Worcester Greenstar Heatslave 12/18 oil boiler not firing up

3 Jul 2021
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United Kingdom
Paul Langston
Hi All,

I have a Worcester Greenstar Heatslave 12/18 oil boiler which stopped heating domestic hot water or central heating hot water today. The pump is running when the controller is set to either HW or CH but the boiler isn't firing up. When it first happened this morning the pump was red hot, couldn't touch it and have had this problem before, about 6 months ago. Then it cost us about £600! The engineer changed the pump, etc and then changed the DHW thermostat and that seemed to resolve it. I don't really want to call them out again (another £600 later!) when I am comfortable is changing the stats and thermocouples (if that is the problem) but having looking inside the control unit there appears to be at least thermostatic units (DHW and CH, attached to control knobs and one, with a thermocouple but no control knob - see photo on link below).

So my question/s:

Is it likely to be one of thermostats?
If so which one?
If not, any ideas?




Read more: https://www.diynot.com/diy/threads/worcester-heatslave-12-18-oil-boiler.573901/#ixzz6zcp3BmLd
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