Intermittant fault on a Grandee 1 WM oil boiler

[DeltaT]

It's locking out on cold start some times, the photocell is OK, it's as clean as a Nuns knickers, the oil pressure is fine, electrodes are fine, no air in the oil line, it's had a new nozzle & control box. Of course, it'll never lockout when our guy is standing over it!!!

The appliance is 10 years old & has a Monoflame burner.

Any thoughts Gentlemen?

 

[casius66]

Sounds like it's over aired, what CO2 reading did your guy get on it? and why did he replace the control box?

 

[DeltaT]

Thanks casius66, that's been checked.
Sorry, I'm not sure what he got as regards CO2?

I also asked about the control box & he said 'he had one in the van'??
If you're an employer, you may like me, fail to understand answers like that and after years of hearing them come to terms with it!

 

[Boilerman2]

The joys of employing engineers eh!!
The Grandee is a piece of ****e to be honest, the ecoflam minor burner is just as bad, so as a combination

Check the ignition Transformer (cofi type) for arcing where the HT Leads plug on to it, these can sometimes arc when cold & damp, PE cell could be faulty is the control box Landis & Gyr (Seimens) or Satronic (Honeywell)?
Satronic boxes sometimes go wobbly, what we do with problem boilers is assign One Engineer, and try swapping parts one at a time leaving it for a trial untill either the fault is fixed, or your engineer quits!!

Good luck my friends (I'm so glad it is not just my company that has these sort of problems... you are not alone my friend

 

[DeltaT]

Thanks for your reassuring words Boilerman2. I'll pass these comments on.
Unfortunately it's for an older customer, so we want to get it sorted for the old dear.

 

[gassafeengineer]

i guarantee it is one of the following most likely to be the first

Coil on the solenoid valve after it has been in operation and warmed up it is dropping off shutting the fuel supply off

or motor has a flat spot when warm, once the motor stops in this position the resistance is to high for the motor and capacitor to start,

oh and by the way that is the worst boiler ever made in a garage in birmingham replaced one other week only 3 years old SAVE FOR A NEW BOILER QUICK

 

[DeltaT]

Well, apparently it pre-purges OK, so the solenoid is a good call. Thanks for that, it did cross my mind also.

 

[Boilerman2]

I thought it had a COLD START problem, how will that be the solenoid coil? they normally play up after 1/2hr or so??? but it could be anything, it could be the capacitor on the burner motor

 

[DeltaT]

Good point Boilerman2, I think I'll have wee look at it myself. Thanks