Smart control for Fan Coil Units

[nikotime]

Hey all,

 

In the early stages of our self build and I'm thinking about heating and cooling for upstairs. It seems all the cool kids are doing UFH downstairs and using Fan Coils upstairs hooked up to an ASHP for supplemental heating/cooling which seems promising (e.g. Myson iVector S2).

 

What I have been struggling in my research is any way to make them smart and integrate them with my home automation setup (Home Assistant). How are you controlling the systems to facilitate heating and cooling controls? 

 

Cheers

Nick

[JohnMo]

6 minutes ago, nikotime said:

Myson iVector S2

They can take an external thermostat and recommend them doing cooling. Think you need 0-10v thermostat and they are generally hard wired connection.

 

We have a iVector in our summer house and it is supplied with water from the heat pump based on the house WC curve and just have the fan speed fixed at its lowest setting. Which works pretty well. Our summer house although insulated has a very different heating characteristics to the house but seems to cope well, so in a bedroom it's an easy job.

 

But with a heat pump, do you need any smart controls? For UFH you definitely don't and they really are a waste of time and money, due to the time lag involved, with the mass of the floor and low temp heating.

 

 

[nikotime]

1 minute ago, JohnMo said:

They can take an external thermostat and recommend them doing cooling. Think you need 0-10v thermostat and they are generally hard wired connection.

 

We have a iVector in our summer house and it is supplied with water from the heat pump based on the house WC curve and just have the fan speed fixed at its lowest setting. Which works pretty well. Our summer house although insulated has a very different heating characteristics to the house but seems to cope well, so in a bedroom it's an easy job.

 

But with a heat pump, do you need any smart controls? For UFH you definitely don't and they really are a waste of time and money, due to the time lag involved, with the mass of the floor and low temp heating.

 

 

Oh interesting. Yes for UFH I certainly wasn't thinking any smart controls from a reactive sense due to aforementioned time lag, but it is the sort of thing I'd want to play around with for automated scheduling based upon data I gather in Home Assistant.

 

For Fan Coils I am more thinking about individual room toggles and cost efficiency with cooling. E.g. turning up the speed on cooling mode only in rooms where we want them, turn them down at night for noise, etc. Your 0-10v thermostat phrasing sent me to this: https://heatmisershop.co.uk/heatmiser-neostat-hc1-0-10v-smart-fan-coil-thermostat/ which has a hub which I can integrate with Home Assistant it seems, so that might be a winner.

 

That's really interesting that you can just leave it fixed at its lowest setting - I certainly seem to be overcomplicating things than necessary - is that the case for cooling as well or do you only use it for heating in your summer house?

 

Definitely food for thought.

[JohnMo]

20 minutes ago, nikotime said:

Your 0-10v

You can also get a shelly 0-10v output relay. That would integrate directly in to HA.

 

21 minutes ago, nikotime said:

 

That's really interesting that you can just leave it fixed at its lowest setting - I certainly seem to be overcomplicating things than necessary - is that the case for cooling as well or do you only use it for heating in your summer house

I just run it fixed speed 24/7/365, so it gets heating and cooling. The cooling in house (via UFH) is a very flat WC curve and I leave that on all the time during summer and the heat pumps just seems to run when the sun's out. 

[Iceverge]

Are you actually saving anything by running the fan coils from the ASHP? 

 

I would say a multi split A2A unit with it's own external unit might be just as easy. You would have redundancy for heating if yiu picked the correct units. 

 

Our WiFi enabled Daikin FTXM25R has been plugged in and running for the last few days. It's got an interface to Alexa Google home etc if you want that. 

 

I'll do a post about it when I have more time but so far the app control is pretty good but the performance and interface has been impressive so far. 

 

[nikotime]

1 hour ago, JohnMo said:

You can also get a shelly 0-10v output relay. That would integrate directly in to HA.

 

I just run it fixed speed 24/7/365, so it gets heating and cooling. The cooling in house (via UFH) is a very flat WC curve and I leave that on all the time during summer and the heat pumps just seems to run when the sun's out. 

 

Thanks! I guess the Shelly would just trigger it off or on, but that is definitely a simple way of doing things if I'm happy with the fan speed and that the heat pump can just do its thing. 

 

1 hour ago, Iceverge said:

Are you actually saving anything by running the fan coils from the ASHP? 

 

I would say a multi split A2A unit with it's own external unit might be just as easy. You would have redundancy for heating if yiu picked the correct units. 

 

Our WiFi enabled Daikin FTXM25R has been plugged in and running for the last few days. It's got an interface to Alexa Google home etc if you want that. 

 

I'll do a post about it when I have more time but so far the app control is pretty good but the performance and interface has been impressive so far. 

 

I think I didn't want to rely on A2A for heating as it 'felt' more inefficient than using fan coils given the ASHP would be running at the same time anyway with UFH/UFC.  We are projected by our electrician on our single phase setup to be running close to the limit without it so fan coil has much less electric usage. 

 

Probably need to wait til we run the calcs but wanted to start from a (relatively) informed place! 

 

[JohnMo]

25 minutes ago, nikotime said:

Thanks! I guess the Shelly would just trigger it off or on,

actually does a 0-10V output to would provide modulation of output

27 minutes ago, nikotime said:

We are projected by our electrician on our single phase setup to be running close to the limit

Is this really the case? I suspect not, maybe if you added every user together, and switched them all on at the same time - but doesn't happen in real life.

[nikotime]

23 minutes ago, JohnMo said:

actually does a 0-10V output to would provide modulation of output

Is this really the case? I suspect not, maybe if you added every user together, and switched them all on at the same time - but doesn't happen in real life.

Ohhhhh that is very cool on the Shelly front!

 

And my electrician who did the calcs basically warned me to not add any air con to my existing plans 😆 but it sounds like maybe there are ways around that.

EDIT: P.S Appreciate your posts around weather compensation (including to another person today!). Doing a lot of reading now into this approach instead

Edited November 22 by nikotime

[Iceverge]

8 hours ago, nikotime said:

 

Thanks! I guess the Shelly would just trigger it off or on, but that is definitely a simple way of doing things if I'm happy with the fan speed and that the heat pump can just do its thing. 

 

I think I didn't want to rely on A2A for heating as it 'felt' more inefficient than using fan coils given the ASHP would be running at the same time anyway with UFH/UFC.  We are projected by our electrician on our single phase setup to be running close to the limit without it so fan coil has much less electric usage. 

 

Probably need to wait til we run the calcs but wanted to start from a (relatively) informed place! 

 

 

Why don't you put UFH upstairs too?

 

Simpler is always better.

 

I would avoid too much tech because it's expensive to buy, relies on externally controlled software and when the day comes to pay someone to fix it you (or your loved ones more lightly) don't want to be giving them 2 days wages just to read the manual.