Heatslave lock out - please help !!

23 Oct 2008
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United Kingdom

Hope one of you can help with a problem on my Worcester Heatslave 15/19, thats about 10 years old ??

p.s. - I'm a fireman by trade, not a heating engineer, but keen to learn :) I feel like a heating engineer because of the many times this crock of sh*t appliance has given me trouble !! :mad:

It is on permanent lockout.

When I switch it on, it trys for about 15 secs then locks back out.

I've taken off the the burner, checked the electrodes and nozzle. The nozzle gap to electrode, and electrode gaps are ok. The electrodes are sparking, however the oil coming out of the nozzle seems to be a "squirt" rather than an atomised spray. The burner fan is rotating. I've cleaned the photocell and that seems ok. I've bled the oil pump and there is oil coming through the pump. I've had the filter out of the oil pump and that's ok. I'm on a "Tiger-Loop" system.

So it's obvious to me that when I reset the lock-out, the system is trying to go, but there is something stopping it. I know that the electrodes are sparking, but not igniting the oil so the photocell is telling the system to shut down.

So I feel the problem lies with the oil pump. I'm curious to know what the solenoid on the oil pump (Danfoss BFP41) does, as I've heard they can be faulty. I also think the oil pump is not delivering the pressure to atomise the oil so the spark can catch.

How would you problem solve this. Start with a new solenoid, or just go straight for a new oil pump ??

Any help would be greatly appreciated, thanks.

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Hi Graeme
The first thing to do is to check the oil pump pressure which should be around 120 psi. If the oil is just dribbling out, no way will it ignite.
At least there is oil coming out of the nozzle, you say - that suggests that the pump solenoid is ok. If no oil is passing, then the solenoid coil is number 1 suspect.
John :)
Thanks for the advice, I've already tried 2 other nozzles that were replaced at various services, but no change.

It does sound like a pump pressure thing to me. Would an engineer try to fix the pump, or would he just replace it ?
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For info - your burner should be a Electro Inter B9B.
Your boiler can output between 15 and 19 kw.
There is a choice of 4 nozzles, depending on the output of your boiler.
If you'll tell me which nozzle you have, I'll tell you the ideal pump pressure.
(Loads of pumps are changed for the wrong reason...yours is pressure adjustable at the front, with an allen key).
John :)

the nozzle is an 80 H.

When I pull the burner so far out and watch the oil flow from the nozzle, it looks like a "squirt" with big droplets. Should this be an atomised spray ??

I understand why the electrodes wouldn't ignite droplets with oil that has such a low flash point, but it would ignite atomised spray.
Just a note on that,if he renews the pump himself?,has he got a FGA and smoke pump to set it back up.
Graeme, your nozzle could be: 0.50/60 deg ES (pressure 110 psi)
or 0.55/80 deg EH (pressure 115 psi) or 0.60/60 ES (pressure 105 psi).
I think your pump pressure is well down if its dribbling!
A new factory pump is set to 150 psi near enough.
The air door should be set at position 9 for starters.
At least, you need a pump pressure gauge and a smoke pump.....!
John :)

Thanks for the info.

Would you start with a new solenoid or just go straight for the pump ??

Is it possible to test the solenoid ?
Personally Graeme I wouldn't do anything without checking the pump pressure - but I do have the gauges, smoke pump and gas analyser. To dive in could cost you a wasted 60 quid or so, and you'd still need to set the pressure. You only replace the pump if it can't reach or maintain the required pressure.
As oil is passing the nozzle, - and you seem sure about this - the pump coil/solenoid isn't really suspect....all this does is to switch the oil on electrically once the burner has finished its 6 second purge stage.
Keep the photocell - MZ770 - completely dark during testing - only allow it to see light if the flame establishes.
John :)
Just some electrode settings:
Spark gap between them = 2.5mm
Distance between electrodes and end of nozzle = 2mm
Distance between nozzle centre and electrode tips = 10mm.
Hope you get it sorted!
Aim for 10.5% CO2 on completion.
John :)
I should have mentioned Graeme - that we are assuming here that the burner motor is healthily spinning at its required RPM...2700 I think it is.
John :)

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