Centaurplus C27 to Hive single channel

[Fraser2203]

I have just moved into a new house which has a combi boiler (previously normal with HW cylinder) however the owner retained the Centaurplus C27 clock and just had hot water set to 24/7 to give a live to that circuit. Coming to replace with a hive single Chanel unit and looking for some help. At present it’s wired up for the centaurplus with a neutral to terminal 3 and live to terminal 4 - nothing in 1&2. Would I be right in saying that 3 is HW on and 4 CH on. If so looking for suggestions, is it just a case of bridging the HW on (neutral) into the perm neutral. Assuming neutral and live given colour of sheathings on the wires. Any help much appreciated.

 

[ianmcd]

is it just a case of bridging the HW on (neutral) into the perm neutral

under no circumstances attemp that, what you are calling the HW neutral is a live, never go by the colours of wires in a heating system, they mean nothing, which combi boiler do you have ?

 

[Fraser2203]

under no circumstances attemp that, what you are calling the HW neutral is a live, never go by the colours of wires in a heating system, they mean nothing, which combi boiler do you have ?

You are totally right, I hadn't looked at the wiring diagram properly.

The Boiler is a Grant Vortex Pro External Combi21e, as the name suggests the boiler is outside in a casing so it's a bit more difficult to trace the wiring.

Normally pretty good with DIY electrics but not getting my head around the wiring for the controller, perhaps not aided by it being a dual channel controller hooked up to a single channel system

 

[ericmark]

The first thing is look for instructions and read this seems to be the existing programmer

note it says Centaur Plus is volt free, so it seems the centaur plus is same as Hive single channel and standard one is same as Hive duel channel, so I would be hunting on the actual device to see if there is a diagram. Your picture clearly shows a brown sleeve on the blue wire going to 3 so clearly a line not neutral.

You also need to look at boiler instructions, what I do is use the "find in this page" function and look for "opentherm" and "ebus" and "bus" as key words to find if the boiler should be using an old fashion digital wall thermostat (off/on) or modern modulating analogue thermostat, most boilers can use the old on/off as well, but it will not run as efficiently, Hive does have a work around using on/off only, but also needs the Hive TRV heads to work efficiently which work out expensive.

You also need to look for motorised valves, since the standard method is the programmer supplies the thermostat, and the thermostat supplies the motorised valve and the valve has a micro switch which turns on boiler so boiler can't run until valve is open, if some one has left the old wiring in place you may have a valve working like a relay, you can't assume wired correctly when you have already found a programmer wired as it would have been for a system boiler.

Personally I would not modify until the summer, I would want time to locate parts, and get things fixed and not be in a panic to get heating up and running again fast.

 

[ericmark]

Looking at the instructions page 24 it seems possible the programmer does control the DHW it is not like a gas boiler.

looking at this it seems the programmer may still control DHW even when it is a combi boiler. If it were me I would be considering Hive duel channel, I am not sure if the boiler modulates or uses a mark/space ratio and water store inside the boiler. With a gas boiler common to say 6 kW - 28 kW output, but yours seems to say simply 21 kW output so seems it does not modulate which is expected for oil. There are a series of diagrams I have shown first one, it seems terminals 17 and 18 can be used to turn DHW on/off shown in this diagram with red link.

 

[ianmcd]

oil combis work in different ways from gas combis, the easiest way for you is to take a cable from your existing 2 channel programmer
connect
L to L on hive
N to N on hive
The brown wire in 4 to 3 on hive
Link L and 1 on hive
put the old programmer back on and it will control the HW store only with the existing wiring and the hive will control your heating

 

[Fraser2203]

Thanks for the help, not quite sure I'm understanding it all if I'm honest. The boiler has a small tank inside it I believe but other than that I don't know much about it at all. Might land up contacting the original installer, the boiler is less than 5 years old and installed by a local firm.

 

[Fraser2203]

oil combis work in different ways from gas combis, the easiest way for you is to take a cable from your existing 2 channel programmer
connect
L to L on hive
N to N on hive
The brown wire in 4 to 3 on hive
Link L and 1 on hive
put the old programmer back on and it will control the HW store only with the existing wiring and the hive will control your heating

Hi Ian

Forgive me if I'm being daft here, assuming I could work out if it is a volt free or 240v circuit from the clock to the boiler (guessing would put the multi meter L to either 3 or 4 and the N to the N on the backplate?) and if it is a 240v live circuit then would it work to take the wire from 3 (L to HW on the boiler) and make it permanently live off the live at the L terminal from the spur?

Just for the sake of not having a hive receiver and the old programmer. However, it's in a cupboard out of sight so not the end of the world.

 

[ianmcd]

you could put a link in the boiler and the HW will be hot 24/7 and the hive will control the heating then you can remove the old programmer completely, assuming you dont have any other controls like zone valves or other thermostats, or take the single channel hive back and get a dual channel one.
Volt free means volt free switching , it is so you can use the hive single channel to switch 24V systems, the Hive receiver need an L in L and an N in N to work , these wires have nothing to do with the switching, Hive switches between 1 &3 you are complicating things , the hive is symply a switch nothing else, and intelligent one yes but all it is , is a switch

 

[Fraser2203]

you could put a link in the boiler and the HW will be hot 24/7 and the hive will control the heating then you can remove the old programmer completely, assuming you dont have any other controls like zone valves or other thermostats, or take the single channel hive back and get a dual channel one.
Volt free means volt free switching , it is so you can use the hive single channel to switch 24V systems, the Hive receiver need an L in L and an N in N to work , these wires have nothing to do with the switching, Hive switches between 1 &3 you are complicating things , the hive is symply a switch nothing else, and intelligent one yes but all it is , is a switch

No other controllers/thermostats or zone valves - yeah I get what you are saying, was just wondering on the possibility of making the HW line to the boiler permanently live but would have joined the wires behind the plate so all that was connected on the plate was L, N & 3 and L & 1 bridged like you suggested? Maybe not quite as simple. Only asking as where the boiler is located is a bit of a pain for access but sure it can be done, after all it's been put there in the first place!

 

[ianmcd]

you could put the wire that is in 3 in the existing programmer into the L terminal on the Hive, will do the same thing, you will still have to connect a permanent live though, and the DHW store will be constantly on, be aware though, the terminals on the hive receiver are very tight and you will probably have to use terminal strip to connect everything with only single wires going to the hive

 

[Fraser2203]

you could put the wire that is in 3 in the existing programmer into the L terminal on the Hive, will do the same thing, you will still have to connect a permanent live though, and the DHW store will be constantly on, be aware though, the terminals on the hive receiver are very tight and you will probably have to use terminal strip to connect everything with only single wires going to the hive

Thanks Ian

Might just give the company that installed the system a call and ask them to have a look, pains me paying to do something I'm sure I could figure out but its the piece of mind of the boiler circuit board not going bang I'll pay for!

 

[ianmcd]

where in the country are you ? maybe someone on here could recommend someone to help you out

 

[Fraser2203]

where in the country are you ? maybe someone on here could recommend someone to help you out

Alford, North east Scotland - there is company of local plumbers just up the road and it's their sticker on the boiler for installation so probably give them a shout.
Thanks for all your help

 

[stem]

It would help if we knew what was on the other end of the wires so as to know what they were doing. However, it wouldn't be too difficult to replicate exactly what the C27 is doing now with a single channel Hive. First of all as per @ianmcd

L to L on hive
N to N on hive
The brown wire in 4 to 3 on hive
Link L and 1 on hive

Then if as you say:

had hot water set to 24/7 to give a live to that circuit.

If a permanent live has to be maintained here, then putting the blue wire with the brown sleeve on in the L terminal would replicate the hot water being switched 'on' 24/7. I suspect it might be the way the installer has provided a permanent live to the boiler. But like I said without knowing what's on the other end of it...