Smart thermostats / Hive

[gc100]

Hi,

 

I always envisaged that with my build I would be installing a smart thermostat such as Hive/Nest . We are planning to install an Ecodan Ultraquiet unit in our house but it seems that for example the Hive unit can only control the heating element at best.

 

I"m wondering if anyone has gone down this route and how they got on with their ASHP and smart(er) thermostats?

 

Thanks

[ProDave]

What is the problem?  Why can't a Hive thermostat control an ASHP?  No different to it controlling a boiler.

[gc100]

21 minutes ago, ProDave said:

What is the problem?  Why can't a Hive thermostat control an ASHP?  No different to it controlling a boiler.

 

As I understand you cannot control the hot water only the room temps. I don't even know if they are compatible - hence I was wondering if anyone had any experience. Searching online in regards to ASHP doesn't give me much.

[PeterW]

Hive only plays nicely with S-Plan systems as it is used to having the zone valve to control when doing both heating and hot water. 
 

AIUI - the Ecodan controller needs different signals to control a higher temperature for water.  To be honest I would let it do that as I can’t really think of a use case where you would want to control the hot water from your phone / iPad / tablet as you want it to be either “on” or “off”. If you’re on E7 too, you will want to be optimising the night usage anyway. 

[ProDave]

I have only worked on one Ecodan system (not the quiet version) and it had a simple volt free input contact to "call for heat" from the heating system.

 

If a Hive can't do that, I would look for a different thermostat system.

[PeterW]

3 minutes ago, ProDave said:

I have only worked on one Ecodan system (not the quiet version) and it had a simple volt free input contact to "call for heat" from the heating system.

 

If a Hive can't do that, I would look for a different thermostat system.

It can - but the Ecodan controller for hot water is a different beast. 

[ProDave]

37 minutes ago, PeterW said:

It can - but the Ecodan controller for hot water is a different beast. 

That was my finding for my LG ASHP. The only "as designed" way to control the HW heating was the supplied controller.  I had to get inventive to create the facility to turn the hot water on and off from an external demand.

[SCottyH]

Hey ProDave,

I appreciate this is an old post but I've just had an LG Therma V ASHP installed and wondered what your inventive way of getting the hot water on demand with Hive was?

Hoping I can apply it to mine rather than run hot water all day when it isn't needed.

[ProDave]

43 minutes ago, SCottyH said:

Hey ProDave,

I appreciate this is an old post but I've just had an LG Therma V ASHP installed and wondered what your inventive way of getting the hot water on demand with Hive was?

Hoping I can apply it to mine rather than run hot water all day when it isn't needed.

I don't use a hive, just an ordinary central heating programmer, but the same principle should apply.

 

The ASHP senses water temperature with a temperature probe which is supplied with the unit, this is just a thermistor.  So I uses a single pole changeover relay.  The normally closed contact puts a fixed value resistor in place of the thermistor.  the normally open contact puts the thermistor into circuit.  the relay has a 240V coil and is switched from the programmer.

 

So when the programmer says "hot water off" the fixed resistor is in circuit in place og the thermistor which makes the ASHP think the water is at 85 degrees and hence hot water is satisfied and never turns on.  When the programmer turns on the thermistor is switched into circuit and it reads the true water temperature and turns on when hot water is needed.

[Puff]

No idea what ProDave said in English but I have a Hive controlling the heating in my place but the HW bit controls the immersion heater. Not perfect but then my house used to be empty for weeks at a time and it was enough to get the HW hot for when I returned home.