Warmflow Utility 70 - RDB 2.2 Burner - Help please oil guys!

[Andy4444]

Gents

Local calls me to look at a problem he's having with subject boiler (installed November 2007 with a pump change after only three months).

Anyway when I'm there the burner motor was running indefinitely, after 12 sec purge, without firing and no lock-out. Changed photocell and boiler fired but then went to lock-out.

So, changed nozzle, electrode dimensions spot on (getting nice spark), filter clean, purged pump, oil behind nozzle, 50 vac at motor on white, solenoid giving me approx 100 ohms. Put my gauge on pump, started motor and got circa 50 psi but then lock-out and no firing.

Spoke with Warmflow Tech and we agreed that pump should be replaced. So replaced pump, purged, and still the same, ie motor runs, 12 sec purge, strong spark, gauge shows about 50 psi and lock-out.

It now seems to be pointing towards control box (per fault finding flow chart) but before I do wanted to seek advice from any oilies that might have some ideas.

Cheers fellas

Andy

 

[Burnerman]

50 psi is way too low for the oil to atomise...presumably the blast tube / firebox is soaking wet? Do you think the motor is spinning up to speed, and is its drive coupling ok?
John

 

[Andy4444]

John

No there's a spark but no oil getting through nozzle (although oil present behind nozzle) so dry as a bone. Note your comment re pump pressure but according to Riello the pump washing pressure goes to 50 psi before solenoid opens and then pressure should go to normal operating pressure???? Are you saying it could be a motor/motor capacitor problem?

Andy

 

[Burnerman]

At the moment I think this could point to the solenoid coil on top of the oil pump - especially as you have replaced the photocell. Obviously there's no real way of telling if the pump valve is actually opening either - I would have expected the blast tube / fire box to be damp with oil if it was.
So long as the motor starts and rotates you can forget about it - the capacitor is obviously ok if it does this time after time.
As soon as the boiler lights see what pressure its running at - it should jump to well over 100 psi.
John

 

[Andy4444]

Thanks again John. So despite solenoid showing resistance it may be failing (I checked wiring at control box and it seemed OK)?

 

[Burnerman]

The coils do tend to fail, often when they get warm....I keep a spare just to change over - but the Danfoss one is much quicker!
John