Hi I fitted a honeywell y plan system some time back and all has been well...until tonight. I felt the DHW was too hot and turned the cylinder stat down and noticed later that there was no heating. The fused spur unit had blown its 3 amp fuse and did the same to the replacement. When I disconnected the cylider stat (honbeywell L641A) at the wiring centre i was able to get the heating to come on ( obviously with no control over the DHW) All components were new 5 months ago. Can you tell me how to check if the cylider stat has gone faulty or is there likely to be another cause for the fuses blowing. many thanks in advance.
honeywell cylinder stat
- Thread starter mal165
- Start date
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Take a look HERE That stat is just a switch.
C and 1 make a connection when there is a call for heat
C and 2 make a connection when the call for heat is satisfied
you should be able to pass a current through C-1 and C-2 respectively. Whether you do it with wire bulb and battery or multimeter on ohms or continuity is up to you.
My money is that the wiring is wrong. The bit that is hard to get your head round is when the water has reached temperature and the switch goes to C-2 This then makes the grey DV wire live and sends the diverter go to the heating only position.
If a fuse blows theres a direct short circuit. This could be a loose wire and I'd guess something to do with that number 2 wire coming from your cylinder stat. Next stop is your diverter valve and possibly your programmer. Boiler and pump are also suspect. Check that out first and post back
C and 1 make a connection when there is a call for heat
C and 2 make a connection when the call for heat is satisfied
you should be able to pass a current through C-1 and C-2 respectively. Whether you do it with wire bulb and battery or multimeter on ohms or continuity is up to you.
My money is that the wiring is wrong. The bit that is hard to get your head round is when the water has reached temperature and the switch goes to C-2 This then makes the grey DV wire live and sends the diverter go to the heating only position.
If a fuse blows theres a direct short circuit. This could be a loose wire and I'd guess something to do with that number 2 wire coming from your cylinder stat. Next stop is your diverter valve and possibly your programmer. Boiler and pump are also suspect. Check that out first and post back
Hi and thanks for the prompt and helpful reply. You were spot on , silly me had taken ablue wire to the neutral cluster instead of to where it should have bee. All is now well and thanks again for your assitance. This really is a great site. thanks
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