Posted by: @ket_88

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Hi all, 

I've purchased the Ideal Logic Air 8 outdoor unit heat pump, along with the Ideal control box and the Elite standard 200l. This is an air to water heat pump for reference.

 

We have underfloor heating throughout the whole property, and the property has 3 floors so we wanted 3 zones so we can control the temperature on each floor. 

 

Reading the documentation, the recommended thermostat is the Halo Air. However, the maximum zones it can support seems to be 2 from reading the documentation here on Page 40:

https://assets.ctfassets.net/sj902orc9wh4/302lPtSPRuwj4lEoGouY6y/abb11291cdddfed6c60389e43fc626b9/IHD_230620_Heat_Pump_Brochure_RevC_Web.pd f" title="IDEALHEATING.COM" rel="nofollow" target="_blank" >

IDEALHEATING.COM "https://idealheating.com/_gatsby/file/f214e5268ddbf4494bc8f05dada8be9f/IHD_230620_Heat_Pump_Brochure_RevC_Web.pdf?u= https://assets.ctfassets.net/sj902orc9wh4/302lPtSPRuwj4lEoGouY6y/abb11291cdddfed6c60389e43fc626b9/IHD_230620_Heat_Pump_Brochure_RevC_Web.pd f"

I assume this is down to a limitation on the Halo air smart interface?

If I wanted a 3 zone setup can I buy any thermostat off the shelf like the Heatmiser Neo Air V3. If I purchase this do I need the Heatmiser UH8 to connect to the Ideal control box?

Or can I buy the Halo Air and just select 2 random thermostats like the Neo air V3 and have it all work together. 

Sorry if this is a basic question, but I can't seem to get any answers out of the team who are supplying the kit to us, and reading the documentation, it's not massively clear.  

Firstly thank you for posting and please be assured no question is 'basic'.  People here just want to help.

Please don't buy a third party controller not designed for a heat pump, else you will be back here complaining about poor efficiency.

Heat pumps are generally best run 24*7 with no external controls (unless specifically designed specifically for heat pumps which very few are), in most cases on a single zone.  Of course there are exceptions, but they are relatively rare.

The first question I would ask is why do you need 3 zones?

I would strongly suggest you also read this introduction to heat pumps as they have characteristics which are diffent to boilers, and as a result you need to forget almost everything you have been told about how to run heating systems.

If you would like to say a bit more about the house and the heating system I (or someone else) may be able to provide a bit more tailored advice.

@jamespa thanks for the reply.

We had originally gone for 3 zones as our builder had suggested 1 per floor as its a 3 storey townhouse. However, he hasn't had experience of heatpumps.

After doing more research it seems doing 1 would be a better option and using the one made the manufacturer makes sense.

I found this video which was helpful:

Fingers crossed my builder can connect up the heating still while the house is still open.

Ill have a read of the post you mention.

Thanks

Posted by: @ket_88

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We had originally gone for 3 zones as our builder had suggested 1 per floor as its a 3 storey townhouse. However, he hasn't had experience of heatpumps.

 

After doing more research it seems doing 1 would be a better option and using the one made the manufacturer makes sense.

No harm at all in plumbing it as 3 zones, I would have done the same, but you almost certainly want to control it as one.

The best starting point is to have no mixing, all zones open, heat pump operating 24*7, any timers set for 24*7 any third party thermostat set at least 2C above target so they act as limiters not controllers.  Then adjust the weather compensation settings down to the lowest possible consistent with just heating the house, changing the setting slowly (1degree/step per day at most) as you get close to the right value.  You may need to balance the zones using the flow regulating valves to get equal temperatures (or the desired temperature differences) if this hasn't already been done.  All this is best done mid season (when its coldest), but you can get a rough adjustment at the start of the season then tweak as it gets colder. 

Many people find that the most comfortable (and cheapest) way to run their heat pump is purely on weather compensation (which controls according to outdoor temperature), without any influence from the room temperature at all.  This is at first counter-intuitive, but actually there is a good engineering/physics reason why this is likely to work better than control based principally on room temperature, and is certainly the place to start.  

Its pretty much the polar opposite of how we run boilers in the UK (long story - you can run many boilers in exactly the same way as heat pumps and if you do so you are likely to have a more comfortable house and spend less on heating.  Some more enlightened countries do this but sadly we don't for the most part.  For boilers the cost penalty is perhaps 10%, for heat pumps it can be much, much more so becomes vital)

If you read the link I sent and then read the relevant bits of the manual for the heat pump and Halo hopefully it might make sense.  If it doesn't please feel free to ask and dont feel shy to do so, heat pump manuals aren't the easiest things to understand (although the Ideal one is much better than many) and there are some unfamiliar concepts to grasp.

By way of encouragement (hopefully) I run my (Vaillant) heat pump on pure weather compensation without room influence for most of the season (towards the end I do a tweak to deal with solar gain which at season end, is high compared with the load).  I have radiators on a single zone.  Only 2 have any form of individual control, a fan radiator which I fitted because I couldn't get a large enough conventional one in the space, and a radiator in a guest bedroom which has a TRV as a courtesy.  The remaining radiators are fitted with TRVs but they are set to maximum and the heads are unscrewed, so they are purely cosmetic.

The heating is 20% cheaper than my gas boiler was (a good choice of tariff helps) and the house is way more comfortable than it ever was with fancy controls. 

Can I ask how old the house is and the floor area.  8kW for a new build sounds potentially oversized.  There are strategies to deal with oversized heat pumps if that is the case, particularly if the UFH is in concrete.

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PS. I just reread the Ideal manual and, as I remember and one if the professionals on the forum has commented, it's pretty simple.  Ideal are part of a group that includes manufacturers in countries where WC has been mandatory for boilers for years and (like some others in a similar position) it shows, in that they have worked out a UI to a system based on wc that is about as simple as it could be.

For ufh there are only two WC curves recommend, a lower and a higher one.  Id be tempted to start with the lower and turn it up only if the house isn't warm enough.  

Layered on this is a 'room influence' adjustment between 1 and 100%. This is a bit mysterious but it clear that it displaces the WC curve according to the measured difference between the target room  temperature and actual. It's not clear what the %figure means, but I would guess it's a time constant for the displacement with low % being a long time constant and high % being a shorter time constant. They suggest 20-40% for ufh so, unless an 'Ideal' expert can comment otherwise, I would first set the target temp on the halo to your desired room temp and make sure it's somewhere sensible, then start the room influence factor in the middle of their suggested values and give it a few days to settle before thinking about whether to change it. Thereafter, If the room temperature tends to oscillate with a period of hours I'd turn down the room influence figure, if it takes a very long time to adjust I'd perhaps try turning it up.  This analysis is based on a bit of control theory and some assumptions about how it works.  The assumptions may be wrong (but the control theory is sound)

I think that timed changes in target room  temperature (up or down) work also by shifting the WC curve not by turning the unit on/off on a thermostat, which is how it should be.

In summary it looks like an excellent UI, far better than most of the far eastern brands.