Oil burner locking out - Riello 40

[SimonH2]

I'm starting to look into a few issues at church - there'll be another post along (when I get some diagrams drawn) relating to hydraulic issues - but an immediate one is that the boiler burner is locking out rather more frequently than it should.
It's a Riello 40 G5 (28 to 60kW) running off regular heating oil, and firing into an old cast iron job that was (we believe) second hand in 1972. Last year it got repaired (leaking oil pump) and was then working fine. But now the weather is cold, it's locking out rather more often than it should.
Yesterday I was there doing some odd-jobs and while the frost stat had kicked in and the circulation pump was running, the boiler was locked out. Fired up when I reset it and ran fine.
I tried turning it on and off a few times and it "just worked fine". I've had a text this morning from one of the churchwardens to say it was locked out again this morning and he'd reset it - so just about time to get the place warm before the service at 11, last service we had nearly finished before it got warm as no-one knew what to look for

Any thoughts on what the issue might be before we get someone in again to look at it ? Could it simply be the oil that's cold and a bit more viscous than when it was repaired in summer ?

 

[oilboffin]

1 look at the photo cell check it's clean change it if it looks really old.2 check pump pressure and nozzle make sure the nozzles clean it should be changed every year.3 change the coil on the pump it helps to open the valve to allow the oil to the nozzle.4 change the capacitor this helps the motor to start.these things would be checked by an engineer. Bob

 

[SimonH2]

Thanks. They are calling the engineer in to have another look at it, we'll see what he says. I'll try and be there when he is so I can talk a few things through with him.
As is probably the case with most small churches, for many years it's gone without anyone with any technical knowledge and relying on "getting people in" as things break - except for the boiler which they've been getting services every year. I've started getting involved, and trying to get understand the intricacies of the various systems and the years of ad-hoc repairs and alterations.

 

[SimonH2]

Heating engineer came this morning. The piston that opens the air flap was leaking a little - and he's guessing that it's been letting a little air in when shut down for a while. We don't need it in our installation so he's going to just blank the oil port and leave the flap off - we'll see if that makes any difference.
He checked to be sure, there's a good flow of clean oil from the tank.

 

[SimonH2]

Well it's been OK so far - church was nice and warm this morning