air comes out it may just need re-pressurising but if water comes out it is split.

On the ball Shane, the high limit stat is tripping out because there is air at the top of the boiler. You need a good plumber to find where the water is going, otherwise there would be further problems down the line.