Drayton Wiser replacing ST9100C1006 CM927 CM907 BDR91 Megaflo

[Hounds]

Hi, please can someone help me. I have tried for days but cannot do it.

Currently I have 2 zones and hot water run off a conventional boiler.
The sytem works perfectly with my ST9100C1006 and the 2 thermostats (CM927, and CM907).
I am looking to replace all with Drayton Wiser, mainly for smart TRVs. I opted for the 3 channels as I have the 2 heating circuits.

There appears to be 4 sets of cables.
The cables on the left appear to be live (240v).

In the ST9100C1006, all the Live cables go in Live, all the neutrals in Neutral (including one grey cable with blue sleeve), and a black cable with live sleeve is in the end port marked "Neutral ON". There is also a jumper cable between Live and 1.

Cable layout needed for Drayton Wiser 3 channel

Thanks in advance.

 

[ericmark]

So you want to replace a single relay with three relays, it seems from what you show there is no DHW control from the old ST9100C1006 it likely turns on the supply to both wall thermostats which in turn turn on the motorised valves which in turn turn on the boiler.

So your missing the wire from the second wall thermostat, which is not really required anyway.

Back to basic there are two ways to zone the heating system, hard wired motorised valves, and wireless motorised valves the latter normally called TRV's. Very rare will you use both, my home is one of the rare ones, as there is a flat under the main house rarely used in winter so whole of flat turned off by one motorised valve. But that's not normal.

I would have used a single channel programmer/thermostat with a combi boiler, or a twin where using an external store for DHW.

I see no way from what is shown to control DHW and neither does there seem to be the option of controlling two central heating zones.

 

[Hounds]

So you want to replace a single relay with three relays, it seems from what you show there is no DHW control from the old ST9100C1006 it likely turns on the supply to both wall thermostats which in turn turn on the motorised valves which in turn turn on the boiler.

So your missing the wire from the second wall thermostat, which is not really required anyway.

Back to basic there are two ways to zone the heating system, hard wired motorised valves, and wireless motorised valves the latter normally called TRV's. Very rare will you use both, my home is one of the rare ones, as there is a flat under the main house rarely used in winter so whole of flat turned off by one motorised valve. But that's not normal.

I would have used a single channel programmer/thermostat with a combi boiler, or a twin where using an external store for DHW.

I see no way from what is shown to control DHW and neither does there seem to be the option of controlling two central heating zones.

Thank you for your reply.
Correct, I believe when I was running tests, both thermostats are controlled by 1 cable.
So what would I need based on my config? To enable smart TRVs and control hot water (ideally wirelessly)?

 

[CBW]

What is currently controlling the hot water on and off timed periods?

 

[Hounds]

What is currently controlling the hot water on and off timed periods?

The device I am changing does; the ST9100C1006, via "programme" or "extra hour".

 

[Hounds]

My second zone radiators are controlled by a BDR91(and the CM927).

 

[CBW]

Ok, so which one does the heating? you should have a dual channel or x2 single channel.

 

[Hounds]

Ok, so which one does the heating? you should have a dual channel or x2 single channel.

The CM907 does downstairs (far away from the ST9100C1006), and the CM927 (wirelessly linked to the BDR91) upstairs.
Both the CM927 and CM907 are independent of each other, and are both programmable.

So i need a dual channel (hot water + 1 heating) in place of ST9100C1006. Meaning both the CM907 and CM927 become obsolute after smart TRVs are installed?

 

[CBW]

Sorry, I wasn’t sure if you had wireless programmable thermostat’s. If all the wiring for them is in that photo where all the lives are, then it’s just a case of figuring out which wires you need and don’t need. The Wiser will take care of the switching, which are your a and b on the bdr91, so you can probably lose a few of the permanent live and neutrals.

Figure out which is the main permanent live and neutral, and then just figure out your switching for the heating and hot water and you should be ok with the Wiser 3 channel.

 

[ericmark]

Before looking further, my question is what controls the DHW? Have you got some cylinder with hot water in, as to date seen nothing to show how DHW is controlled.

 

[Hounds]

Before looking further, my question is what controls the DHW? Have you got some cylinder with hot water in, as to date seen nothing to show how DHW is controlled.

We have a megaflow, run by the ST9100C1006 (that I am looking to make smart)

 

[ericmark]

That picture shows all three motorised valves and it would seem that's where the Wiser unit should be fitted.

 

[Hounds]

That picture shows all three motorised valves and it would seem that's where the Wiser unit should be fitted.

Thank you so much - this way seems easier, as the cable layout inside the Megaflo is a lot clearer.

So to confirm, the "motorised valves" are those the "honeywell metal boxes" (makes sense as the timers are Honeywell, also there being 3 as its a 2 way CH system + HW).

I need a 2 way Wiser (not my 3 way), and connect the HW and just 1 CH + add my smart TRVs to all rads.
The cabling for the Wiser (when I get it) will be links from L+N + presumably 2 cables, HW and just 1 of 2 CH).

Do numbers 2 / 4 in the Wiser diagram need cables?

If that is correct, can I then remove all of my Honeywell equipment?
Thanks.

 

[Hounds]

My 2 way Wiser arrived, but somethings wrong, the gas hot water boiler isnt igniting - but is instead (I believe) powering on the immersion heater.

I obtained the cables direct from my Megaflo. I have not removed the megaflo cables, but instead added a cable to the top part of the corresponding terminal strip.

I connected both N + L to the Wiser, as well as the red circled wire (which is hot water - when this is disconnected my gas boiler will not ignite) to No.1 of the Wiser.

I have not added any heating cables yet, as I wanted to do 1 step at a time. Incidentally the actual water timer (ST9100C1006) is in another room.

Any help would be appreciated. Thanks.