Help with central heating programmer wiring

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I've moved into a house which seems to have a very complicated heating setup, which I'd like to replace with a regular 7 day programmer / thermostat (specifically a Honeywell T3R).

The house has a boiler, hot water cylinder (with thermostat), pump on the hot water cylinder and a cold water tank in the loft.

On the programmer side, at the moment there's a 3 way changeover switch (for "normal", "away", and "off"), two central heating / hot water programmers ("normal" and "away") and a GSM remote control.
There's no thermostat that I can see anywhere, which is the main driver for junking it.

0UIZPzm.jpg


I think all the connections I need are in the 1 gang box above the FCU and I can just chuck the board with all it's relays etc.

What's throwing me is the wiring:

SheRv6J.jpg


1, 2, 3 - Live, Neutral, Earth, easy
4, 5, 6 - Don't know but not connected to the current controller so can leave alone.
7, 8, 9 - these are what the current programmers are controlling. One is labelled "H/W on", one "C/H on" but the last says "H/W" (I think - it's hard to read). It's obvious where to wire "H/W on" & "C/H on", but I've no idea what the "H/W" would do - I wasn't expecting a third cable. And although all three go into the current wiring board, it's not obvious where they go (they go via some kind of controller) but each programmer only has two connections (beside power, obviously).
10 - No idea, either, but again not connected.
 
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What type of valves (2 x 2 port or a 3 port valve) do you have ?
 

CBW

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A photo of the big control panel underneath the boiler might be relevant as well.
 
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Looks quite an interesting set up somebody's put together, shame they didn't leave any details on how it worked in use.
 
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What type of valves (2 x 2 port or a 3 port valve) do you have ?

3 port valve

v5DY3iX.jpg

Scrap the lot and start again.
Far quicker than attempting to unravel someone else's undocumented mess.
Looks quite an interesting set up somebody's put together, shame they didn't leave any details on how it worked in use.
There is documentation, reams of it, but most of it is useless and the wiring diagrams I have I'm not confident represent what's actually installed (...or are even for this house...).







I think "H/W Off" makes sense for the extra cable, I'll test it with a multimeter to understand what's going on.
What threw me is that at the controllers there's no third cable, but looking at one of the wiring diagrams it looks like it's been wired up to "create" the H/W off from the H/W / C/H outputs of the existing programmers.
I also think I've bought the wrong programmer/thermostat as it doesn't have a H/W off connector...
 
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You can use the T3R, but that's only for the heating. You will need a timer/programmer for the hot water as well, that will have the HW Off terminal.

Wiring is a standard Y plan.
 

DP

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Looking at the timer backplate, seems there might be an issue of spurious boiler operation hence capacitors fitted in the backplate. Better to digest the info in the literature and then make alterations.

A bit OTT but some of it might have been relevant, other might be to make the system run economically like recovery of residual heat post boiler run
 
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Thanks for the help everyone - once I got my head around y-plan it makes sense.

I wanted a single unit that controlled everything, and the Honeywell programmer I bought was the wrong tool for the job.

I struggled to find a single wireless thermostat / programmer unit that would do y-plan - it turned out the cheapest option was a smart unit.

Replace the lot with a Nest.

W6kzOSJ.jpg
 
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