Puzzling trip out on Trianco TRO

[WHPES]

Problem I have with a vintage TRO

The burner kept tripping out every few hours. Burns well normally, good readings, no soot. The normal thing of course is to assume it's the solenoid coil which I did. Continued to trip but less frequently, maybe twice per day. Changed the solenoid valve as well and it's improved but still trips a couple of times a week. The pump isn't that old (Danfoss BFP type used to replace the old MSLA type about 3 years ago).

My next thoughts are:

Dodgy pump
Photocell
Nozzle

However the infrequency of the trips has me puzzled

Anyone else had this problem? What did you do?

 

[kimbo]

Could be transformer or maybe oil filter but I guess you would have checked that.

 

[Best]

Assuming everything obvious seems good ( strong spark, strong & quick to start motor, etc) then I would say control box or photocell. Either can do this one or two days ok, then tripping suddenly. Photocells will catch you out as you don't see this too often.
BHO11/12 boxes when fairly old have the contact points inside them burned, like you got with car points years ago (for those old enough to remember :grin & all they need is a rub between them with emery cloth.

 

[Roger Welton]

I would agree with control box if all usual boxes have been ticked.

 

[WHPES]

It's puzzling as the boiler can run for a couple of days before tripping.

Trianco tech support said it was most likely the fuel - they are getting asked about this problem quite regularly at the moment.

Their proposal was to firstly to set manually with a more orange flame (use smoke pump and back off to 0-1) or use a more sensitive photocell and if that doesnt work, drill a hole through the blast tube in line with the photocell.