You need some advice from an expert on here. I'm just throwing this out as an idea. But normally a mid-position valve is used for CH and HW cylinder using a two channel programmer. I wonder if there is a way to make it work instead with two heating zones. In the usual set up, the signal from the terminal labelled "HW OFF" moves it to the third position.
UFH, combi and seperate CH
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You need some advice from an expert on here. I'm just throwing this out as an idea. But normally a mid-position valve is used for CH and HW cylinder using a two channel programmer. I wonder if there is a way to make it work instead with two heating zones. In the usual set up, the signal from the terminal labelled "HW OFF" moves it to the third position.
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Thanks for this. It could be a way forward. Out of interest do you have any resource I can read for how that is wired up for a mid position with a Ch and HW cylinder setup.
I assume from the photo you attached that for example the mid position valve would always be on open one way I.e. for c heating and then if the timer is on for ch, it would just make boiler live , then hw switch on would make valve to position 2 (grey?) And orange would make it move to mid position?,
https://flameport.com/electric/central_heating/heating_wiring_Y_plan.cs4
This is an amazing resource covering wiring of heating systems. I believe the author actually posts on here as as flameport. My idea is just that. You will need someone far more knowledgeable than me to advise properly.
No, you just connect the two switch lives to the boiler in parallel. Buy an SH-BASE which will include a wireless stat, receiver, and gateway.
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Sounds good. Although I'm not sure how I'm going to achieve this with the 3 port valve without what seems to be the requirement of the timer as now noted from reading the link kindly posted above
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Would you put them in the space to the left of the existing 3 port? In that area on the photo? Or somewhere near the boiler in the other photo?
Yes, where the 3-port is. Remove 3-port, elbow near the floor away from
Like this, essentially
Like this, essentially
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Thanks. That makes sense.
I guess another way I could do this would be to make any signal click on mid position no matter what's requested.
So for instance UFH demands heat, valve is pushed to mid position, then boiler clicks on. Water runs in that case then to both ch and ufh (whichever room ufh requested heat).
And to deal with the rads I have individual upstairs room stats and radiator Trv's, so in theory they are all off until the room needs heat even if UFH has requested?
And vice versa, a trv/room stat can request, mid position clicks, ufh isn't requesting so no flow valves are open on the zones? (I assume that's true)
Does that make sense?
Long winded way, but could be a way for me to avoid plumbing?
What would be the cons of this? Water running around the CH pipes when not needed causing inefficiency?
Oh dear, what were they thinking, using a 3 port like that, they couldn't even fit a decent quality one. Really isn't the way that should have been done TBTH
Appreciate funds are tight but as suggested, it would be so much simpler to get 2x2 ports with a bit of extra 22mm pipe and a couple of fittings. Honestly, anything else along with trying to use the 3 port is just a fudge and end up overcomplicated.
3 ports don't last either due to the way they are stalled using DC power which means the motors burn out that much sooner. To ensure correct functionality the wiring needs to be setup in a specific way with 5 different switching modes - normally via a programmer and with a HW cylinder (HW(B) only, CH (A) only or both (A+B) HW with CH satisfied (B) and CH with HW satisfied (A)) to get the valve to either stall or to rest into the correct position depending on what's required.
Good GIF diagrams here of a Y plan and S plan - http://www.octaveblue.co.uk/c_heating
Appreciate funds are tight but as suggested, it would be so much simpler to get 2x2 ports with a bit of extra 22mm pipe and a couple of fittings. Honestly, anything else along with trying to use the 3 port is just a fudge and end up overcomplicated.
3 ports don't last either due to the way they are stalled using DC power which means the motors burn out that much sooner. To ensure correct functionality the wiring needs to be setup in a specific way with 5 different switching modes - normally via a programmer and with a HW cylinder (HW(B) only, CH (A) only or both (A+B) HW with CH satisfied (B) and CH with HW satisfied (A)) to get the valve to either stall or to rest into the correct position depending on what's required.
Good GIF diagrams here of a Y plan and S plan - http://www.octaveblue.co.uk/c_heating
You wiring is wrong, you don't send perm lives to the 2 ports otherwise they would just stay open all the time.
You don't need to use the boiler output at all either, unless it's being used to power a central wiring centre. The permanent power normally goes to the boiler from the fused connection unit, that would also normally power the wiring centre (the power out from the boiler can do that if needed but that depends on where everything is located)
Permanent lives would be sent from the wiring centre to the grey wires of both 2 ports. When the room stat calls for CH then it's receiver sends a Switched Live (SL) (from the wiring centre) out to the CH 2 port's Live - brown, the motor activates and the valve opens. That hits a microswitch that then sends the perm live on the grey over to the Switched live out - orange. That SL then connects to the boiler (Lr) (via the wiring centre) and turns the boiler on.
With the UFH then an UFH stat would call for heat, the control centre would switch a live in to the boiler switch (from the wiring centre) out to the UFH 2 port live - brown - that 2 port then opens and the microswitch then send the live in - grey - over to the live out - orange and as the same as before, turns the boiler on. The pump switch works the same way as the boiler switch, it would need a live in (from the wiring centre) and then sends a live out that turns on the manifold pump at the same time.
You don't need to use the boiler output at all either, unless it's being used to power a central wiring centre. The permanent power normally goes to the boiler from the fused connection unit, that would also normally power the wiring centre (the power out from the boiler can do that if needed but that depends on where everything is located)
Permanent lives would be sent from the wiring centre to the grey wires of both 2 ports. When the room stat calls for CH then it's receiver sends a Switched Live (SL) (from the wiring centre) out to the CH 2 port's Live - brown, the motor activates and the valve opens. That hits a microswitch that then sends the perm live on the grey over to the Switched live out - orange. That SL then connects to the boiler (Lr) (via the wiring centre) and turns the boiler on.
With the UFH then an UFH stat would call for heat, the control centre would switch a live in to the boiler switch (from the wiring centre) out to the UFH 2 port live - brown - that 2 port then opens and the microswitch then send the live in - grey - over to the live out - orange and as the same as before, turns the boiler on. The pump switch works the same way as the boiler switch, it would need a live in (from the wiring centre) and then sends a live out that turns on the manifold pump at the same time.
There is a solution, but it depends on which way around the 3 port valve has been fitted.
The ports are AB, A, and B.
With no power to the valve it opens AB to B
With power to its white wire it drives fully across and opens AB to A
With power to both grey and white it sits in the middle.
Thus you can have UFH, rads, or UFH and rads.
I can't see which port UFH is connected to, so lets assume port A, thus you will need the following signals: UFH call (for heat), rads call (for heat), and rads OFF or satisfied... rads call to ORANGE wire, rads satisfied or OFF to grey wire, UFH call to white wire.
If UFH is connected to port B then the opposite applies: you will need UFH call, UFH sat or OFF, and Rads call signals....UFH call to ORANGE, UFH sat (or OFF) to grey, and rads call to white.
If you have no OFF or sat signal such as may be the case with an RF programmable roomstat you will have to add a relay with a changeover contact where the CALL signal energises the relay, L(ine) is fed to the common leg of the relay, CALL to its NO contact, and SAT or OFF to its NC contact.
Indicate which port is connected to which service and I'll post a photo of a wiring sketch, but in essence we're making the valve behave as if a hot water cylinder is attached to the B port.
The ports are AB, A, and B.
With no power to the valve it opens AB to B
With power to its white wire it drives fully across and opens AB to A
With power to both grey and white it sits in the middle.
Thus you can have UFH, rads, or UFH and rads.
I can't see which port UFH is connected to, so lets assume port A, thus you will need the following signals: UFH call (for heat), rads call (for heat), and rads OFF or satisfied... rads call to ORANGE wire, rads satisfied or OFF to grey wire, UFH call to white wire.
If UFH is connected to port B then the opposite applies: you will need UFH call, UFH sat or OFF, and Rads call signals....UFH call to ORANGE, UFH sat (or OFF) to grey, and rads call to white.
If you have no OFF or sat signal such as may be the case with an RF programmable roomstat you will have to add a relay with a changeover contact where the CALL signal energises the relay, L(ine) is fed to the common leg of the relay, CALL to its NO contact, and SAT or OFF to its NC contact.
Indicate which port is connected to which service and I'll post a photo of a wiring sketch, but in essence we're making the valve behave as if a hot water cylinder is attached to the B port.
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