Y-Plan Heating System Integration

[Seb]

Hi, I have decided to hook my current Y-Plan system into Loxone to control both heating and hot water. The current system is a Glowworm Spacesaver 80 boiler (installed late 80's / early 90's I think) controlled by a Honeywell Smartfit [1] system . The Smartfit I know can not be hooked into Loxone, however, by replacing the existing custom control YPlan actuator with a mains one (V4073A1039 [2]), and throwing away the "Smartfit" system, I am left with 240v control of the  boiler, pump and valve.

Attaching a One Wire Temperature Probe [3] to the hot water tank I should then be able to control the whole system with a few relays...

Does anyone have any experience with this sort of setup/config?

Thanks in advance!

[1] http://www.honeywelluk.com/products/Smartfit-Y-Plan/

[2] http://uk.rs-online.com/web/p/products/2463273/

[3] http://shop.loxone.com/enuk/1-wire-temperature-probe.html

[DavidL]

Hello Seb,

This is almost how we do the heating and hot water at home. We use S plan wiring instead, but the principal is still the same.
Instead of a 3 port valve, we use multiple 2 port valves for each "service".
It's worth bearing in mind, a 2 port or 3 port valve will usuall signal the boiler to do its thing once the valves opened. So you can save yourself a relay.

The 1-wire probe in the tank we primarily use as indication of temperature. The switching on and off of the hot water is still controlled by the probe supplied with the tank that the plumber installed, but we use Loxone to control when the 2 port valve is opened dependent on a timer schedule or override toggled in the interface.

The heating is controlled on a room by room basis for us, as each room has its own 1-wire temperature sensor. The upstairs radiators have 230v TRV valves, as do the underfloor heating zones downstairs. The config principal is the same though if you're using 1 central thermostat, or multiple rooms/zones.

If you're planing to just replace your central thermostat, you'd create one timer schedule block and link the 1-wire temperature sensor in to the AI input on an intelligent room controller. You can then set up timings and use the AQ output to trigger your relays for the boiler, pump and valve.

David

[Seb]

Thanks for the config and explanation. Looking at the wiring for the 3 port, there looks to be a central connector block and it's to this I expect the relays to go to.

Will post my updates....

[DavidL]

Yes indeed. The 3 port valve doesn't usually come with a wiring centre, so you'll need to order one of those separately if you don't already have one.

This wiring diagram is quite easy to follow: http://wiki.diyfaq.org.uk/images/1/11/Y-Plan-Wiring.gif

Essentially you've got 5 cores in the cable from the 3 port valve, White, Grey, Orange, Blue and Green/Yellow.
Blue & Green/Yellow will terminate to their respective Neutral and Earth/CPC terminals (2 & 3 if you're using a traditional wiring centre)
White will terminate to your relay to signal when the central heating is required.
Orange will terminate to your relay to signal the boiler and pump to activate (this will also provide power to the cylinder stat if you're using one through the wiring centre - but I don't think you are)
Grey will terminate to your relay to signal the hot water to not be on.

You're then down to programming some logic. I've attached my upstairs heating and hot water config for you to have a look it. It's very simple.
I use memory flags to then compare all rooms to signal the boiler to come on. If you're only using one temperature sensor for the boiler, you could just put it all in one Intelligent Room Controller.

David

[Seb]

Right so I am finally about to do this as am on leave from work and need something to do (and all rads are now actuator controlled)! One question I do have is that the current system cycles the boiler on/off (i think at 15min intervals) and keeps the pump on to cycle the water. This is meant to save gas to help the house get to temp and not massively overshoot.

Should I look to replicate this with Loxone, or just let it fire up the boiler as long as it's needed and it will eventually learn the house?

I'm pretty sure the answer is let loxone be loxone and it will figure it all out, but wanted to ask in case others have seen this?

Best, Seb

[Seb]

Hi, so this is now done and loxone is learning the house. What I ended up doing was installing the Honeywell YPlan kit (1) with the attached wiring. Once that was working I wired in 3 relays into the junction box:

5: CH and bypassed the Honeywell room stat
6: HW on
7: HW off

All my IRC linked into an ITC with the output controlling the pump. I added a schedule for the HW as (for the moment) I still use the Honeywell cylinder stat. With the output from the function block controlling one relay (HW on) and the same output through a NOT logic block controlling the HW off relay.

On the wiring I added a 6amp RCBO to my loxone cabinet, fed that to the 3amp fused switch next to the sysyem, that then came back to the cabinet as the live/neutral feed for the relays that then had 5 core going back to the junction box. This keeps all the electrics for the heating in the cabinet and in regs with the isolating switch in the airing cupboard.

Next is the immersion heater but I can’t get the coupling relay to work using 24v on the switching coil :( I think the relay may be bust or 240v needed on the coil?

Best, Seb

(1) https://www.screwfix.com/p/honeywell-y-plan-7-day-heating-control-pack/91168