Worcester heatslave 25/32 Hot lockout

[Burnerman]

Personally I've never had any issues with those either....as far as I know its to stop dribble when the burner shuts down, and I believe some people leave it out altogether. I wouldn't have thought it could be the cause, but there again, what do I know.....
I believe this has been discussed before, somewhere!
John

 

[Aeroengineer]

Thanks for that John. will post on the solution when we get there, I appreciate your assessed input . Regards Adam.

 

[Aeroengineer]

Its been a few weeks now and I can report all is now fixed with the troublesome Boiler!. Having looked at all aspects of this have deduced the following. Measured the pump pressure was found to be ok but with quite a swing in max and min pressure should have been no more that 15% from preset which was 10bar 130psi. Could not really find a fault with the pump other than age approx. 10yrs. Having now decided to replace the pump to discover a similar pressure swing but not quite so bad as before. So now the head scratching...... boiler fault was similar but not quite the same would now run some considerable time before shutting down as normal and then when restarting the next day was surging having delayed ignition. So back to the drawing board. It was mentioned previously about the check valve in the nozzle support tube but neither of us had heard of or experienced an issue with this so you automatically discount it as being part of the problem so as john said previously I removed it........ ha stable ignition it changed the whole feel of the boiler. The issue and my supposition. The check valve seal had failed causing the valve to oscillate causing the pressure the drop off and to allow air to be drawn back into the nozzle when the boiler had cooled causing an airlock in the nozzle tube assembly which it could not clear causing the erratic ignition and unstable burning of the oil as the mist pattern was all over the place. New valve now fitted and all's well, been operating now for the last 4 weeks not so much as a hiccup ( Touch Wood!) can we take something from this .....maybe hope it helps others I know it did my head in for a while! and thanks to all that contributed to the thread it was appreciated.

 

[Burnerman]

Many thanks for the update - we are pleased to hear that its behaving itself!
Regarding the pressure swing....does the gauge reading vary as the burner is running? Thats a new one on me!
John

 

[Aeroengineer]

Many thanks for the update - we are pleased to hear that its behaving itself!
Regarding the pressure swing....does the gauge reading vary as the burner is running? Thats a new one on me!
John

That was the strange thing John... it only had that pressure fluctuation when the problem arose i.e. on a fresh start in the morning. I'm guessing that the valve chatter was making the pump pressure regulator unstable and it was starting to oscillate which then would amplify the overall problem.

Another pointer: If I was to fill the nozzle support tube, then fit the valve and top up again and fit the nozzle the problem did not exist. That is until the next day when I assume the fuel oil was syphoning out of the nozzle overnight, causing the air lock on restart. So take from that what you will for me all pointed to the valve.

No way was this thing going to get the better of me ! Lol

 

[Burnerman]

Interesting, and completely logical thoughts!
I'd be interested to hear others thoughts on this one.....if that valve is to prevent back flow / dribble or whatever, it seems unlikely that it could resist 125 psi oil pressure!
John