Wiring a new hive receiver. Confused.

[Robshelf]

Hi all,
As you’ve probably guessed from the title I have another Hive wiring question. I’ve scoured back through old threads but not found a match so figured I’d ask.
My current Danfoss 103 programmer has been making some funny noises so I took advantage of Black Friday to pick up a Hive thermostat, thinking it would be a case of one in, one out. It hasn’t panned out like that.
The danfoss connects to a worcester Bosch green star boiler. There’s a thermostat of unknown make on the stairs too. All controlling the ch and hw.
I’ve attached a pic of the current danfoss wiring, the 4 core cable is coming from the mains. The solitary “live” cable heads off to the boiler. My initial assumption was that the thermostat fed in here too, clearly it doesn’t, my next job when I get home later is to figure out where that’s going but I wanted to see if anyone had suggestions on wiring the hive receiver.
Cheers

 

[stem]

There's not a lot to go on there, and some odd information too.

The danfoss connects to a worcester Bosch green star boiler.

That's a bit like saying my car is a Ford. There are lots of different Greenstars. Can you be a bit more specific? Is it a combi boiler? or a heat only boiler with a hot water cylinder somewhere?

There’s a thermostat of unknown make on the stairs too. All controlling the ch and hw.

The room thermostat is also controlling the hot water??? Really!

The Danfoss 103 is a single channel timeswitch, it doesn't have the facility to provide control of the hot water and central heating separately, so the Hive is not really compatible with it. Unless you do have a combi boiler and don't need any hot water control, in which case the single channel Hive could be used.

 

[Robshelf]

There's not a lot to go on there, and some odd information too.

That's a bit like saying my car is a Ford. There are lots of different Greenstars. Can you be a bit more specific? Is it a combi boiler? or a heat only boiler with a hot water cylinder somewhere?


The room thermostat is also controlling the hot water??? Really!

Apologies.

Would it be a Greenstar RI? Its a condesing boiler. It heats both as and when the danfoss tells it to come on with the thermostat dictating whether or not the radiators are on. The hot water is a gravity fed system.

I meant that to read that the whole lot is controlling the ch and hw rather than the thermostat alone.

The Danfoss 103 is a single channel timeswitch, it doesn't have the facility to provide control of the hot water and central heating separately, so the Hive is not really compatible with it. Unless you do have a combi boiler and don't need any hot water control, in which case the single channel Hive could be used.

Thats what I feared after looking at things more closely. Glad I kept the shipping box then.

 

[stem]

OK thanks for the clarification, that makes more sense.

So, if by:

The hot water is a gravity fed system.

You mean that the hot water is circulated around the boiler and hot water cylinder by gravity circulation (in that it's not pumped). Then you can use the Dual Channel version of the Hive, as it does have the facility to be used with the old type of gravity systems, as per page 13 of the manual below:

...but it would require rewiring.

 

[ianmcd]

can you have CH on its own ? or do you have to have CH&HW on at the same time but can have HW on its own

 

[stem]

The OP has a Danfoss 103....



...which only has one channel, so they will both be 'on' together.

Whether they have to be like this because of the restrictions of the plumbing, or just because they share the same Danfoss timeswitch, I suppose is the issue. Personally I feel it is most likely the former, but you never know stranger things have happened.....but not many

 

[Robshelf]

OK thanks for the clarification, that makes more sense.

So, if by:

You mean that the hot water is circulated around the boiler and hot water cylinder by gravity circulation (in that it's not pumped).

There is a pump in the mix but it matches the gravity fed setup here http://www.handymanknowhow.co.uk/plumbing/howheatingworks.htm

The hot water cylinder is attached to the pipework in the pictures. The switch at the top is for the backup Immersion heater. I confess to not chasing the thermostat wiring yesterday but the new assumption is it comes into one of the boxes at the bottom.

...but it would require rewiring.

When you say rewiring do you mean "get a professional its a huge job" or the existing wiring needs tweaking connect cable A to 1 rather than 3?

Thanks for the help.

 

[Robshelf]

can you have CH on its own ? or do you have to have CH&HW on at the same time but can have HW on its own

The last one. Can have hw but no ch but not ch but no hw.

 

[stem]

I guess then by that, you mean no heating when the room thermostat switches off, but the 103 is still on so heating the hot water. The interesting thing though is that your photo shows a two port motorised valve. I can't see what the pipes are connected to, but I don't suppose there is another one somewhere else is there?

 

[Robshelf]

I guess then by that, you mean no heating when the room thermostat switches off, but the 103 is still on so heating the hot water.

Correct. The only difference between hw only and hw and ch is what the thermostat is set to.