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You sure your drawing is correct 100% as your boiler requires a perm live and a switch live ?
You sure the red wires arnt perm lives ?
You sure the red wires arnt perm lives ?
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Discuss W-plan pump run on in the Boilers area at Plumbers Forums
That looks correct to me, when you do get there suggest turning both roomstat and cylinderstat to a high setting, when pipe B? to the cylinder coil gets hot about a foot from the diverter valve (and pipe A remains cold, turn roomstat to a low setting (no call) then turn down the cylinderstat, check that pipe A remains cold during boiler overrun.
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Easy way to fix the issue is to get a battery prog room stat eg eph cp4b then move the cylinder satisfied wire and pair it with the prog room stat live and diverter switch eg brown
And then marry up all the switch wires eg boiler switch, pump live, cylinder stat call and prog room stat switch live
And then marry up all the switch wires eg boiler switch, pump live, cylinder stat call and prog room stat switch live
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Easy switch over then just moving some wires etc
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No as your drawing there’s no connection between the room stat and the boiler unless you’ve miss labelled the pump as the boiler switch live ?
I suspect you’ve got your perm and switch lives mixed up
Eg yellow going to the boiler perm live to the wirings centre and the red coming from the boiler / pump switch live etc
Just a quick look but roomstat & cylinder stats are switching the boiler live , they should be switching a SL on the boiler & the boiler should have a permanet Live to allow it to request/do a pump overrun when both the HW & the room stats are both satisfied?.
Not sure this is the exact correct model, but likely similar
Mains from the FCU connects to the boiler at one block.
There is a separate connection block to accommodate a live (out) supply to eg thermostat , a switched live (in) from eg thermostat, a neutral etc etc as below simple example.
Ls is live supply (out). Lr is switched live (control in)
So the Boiler L in the diagram above (post #34 yellow and grey wires) should actually be Lr in the boiler. Hopefully it is like that already.
Mains from the FCU connects to the boiler at one block.
There is a separate connection block to accommodate a live (out) supply to eg thermostat , a switched live (in) from eg thermostat, a neutral etc etc as below simple example.
Ls is live supply (out). Lr is switched live (control in)
So the Boiler L in the diagram above (post #34 yellow and grey wires) should actually be Lr in the boiler. Hopefully it is like that already.
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right.....having gone through all the connections it appears that on the cylinder stat, C & 1 were reversed....the stat is actually marked 1,2,3 rather that C,1,2 which might explain it
I have corrected this and re-drawn the actual installation as it is, I also fitted a new Drayton home battery operated programmable thermostat just to eliminate that
When I tried it yesterday it all seemed OK but was later advised that after the water had been on the rads were still getting hot at the top - suggesting a short run rather than being on all the time
The diverter valve is new and moves and seals OK
I have corrected this and re-drawn the actual installation as it is, I also fitted a new Drayton home battery operated programmable thermostat just to eliminate that
When I tried it yesterday it all seemed OK but was later advised that after the water had been on the rads were still getting hot at the top - suggesting a short run rather than being on all the time
The diverter valve is new and moves and seals OK
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As far as I can see, the only difference the reversal of C and 1 would make, is that the diverter valve would be permanently powered once the cylinder stat is satisfied, irrespective of whether timer is on or off.
Having corrected the C/1 swap, the diverter is no longer powered once the timer is off.
So I hope residual boiler heat won't now be continually pumped around the rads as before, but it seems there's still something of that effect?
Well done for finding that wiring feature!
Having corrected the C/1 swap, the diverter is no longer powered once the timer is off.
So I hope residual boiler heat won't now be continually pumped around the rads as before, but it seems there's still something of that effect?
Well done for finding that wiring feature!
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yes....but if the diverter valve IS / WAS being held open that would explain the residual heat around the rads whilst the pump was over-running......it is only a small house with small rads
I will do another check in case I have missed something but, with it operating as it should, there's no way the residual heat CAN circulate around the rads is there.......unless the pump pressure is keeping the valve open but that is unlikely
"feature" indeed
I will do another check in case I have missed something but, with it operating as it should, there's no way the residual heat CAN circulate around the rads is there.......unless the pump pressure is keeping the valve open but that is unlikely
"feature" indeed
Yes absolutely!
I don't think you've missed anything! Now the diverter should return to hot water position when the programmer/thermostat are off, so hopefully no spurious heating any longer 🏅.I will do another check in case I have missed something but, with it operating as it should, there's no way the residual heat CAN circulate around the rads is there.......unless the pump pressure is keeping the valve open but that is unlikely
"feature" indeed
I was just slightly surprised by the report that rads were still getting hot at the top after water heating, as the diverter surely shouldn't operate if heating isn't called for 🤔
What is the cylinder stat exact make and model?.
Did you do the basic test of feeling pipe A (should be cold/cool) when HW calling and boiler firing and should remain cold/cool on pump overrun.
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I wondered about that...... but I think the printed version is correct....
so C & 1 are connected when it is calling for heat i.e. when the water temp is lower than the set point
when it is satisfied contacts C & 2 will connect as per my diagrams
...it all depends on what they are calling normal.... in my opinion, normal is whan everything is satisfied co normally open would be C & 1
so C & 1 are connected when it is calling for heat i.e. when the water temp is lower than the set point
when it is satisfied contacts C & 2 will connect as per my diagrams
...it all depends on what they are calling normal.... in my opinion, normal is whan everything is satisfied co normally open would be C & 1
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Looks that way to me, so, in the installed stat. 1&2, (where 1 is "C" & 2 is "1") are made when the water temp is < the SP, I would turn up the stat fully and check for continuity between 1&2.
then turn the stat fully down and check for continuity between 1&3.
Also check that pipe A remains cold on the pump overrun, if so, the only other explaination I can think of is some form of reverse circulation.
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Apologies again for the delay in response.......I have been pretty much laid up for 8 weeks with sciatic pain but its finally easing.....
I have just re-checked EVERYTHING
The system IS wired as per my latest diagram in post #38
The cylinder stat operates correctly with continuity between C & 1 calling and C & 2 satisfied
The connector block wiring is all correct as per diagram
The diverter valve doesnt seem to be leaking or bleeding to the rads circuit in its' closed / normal position, it ONLY moves when the roomstat is calling for heat and returns to normal position when the roomstat is satisfied
The pipe from the diverter to the rads ONLY gets hot when it should
The pump overruns for approx 5 minutes during which time, with the roomstat satisfied, no heat (correctly) goes through the rads
With the HW satisfied and the roomstat calling, all the heat goes to the rads
With the roomstat calling, if I turn up the HW stat to calling the diverter valve closes and diverts all the heat to the HW
With the roomstat calling, if I turn it down to satisfied the diverter valve closes to its normal position (HW)
So, as far as I can see it is all physically, mechanically and electrically correct and functioning as it should......time, as they say will tell
but its finally easing.....I have just re-checked EVERYTHING
The system IS wired as per my latest diagram in post #38
The cylinder stat operates correctly with continuity between C & 1 calling and C & 2 satisfied
The connector block wiring is all correct as per diagram
The diverter valve doesnt seem to be leaking or bleeding to the rads circuit in its' closed / normal position, it ONLY moves when the roomstat is calling for heat and returns to normal position when the roomstat is satisfied
The pipe from the diverter to the rads ONLY gets hot when it should
The pump overruns for approx 5 minutes during which time, with the roomstat satisfied, no heat (correctly) goes through the rads
With the HW satisfied and the roomstat calling, all the heat goes to the rads
With the roomstat calling, if I turn up the HW stat to calling the diverter valve closes and diverts all the heat to the HW
With the roomstat calling, if I turn it down to satisfied the diverter valve closes to its normal position (HW)
So, as far as I can see it is all physically, mechanically and electrically correct and functioning as it should......time, as they say will tell
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