Hive Thermostat - using the Hot Water circuit

[austin99]

I have a Greenstar 36CDi combi boiler with a Hive (single channel) thermostat. There are two circuits, downstairs & upstairs - the Hive controls downstairs and it works correctly.

We don't use the heating that much upstairs, maybe boost it for 30 mins every now and then.

I presume I could control the upstairs heating circuit using the Hot Water control if I switched my single channel Hive receiver for a dual channel one? It's just a switch after all... Upgrading to multizone Hive seems excessive and unnecessary. Thoughts?

 

[stem]

Each Hive receiver can only communicate with one Hive thermostat. In the case of the dual version, it would only be the central heating channel that the thermostat controls. The hot water channel of the dual channel version does not have temperature control (this is achieved by the hot water cylinder thermostat) it only provides on / off time control for the hot water.

The closest you could get is to use the Central Heating channel with a Hive thermostat, and for the second zone connect the hot water channel to a wired room thermostat and use the Hive to turn it on and off. No thermostatic control would be available via the Hive though.

 

[austin99]

for the second zone connect the hot water channel to a wired room thermostat and use the Hive to turn it on and off. No thermostatic control would be available.

Yes, that is exactly what I was thinking. Not ideal (or standard practice) to not have thermostatic control, but since the 30 min or 60 min boost is used it won't be a problem.

 

[stem]

You will have thermostatic control provided by the wired room thermostat, you just wouldn't be able to control it from the Hive.

 

[austin99]

Umm, I'm slightly confused...

Before I put in a Hive, I had a EPH timer. Wires #1, #2, #5 (downstairs heating channel) and #7 (upstairs heating channel) were the only ones used.

After putting in a Hive Single channel receiver, I had connected EPH #5 to Hive #3. I can now control my downstairs heating with the Hive Thermostat - all good.

What I'm thinking of doing is swapping in a Hive Dual channel receiver and connecting EPH #5 to Hive #4 and EPH #7 to Hive #3.
With this configuration I'm hoping to continue to control the downstairs heating with the Hive thermostat (as I currently am) and to also be able to control upstairs heating by using the "Hot Water" boost function on the Hive (but without thermostatic control...which isn't a problem for the manner in which we heat upstairs in this house). Do you think there's any reason why this wouldn't work ok? Thanks

 

[ianmcd]

Could be done that way, but a bit Heath Robinson to be honest, why not just do it correctly, and get total control over both zones

 

[austin99]

Could be done that way, but a bit Heath Robinson to be honest, why not just do it correctly, and get total control over both zones

Agreed that it's a bit hacky but I don't really want to buy another Hive thermostat + receiver when the functionality already exists in the Dual channel version of what I have already.

 

[ianmcd]

Agreed that it's a bit hacky but I don't really want to buy another Hive thermostat + receiver when the functionality already exists in the Dual channel version of what I have already.

Its your house , you can do what you want , it will work, just not what it is designed to do, dont sell the house with it connected up like that though

 

[ericmark]

I suppose in a way it would work, however Hive is designed to work with TRV heads where they send a signal to turn on boiler, this would turn on boiler but not open the right motorised valve.

I must admit I read these pages and ask why have both motorised valves and TRV, they both are doing the same thing so it seems to be duplicating.

 

[ianmcd]

however Hive is designed to work with TRV heads where they send a signal to turn on boiler, this would turn on boiler but not open the right motorised valve.

Total rubbish, the hive opens the corrosponding motorised valve, the valve tells the boiler to come on

 

[ericmark]

I far I am am lead to understand the TRV head sends a "demand for heat" to the wall thermostat, so if either the wall thermostat is too cool or the TRV is too cool, then the thermostat will turn on the motorised valve, which in turn turns on the boiler.

The motorised valve acts like a relay so either valve can fire the boiler, but no back feed.

I see the whole idea of turning off bedrooms during the day, when it does not include bathroom and no bedroom is used for other than sleeping, but kids do home work in bedrooms, and when kids leave, the rooms become offices, craft rooms, etc.

So whole idea is flawed.

A programmable TRV head costs around £10 and a motorised valve around £40 so 8 x TRV heads = 2 x motorised valves, so there is simply no point.

But it seems people interprete the law to say must have motorised valve but the TRV is a motorised valve.

 

[ianmcd]

A programmable TRV head costs around £10

Not for hive it doesnt they can be baught as an upgrade but are around the £55 mark each