Honeywell St9100a to dual channel Hive

[robrnr]

Hi i currently have a Honeywell St9100a programmer which i intend to swap for a dual channel hive. i have an S plan system with hot water tank. The hot water has a pump in the airing cupboard. i have wired it up the same. N L 1 3 and 4. With a loop between L and 1. Boiler is not firing up. Any advice welcome

 

[cross thread]

Have you a old room stat? I so have you linked it out

 

[ian1182]

The link between L & 1 is only required on a Combi that uses 240V switching and then only with the single channel Hive.

You said it's a 2-channel Hive but a Honeywell ST9100A is a single channel controller. What looks after your hot water? What sort of boiler do you have?

The picture of your old wiring looks unusual. terminal #3 has a connection but the ST9100A diagram shows nothing should be there.

However based on the old wiring, it looks like you have a Combi and the connections were
L & N (power)
Earth
#1 link across from L
#3 black core parked here but not used
#4 central heating "on"

For an S-Plan system using a 2-channel hive you should connect L, N for power , 3 for hot-water and 4 for Central heating. The earth tether is a useful spot to connect the Yellow/Green core. 1 & 2 should be left unused. But I have doubts you have an S-Plan system.

As for the roomstat, as cross thread indicates, link it out. But the easiest at this stage is just turn the roomstat up to max. When your system is working you can then link it out properly.

 

[robrnr]

Thermostat was wireless, but has a very old thermostat that is still on the wall

 

[ian1182]

If your prior thermostat was wireless you should have a receiver unit which needs to be linked out then. Otherwise you have an "open circuit" and the boiler will not fire up.

Can you outline all the components previously being used.

 

[robrnr]

Thanks for the replys. i have a worcester bosch 30 cdi. This is wired to a fused spur and then to the honeywell receiver as shown in pics. There is a seperate hot water tank which the boiler heats up and a tank in the loft, plus a pump in airing cupboard for the hot water. There are two valves connected to the tank. Hence why i presume is an s plan gravity fed system that requires a dual channel hive

 

[Deleted member 267285]

If you have an s plan and only one programmer for the hot water, then you need something to link to the Hive. Probably better installing Hive in the cupboard where the motorised valves and pump are and should be a wiring center, decommission existing connections and make new ones for Hive in there.

 

[ian1182]

If I understand correctly. At the moment you have a ST9100A managing the hot water schedule and a programmable roomstat handling the heating. You wish to replace both by a 2-channel Hive.

As CBW indicates best to place for the Hive near the wiring centre as that makes any cabling much easier.

At this stage it's probably best to map out the cabling connections in the wiring centre and match that up to the expected arrangement as per

S Plan central heating system

S-plan central heating system operation and wiring diagram

flameport.com

If you have some pictures of the wiring centre post them here to allow assistance.

 

[robrnr]

The st9100a is set to always on. i presumed this did the heating and hot water. The thermostat just controls the heating. The wireless thermosat controls the st9100a so i thought all the wiring would be just there. If its more complicated thanthat its beyond me im afraid

 

[ian1182]

Currently you have a single channel controller which if it's permanently on is effectively bypassed. I guess that means your HW is also always on and just controlled by the tank thermostat. Your heating is then managed by the room stat. To swap that out for a 2-channel Hive and provide full control would certainly call for some cabling effort at the wiring centre.

Do you have a picture of your thermostat receiver? You said the stat is wireless, so that implies there is a second box (i.e. receiver). It should be possible in that case to swap out the receiver unit to give you smart heating. You could then leave the existing ST9100A as "always on" or subsequently fully bypass it.

It may be possible to retain the 2-channel Hive and run it looking after a single channel (heating) with the hot water side unused. Or equally swap the 2-channel Hive for a single channel model. Depends on what's at the receiver. All is not lost just yet.

 

[robrnr]

Thanks again Ian. This is the room thermostat. i don't think i have another receiver, i think its just the st9100. Sounds like i may need the single channel and set the hw to always on

 

[ian1182]

I think you should have one of these or similar

Pardon our interruption...

It may be in the same place as the hot water tank and wiring centre.

Otherwise I wonder how the wireless part communicates

 

[robrnr]

Found the receiver in the airing cupboard, so makes sense now. Just deciding now wether to stick with the hive or go with a honeywell evo and then i won't need any wiring

 

[ian1182]

Sounds like it should be fairly straightforward to implement then. Hopefully a simple swap of Honeywell receiver. I think you may find Evo & Hive use a very similar (if not the same) mounting back plate.