Using two 2 channel Hive receivers in one system to control immersion heater

[Brian McHugh]

Is there any way to use two 2-channel Hive receivers in the same system using the Hot Water circuit on the second receiver to control an immersion heater via a 40A relay?

 

[polesapart]

Must it be Hive?

I'm sure there are cheaper internet-enabled switches to operate your relay.

 

[ericmark]

A motorised valve is a relay, so yes, the relay replaced the motorised valve, but why?

 

[CountryFan]

A motorised valve is a relay, so yes, the relay replaced the motorised valve, but why?

You do realise the question is about an immersion heater?

 

[ericmark]

You do realise the question is about an immersion heater?

This is why I said "but why" I think it is far easier to fit a timer direct to the immersion heater. Water takes time to heat and cool, so there is no need for internet control, the timed control is just to line up with off-peak supply, there is a method using two elements often a switch on the immersion bath/sink and the external immersion Willis system so we can heat varying amounts of hot water, but can't see how this could be used with Hive?

 

[denso13]

I think it is far easier to fit a timer direct to the immersion heater.

He wants to use the Hive as the timer, which seems to be possible.

 

[ericmark]

He wants to use the Hive as the timer, which seems to be possible.

Yes, that is what I said, but price of single channel Wiser v double channel Wiser, was more than a timer would cost, not sure with Hive, I made a mistake, it sounded good when I got it, I go iboost+ so I can use spare solar, but solar paid at 12p/kWh and off-peak is 6.5p/kWh, so a simple timer would have saved me more money. So it only paid back for 20 months while getting the MPAN number sorted out.

The price of Hive seems to vary a lot, latter versions can do opentherm, and with a gas boiler that does seem a good idea, but although Wiser has the opentherm on single, double, and three channel versions, I note the instructions only advises its use with single channel.

I don't have opentherm, I do not even have a modulating boiler, so it does not concern me, when an oil boiler tends to last so long, so unlikely to need a replacement.

But a gas or oil boiler has a start-up and shut down time, whereas my immersion heater can run for a matter of seconds, and use between around 200 watt to 3 kW, and uses solid state control so it does not matter if it runs for one second, it is not wearing out contacts, cooling down or heating uptime is not a problem. I see the consumption following solar production as the solid state control varies what the immersion uses.

But both Wiser and Nest which I have fitted, have options for gas or oil, due to the changes in how often we want them to fire up, gas reacts faster than oil, think there is an electric option as well, so to use two different fuel types with the same controller would not be the best idea.

But it would work, but I repeat why would you want to?

 

[denso13]

But it would work, but I repeat why would you want to?

You are the biggest proponent of smart homes and odd set ups yet when someone asks a relatively innocent question you ask why? Just a bit odd...

 

[ericmark]

May be because I did make an error with iboost+, it seemed a great idea at the time, but my thoughts were flawed.

 

[Brian McHugh]

I was initially thinking of replacing my exiting upstairs single channel receiver with a two channel receiver and using the water heating output of this receiver to drive a 40A solid state relay controlling the immersion heater. After the new receiver arrived, I could see no way of altering the name of the water heating circuit on the upstairs receiver to ready Immersion Heater, and thereby distinguish it from the hotwater circuit driven by the gas boiler. I then contacted Hive - and they said it cannot be done, as Hive effectively does not support a single boiler driving two independently controlled tanks (or one tank plus immersion heater)!

I note the point "Why use Hive"?, but I already have a Hive setup and I wanted to keep everything within one system. I have read that it IS possible to use two 2-channel receivers in the same system, but just not to use the water heating circuit on the second two channel receiver.

I am going to try installing the new 2 channel receiver in addition to my existing single channel receiver controlling upstairs. I will then use the 'Heating' zone contact on the new 2 channel receiver to drive the relay rather than a two-port valve.

The prime reason for really wanting to stick with Hive for the immersion heater control is for the instant controllability, even when away from home. We have just had a solar panel and battery setup installed, and at the moment we do not get paid for any power exported to the grid. If I can get Hive to control the immersion heater, it is a simple matter to just use the 'Boost' facility to switch the immersion heater on for any period from 15 minutes WITHOUT having to program a regular event. In this way, I can usefully dump power into the hotwater tank in a very controlled manner if it looks like the battery is approaching full, so that we do not export electricity and benefit by not needing to turn the boiler on at all during the summer.