Grandee oil boiler cutting out

Hello
I have a Grandee oil boiler model G1 with a Sterling burner.
We have a actuator valve (3 way) supplying the hot water tank and/or radiators.
The boiler has been working for around 10 years without any problems so guessing I am lucky there, only thing we had done was to replace the nozzel and get the soot cleaned out at intervals.

Brief problem is, fires up for 10 secs then cut out, tried the reset button again 10 secs then cuts out.

I did get it to work this morning from cold after it cut out for the first time of switching on, using the reset button and it stayed on coming on & off on its own for about an hour, I moved the thermostat dial to check it was triggering o.k. worked fine, I thought it may have been a one off where it cut out but now its back to the 10 sec cut out

can see oil in feed supply to pump, the water pump pushes the water through the boiler as I can hear it, when it does fire up for those 10 secs all sound o.k. but there is clearly a fault being flaged up for it to cut out.

As I got it to run for a hour this morning it would indicate that many parts are working.

could this be a air/oil mixture ? photo cell problem, then how would it change to a point of tripping out ? can see almost a long list of maybe's here.

Not sure if this fault is common to many different boilers ???

Would appreciate any engineers advice please.

Thanks.

If the burner is lighting and you hear the bang. It comes down to dirt on photo cell. Or photo cell fault not detecting the light. Or pump solenoid valve/solenoid cutting the fuel off.

Hi dcawkwell
Thanks for your reply about my problem with the boiler cutting out.

I removed the lamp/bulb which was simply a pull down with two fingers, noticed it had some dust buildup on it cleaned it with a clean brush, refitted and it worked and is still working today ))

I am guessing that this lamp/bulb must be read by a light diode/sensor internally ??? I have not removed the two screws that the lamp slots into as yet, not sure I should in order to clean the diode/sensor part that detects the light ???

One question I have, is the light sensor/diode wired to a fault sensor circuit that shuts the unit down ???

Maybe I will monitor it and see if all keeps working.

Just wanted to say "MANY THANKS" for your info as I had visions of trying so many things and running up a huge bill too.

DELTA16 said:

Hi dcawkwell
Thanks for your reply about my problem with the boiler cutting out.

I removed the lamp/bulb which was simply a pull down with two fingers, noticed it had some dust buildup on it cleaned it with a clean brush, refitted and it worked and is still working today ))

I am guessing that this lamp/bulb must be read by a light diode/sensor internally ??? I have not removed the two screws that the lamp slots into as yet, not sure I should in order to clean the diode/sensor part that detects the light ???

One question I have, is the light sensor/diode wired to a fault sensor circuit that shuts the unit down ???

Maybe I will monitor it and see if all keeps working.

Just wanted to say "MANY THANKS" for your info as I had visions of trying so many things and running up a huge bill too.

Click to expand...

The diode is a flame sensor it detects the light of the flame.
It is used before the control unit starts the ignition sequence to see
there is no flame and then again after the oil has been switched on
to ensure a flame has been established. Any fault on either signal and
the burner will shut down. A build up of soot will cause the burner to fire
and then shut down. It is a standard item to clean on the service.
Also a boiler that is badly adjusted and sooting will usually cause this
to soot up and then the boiler will fail.

Hi
Thanks for the technical info regarding the sensor diode.

I am intreaged as to why this little bulb is there ? I can appreciate the diode looking for the flame once ignition has occured and acting as a safety cut out if ignition fails.

Does the diode sensor need to see some light level all the time i.e. before ignition and during non-ignition periods.

As the bulb was dusty I am assuming the diode sensor will be sooty/dusty also, is it just a case of wipeing the sensor and replace i.e. no calibration needed.

The boiler is fired up the exhaust looks clear, no signs of any smoke so I am assuming the mixture is good hope thats a correct assumption to make.

Thanks for any info.

the photo sensor is a safety device , when we service them we pull out the photosensor & cover it with our hands to check it locks out , it checks the flame is there . Some soot quicker than others & clean combustion will slow the sooting of the sensor . Regular servicing of all boilers is important

Hi Murf520970
Thanks for the info, reason I have an interest is that I spent 25 years as a service engineer on the road (nothing to do with boilers) but have an enquireing mind as to how things work.

Having read verious info here and elswhere I now gather that the photocell I removed and cleaned is the complete unit, I had assumed that there was another part to the photocell inside the burner.

Does the photocell see the ignited flame as a higher light level than the bulb ? and there fore says ok all is well keep burning.

Thanks for any info

bulb ? the photocell is on the end of the small plastic stalk enclosed in a small glass cover , it just sees the flame through the hole in the burner . Not sure of technical complexities of it ,as in what the gadgetry is but we can check the resistance of it so i would presume its a resistor of some type ? i just know the fault scenarios .The Burnermen would know what it is . The control box is the brains of the boiler & the photocell is a single unit .

Hi
Thanks for the info, I may be getting on in years but always happy to learn something new, yes, I assumed it was a "bulb" as it looks just like a small minature meter bulb that would be used for a backlight.

Shows just how wrong I was calling it a bulb !!! just did not appreciate its full operation until you said how it works.

Thanks.