Heating Wiring Centre for 4 Zones

[Ivor Windybottom]

I'm looking at installing a 4-zone heating system. The hot water control and zone valve will be handled separately.

I will be using 4x separate mains wired timer/thermostats plus 4x 2-port zone valves. Including the mains supply and volt-free cable to/from the boiler there will be 10 cables in total.

I'm looking for the best way of wiring this lot up. The standard wiring centres seem to be intended for a lower number of zones, the ones I've seen have 6 cable entry points, although I guess they could be doubled up if really necessary. But they're going to end up pretty stuffed full. I've worked out I can take care of the L connections using 15 terminals. But this would still leave a vast number of neutrals and earths to be commoned, in a pretty small terminal block. I reckon it probably wouldn't all physically fit and/or I'd end up with stupid amounts of wires sharing terminals in the neutral/earth commoning strips.

I've also seen bigger cleverer ones that are intended for underfloor heating. These look like a good solution and would work, but my concern is that they don't use the grey/orange switched contacts from the zone valves, as UFH ones don't have them. I'd prefer to make use of these, to ensure that if the valve doesn't open then the heat pump doesn't switch on.

Here's my rough draft of how I could connect the live/line connections for 4 zones in 15 terminals...

Any comments or better ideas?

 

[JohnD]

In the telecomms world I have seen small cabinets containing DIN rails, with large numbers of connectors, where power supplies were gathered together.

Perhaps you could use one in a large adaptable box.

Or empty out a redundant insulated CU enclosure, which already has bars for neutral and earth connectors.

 

[snb1]

just use a standard honeywell wiring center with 12 terminals.
you can get 3 or 4 (0.75) cables in to each connection point.
use programmable room stats for each zone.

Your heat pump normally needs volt free switching. to do this instead of live to the grey of each 2 port valve you have to connect greys to switching output of air source unit and then the switched demand ( orange will be volt free back to a connection demand on air source unit)

 

[Exedon]

As above standard honeywell box works fine
My own system has 4 zones plus dhw and a normal open valve (X plan)
All easily wired into a standard box.

 

[Ivor Windybottom]

Thanks, I'll order a 16 terminal one for my initial bench test and see how bearable it is.

I was hoping for a max of two cables per terminal but I'm not going to beat myself up about it.

The design is for volt-free switching. The grey and orange wires from the heat pump are connected together as a result of any one or more zone valves being opened. Neither wire is connected to live anywhere.

I'm going to use Heatmiser Neostats to control it. They're nice simple hard-wired timer/thermostats from a company that's been around for years. No batteries. Happy to run cables for them, preferable to relying on wireless. They have the option of adding a Neohub that wirelessly controls each of them, all together from one app. Looks like a good system - simple if you want it, or as complex as you like.

 

[Ivor Windybottom]

I've ordered a Danfoss WC4B. Looks like it will do the job...

I'll remove all the pre-installed links, will ignore their supplied diagram and wire according to my diagram above. I'll print it and stick it to the inside of the lid so it's not a complete mystery in future.

Should be able to squeeze all the N and E wires into their spaces, as it does allow access to each side so 6 terminals for each.

I think the commoning block is lower than the top one, so this will make it neater - can wire them all first, forget about them then do the clever stuff on top. Hopefully there's space to pass cables under the top block and into its top.

Thanks again for all the help, much appreciated.

 

[Ivor Windybottom]

I've revised the wiring diagram to put all the interconnects at the top of the terminal block to suit the wiring centre above...

I've also decided that the live supply will be from the heat pump itself.

I've added a fused switch (5A?) between the heat pump and everything else.

As previously, N and E connections are not shown but will be all commoned using the other terminal blocks.