Worcester Greenstar Heatslave 25/32 oil burner not firing

10 Jan 2013
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United Kingdom
I am a plumber (but not a boiler engineer) and have installed a Greenstar Heatslave 25/32 oil fired boiler in a property in France. After a couple of lockouts due to air in the oil (dual pipe) feed, the boiler worked fine for about 15 mins and had just started to heat the pipes when it stopped firing. After turning on the direct hot water it fired again for a few minutes and stopped again. The pump and diverter valve are working fine and none of the reset switches need resetting. The fascia mounted programmer is functioning fine and the DHW and CH thermostats seem to be working (switching as they are turned up and down) but there is no power to the burner line from the control board. The burner/oil pump do not make any attempt to start when asked. As the burner does not try to start, I am unable to see if the oil pump needs bleeding. In my un-expert opinion, I am assuming there is a sensor problem preventing any power to be sent to the burner but have no idea where to start. I don't think this boiler is sold in France and assume a French engineer is going to struggle. Any advice would be immensely appreciated.

Many thanks,

Jeff Gascoyne.
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Which reset switches have you tried. Apart from the burner, there are overheat and flue thermostats that can cut the power to the burner. Methodical following of the circuitry with a multimeter should sort out your problems.
Am I correct in saying that there are 3 manually reset stats on these.....?
1) High limit stat on the top of the combustion chamber top, close to the pump
2) Flue overheat stat (behind the burner)
3) Water temperature overheat (top left inside the door, push upwards)

And definitely a fuse on the pcb (I think the Heatslave uses a 3.15A slow blow) :confused:
John :)
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Thanks guys,

It was a the CH return valve not being fully open causing the overheat cut out (silly mistake). Apparently holding down the reset button for 60 seconds then over rides this cut out.

Many thanks for your input, much appreciated! :D

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