What I suggested was just adding the bottom relay.
No need for the other 2 relays.
Last edited:
Wiring centre for central heating & hot water
- Thread starter EngineerJack
- Start date
What I suggested was just adding the bottom relay.
No need for the other 2 relays.
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I see what you mean, the supply for the boiler ought to be taken from the permanent live through the 3 switches (2 zone and a relay) in parallel.
The thermostats ought to be on the control side of the zone switches / relay
Oops- left the thermostats off that drawing completely. Silly me....each should, of course, be between the relevant timeclock and valve (or just the pump for the water)
Oops- left the thermostats off that drawing completely. Silly me....each should, of course, be between the relevant timeclock and valve (or just the pump for the water).
And yes, see what you mean about the relays- so busy avoiding the loop from the boiler I missed that one. Drawing amended.....
There's another amend to make depending on how the pump overrun works at the moment.
And another option- with the relays buffering, there is no back linking to the motor of the valve via the valve microswitch. There is an argument that says the supply to the microswitch should be direct rather than via the timeclock/thermostat. Problem with that is if the motorised valve is manually opened then the pump will run for ever... if this is desirable (and in some circumstances it may be) then do it, if there were no relays involved then you'd have to do it (otherwise as posted above when more than 1 zone was calling they would latch on until all zones were off on the timeclocks)
And yes, see what you mean about the relays- so busy avoiding the loop from the boiler I missed that one. Drawing amended.....
There's another amend to make depending on how the pump overrun works at the moment.
And another option- with the relays buffering, there is no back linking to the motor of the valve via the valve microswitch. There is an argument that says the supply to the microswitch should be direct rather than via the timeclock/thermostat. Problem with that is if the motorised valve is manually opened then the pump will run for ever... if this is desirable (and in some circumstances it may be) then do it, if there were no relays involved then you'd have to do it (otherwise as posted above when more than 1 zone was calling they would latch on until all zones were off on the timeclocks)
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When the manual lever is selected on a valve it doesn't leave the switch closed.
The valve is only partly opened for bleeding/draining.
The valve is only partly opened for bleeding/draining.
It does now on the most recent Honeywell 2 port ones!
It does on every valve I've worked with apart from the British Gas branded ones on my parents system. Not triggering the switch was a bit of a PITA when the programmer failed at my parents - had to use a clamp to hold the lever over all the way to work a switch to get the heating to run.
But back to the OP's issue - I'd have thought the best thing to do would be to trace out how the current system is wired. Armed with that information, someone can probably suggest simple alterations to fix the problem without a rip and replace.
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