wiring room stats for a S plus plan 2 zone system Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[gower2003]

I'm installing a worcesterbosch 24 ri, 3 coil hot water cylinder and solar panels with an s plan plus 2 zone system using horstmann RFT1 wireless programmable thermostats and a honeywell 10 way junction box. . . and
here lies my challenge. Wiring everything other than the stats appears self explanatory but the stats are doing my head in.
I assume the stat for the 2nd heating zone will be a simple 2 wire live common from the junction box terminal 1 and terminal 7 to where? and should it set up for 230v application or volt free
and the room stat for the 1st zone, . . . again do I set it up for 230 volt or volt free application and wires from terminals 2, 4 and 5 go where? you have no idea quite how much this is doing my head in . . . any advice will be welcome

[sparx]

Hi,
If I understand it we can ignore the hot water bit as it's conventional cylinder stat to HW valve, presumably via a timed output from prog/time sw.
So for 2 Heating zones; each rf receiver needs live & neutral to operate, + a link from live to its switch terminal common. (I think term 2).

Add one core from each switch term. (I think term 4) for 'call' which goes back to respective valves 'call' wire.

Valves of course need N,E, to operate. output core from valves switches are commoned to boiler call term.
hope this helps, sorry don't have wiring diagrams to hand as are in van and it's snowing hard out there!!
regards SPARX.

[gower2003]

Hi

Thanks for replying. I'm struggling with the technicalities of this bit.
I'm ok with the rf requirement for live and neutral but do I need to leave the link in place for 230 volt operation for one or both? I was thinking I need it for the 1st zone but not the 2nd

If the stat info had numbers I'd might have got it sussed. I know how to follow diagrams. My challenge is that I've two stat options
1 for 230 v operation: terminals are SL (heat Off), L - Live, SL (heat On), or 2 for volt free operation NO - switched live (volt free), COM - Volt free feed, NC - Normally closed

If I knew whether it was the 1st or 2nd option for each and the correct terminals on the junction box I'd be sorted . . probably.

perhaps when the snow clears . . all the best

Mike

[sparx]

Hi again,
maybe i'm missing something here but can't see why you would have any difference between zones?
As you are using mains valves you can't use 'volt free' option, or where will valve get its signal from?
Leave link from L to (Common)/L . & take output to valve from SL(heat on), same for each circuit.
the volt free option is for systems where you are controlling a signal from a boiler say which might not be at mains voltage, some use 24V controls so you would supply the RF electronics with mains but not link it to the switch change over contacts which are at a different voltage.
hope that makes sense,
regards SPARX

[gower2003]

Hi Sparx

Thanks for your help . . its wired up and ready to go. All being well I won't hear the sound of frying when its turned on.

[gower2003]

Hi Sparx

Finally got the boiler fired up . . . no leaks and it works like a dream . . only one problem, one of my kids has reset the bypass valve pressure and I can't remember what it's supposed to be . . any ideas?

either way thanks again for you help

Mike

[sparx]

Hi Mike, sorry for late reply, been busy!
Bypass needs to be set so only lets by when all valves shut with pump on boiler overrun or if TRV's fitted when all are shut off.
Sorry no fixed setting as each installation differs. I use temp. contact thermometer on pipe by valve, then with smallest zone (usually hot water) only calling for heat, open (wind down) ABV untill temp rises, then back down untill starts to cool.
Not very scientific & needs several rechecks but seems to work,
good luck SPARX

[gower2003]

Hi Sparx

Thanks, all working perfectly. Thanks for your help