Which ASHP are set up to cool

[m0deller]

Active cooling enabled , and I've manually set a circuit to manually cooling .. but nothing so far 😞 Anyone else got this working on the aerotherm plus?

[Dan F]

16 minutes ago, m0deller said:

Active cooling enabled , and I've manually set a circuit to manually cooling .. but nothing so far 😞 Anyone else got this working on the aerotherm plus?

I have, been installed since Jan.  Have been using cooling on/off for last few months.  Main issue I have is my UFH is in passive-slab and the only way of controlling cooling is via the Vaillant controls which isn't suitable really as room temp lags slab temp.

[Dreadnaught]

1 hour ago, Dan F said:

Main issue I have is my UFH is in passive-slab and the only way of controlling cooling is via the Vaillant controls which isn't suitable really as room temp lags slab temp.

 

I am following this discussion with great interest. I haven't bought my ASHP yet but was planning to use exactly the same setup as you @Dan F, including with a passive slab.

 

I have had a play with the VRC720 online simulator and read the manual. For controlling the cooling, there seems to be a number of controls available. Do they not meet your needs?

 

It is unclear to me if the cooling circuit uses weather compensation or if that is limited only to heating. If not, then how is the water temperature set in cooling mode?

 

@m0deller, in MENU → SETTINGS → Installer level → Installation configuration
→ Installation → Automatic cooling. Have you turned this on to automatic and set the two temp setting appropriately? See below.

 

[Dan F]

28 minutes ago, Dreadnaught said:

I have had a play with the VRC720 online simulator and read the manual. For controlling the cooling, there seems to be a number of controls available. Do they not meet your needs?

The issue is that the controller uses room temperature and if I put 21C it will cool slab for too long, and the next morning the ground floor rooms will be too cold because (due to the lag in room temperature) it will have cooled the slab too much.  The heating function can be enabled/disbaled via a dry-contact or you can use Loxone/EEBus to set the heating mode/setpoint based on slab temperature (or if you want slab temp, room temp, exterior temp and forcast), but there is no such functionality for cooling, you have to use the Vaillant app or controllor both of which use the temperature sensor in the controller.

 

28 minutes ago, Dreadnaught said:

It is unclear to me if the cooling circuit uses weather compensation or if that is limited only to heating. If not, then how is the water temperature set in cooling mode?

I don't know for certain, but I'm 90% sure it is not using weather compensation from what I've seen.  The water temperatue for cooling is:

min(configuredMinCoolingTemp, calculatedDewPoint + configuredDewPointOffset)    (both min temp and dew point offset can be set per circuit if you have more than one. e.g. UFH + fan coils.  Also dew-point monitoring can be disabled for a given circuit).

 

I have the following configured:

UFH:
- dew-point monitoring: on

- dew-point offset: 2K

- minTemp: 15C

ComfoPost:
- dew-point monitoring: off

- minTemp: 7C

 

[Dreadnaught]

7 minutes ago, Dan F said:

The issue is that the controller uses room temperature and if I put 21C it will cool slab for too long, and the next morning the ground floor rooms will be too cold because (due to the lag in room temperature) it will have cooled the slab too much.  

 

 

Makes sense. Thank you. Sounds like it may be wise to constrain the cooling with a higher minimum temperature and perhaps a shorter cooling window. Not ideal, short of directing the controller to watch a sensor embedded within the slab (or the temperature of the return water in the UFH pipes).

[Nickfromwales]

4 hours ago, Dan F said:

I have, been installed since Jan.  Have been using cooling on/off for last few months.  Main issue I have is my UFH is in passive-slab and the only way of controlling cooling is via the Vaillant controls which isn't suitable really as room temp lags slab temp.

Same issue I'm having hitting a sweet spot with a clients build...... Slab and house temps have such a slow response vs what the system "expects".

Prevention vs cure is paramount criteria.

[Nickfromwales]

1 hour ago, Dan F said:

minTemp: 15C

I started off at 17, but it wasn't aggressive enough, so went to 16. I thought the hysteresis would be a problem if i went to 15, with the stat cutting out at 14, and back in again at 16. Trial and error atm. Also very difficult to manipulate this in the recent spate of uber hot weather.

The UK is not "cooling friendly", that's the biggest issue. Add in a passive raft and extended decrement delay / very long thermal time constants etc and it's is ( IMHO ) near impossible to remove the 'human' element for ultimate control ( via prediction and reaction ).

[jack]

2 minutes ago, Nickfromwales said:

I started off at 17, but it wasn't aggressive enough, so went to 16. I thought the hysteresis would be a problem if i went to 15, with the stat cutting out at 14, and back in again at 16. Trial and error atm. Also very difficult to manipulate this in the recent spate of uber hot weather.

The UK is not "cooling friendly", that's the biggest issue. Add in a passive raft and extended decrement delay / very long thermal time constants etc and it's is ( IMHO ) near impossible to remove the 'human' element for ultimate control ( via prediction and reaction ).

 

Interesting. This isn't my experience at all.

 

I just have mine set to output 15 or 16 degree water (can't remember which) and turn it on manually when the house is too hot or there's a heatwave predicted. I run the cooling open loop - no separate thermostat.

 

I don't care if the floor's a bit cold underfoot, but realistically the downstairs floor temperature never drops below 19 degrees or so.

 

I had it running for a few days in a row when things were really bad a couple of weeks back and it worked perfectly. It's lovely to come downstairs when it's been hot overnight and feel the steel banister get colder and colder with every step!

 

I do wonder whether having polished concrete floors helps. I imagine it absorbs heat from the air pretty well compared to, eg, wood.

[Nickfromwales]

1 minute ago, jack said:

Interesting. This isn't my experience at all.

 

2 minutes ago, jack said:

and turn it on manually when the house is too hot or there's a heatwave predicted. I run the cooling open loop - no separate thermostat.

10 minutes ago, Nickfromwales said:

it's is ( IMHO ) near impossible to remove the 'human' element for ultimate control ( via prediction and reaction ).

My points in a nutshell.... ?

[Dan F]

31 minutes ago, jack said:

I had it running for a few days in a row when things were really bad a couple of weeks back and it worked perfectly.

You manually turn if on/off though, right?  That's what I'm having to do.. but my argument is that given I have temp sensors in the slab and I know all room and exterior temperature too, there shouldn't really need to be anything manual about it.

[Nickfromwales]

10 hours ago, Dan F said:

You manually turn if on/off though, right?  That's what I'm having to do.. but my argument is that given I have temp sensors in the slab and I know all room and exterior temperature too, there shouldn't really need to be anything manual about it.

Where do you tell the system how long it takes for action to convert in to a reaction? You can’t, ergo ‘human intervention’ for cooling is inevitable for these sporadic overheat events afaic.

 

@jack, when do you initiate you’re cooling? Crack of dawn on a day where you expect to be uncomfortably hot? The night before? 

[jack]

  

11 hours ago, Nickfromwales said:

My points in a nutshell.... ?

 

Not exactly. I was responding to these points: 

 

11 hours ago, Nickfromwales said:

Also very difficult to manipulate this in the recent spate of uber hot weather. 

...

The UK is not "cooling friendly", that's the biggest issue. Add in a passive raft and extended decrement delay / very long thermal time constants etc and it's is ( IMHO ) near impossible to remove the 'human' element for ultimate control ( via prediction and reaction ).

 

You're talking about control theory problems that arise out of system behaviour - time constants, cycling, flow temps, etc - but my experience doesn't agree with that.

 

My point was that I can push one button on the ASHP controller and leave the cooling system on for days if needed, without any further intervention. Even without any form of thermostatic control, it will happily keep the downstairs area pleasantly cool without me having to turn it on and off or adjust flow temps to keep things comfortable. 

 

The question of manual control is a bit of a red herring in my response. I control it manually because I want to choose when I consume energy for cooling, not because I have the problem with automated control that you describe. 

 

I may eventually get around to installing a timer (and maybe even a thermostat), and perhaps control it via Loxone. But at the moment, it works perfectly well just turning it on and off when I feel it's needed.

 

10 hours ago, Dan F said:

You manually turn if on/off though, right?  That's what I'm having to do.. but my argument is that given I have temp sensors in the slab and I know all room and exterior temperature too, there shouldn't really need to be anything manual about it.

 

Sure, but my comment was in reply to Nick's regarding his problems with control theory issues like time constants and temperature stability. You have an interface problem, which, while frustrating, is not what I was talking about. 
 

16 minutes ago, Nickfromwales said:

@jack, when do you initiate you’re cooling? Crack of dawn on a day where you expect to be uncomfortably hot? The night before? 

 

In the warm weather leading up to the big heat wave recently, I was running it most days during daylight hours to use as much PV as possible. I forgot on the odd day but it didn't make much difference. Even without intervention, it takes a good couple of days for the slab to warm up when the weather's hot.

 

A couple of days before the record day, I started leaving it on 24 hours day. I left it on continuously for maybe 5 or 6 days that really hot week. Edited to add: Hence, this:

 

16 minutes ago, Nickfromwales said:

You can’t, ergo ‘human intervention’ for cooling is inevitable for these sporadic overheat events afaic.

 

... is not my experience, despite the fact that I have to manually choose to turn the system on.

 

More generally, if I know it's going to be a warm day, I'll turn it on if I think of it in the morning. It takes a few hours to kick in, but the slab time constant is so long that even if I forget on a hot day, it doesn't make that much difference.

The cooling's been off now for a few days and the floor is still slightly cool underfoot despite the temperature having been in the 20s this week. I do think that concrete, and presumably similar surfaces such as tile, are just inherently more comfortable in warmer weather. 

[Dan F]

43 minutes ago, jack said:

Even without any form of thermostatic control, it will happily keep the downstairs area pleasantly cool without me having to turn it on and off or adjust flow temps to keep things comfortable. 

I see that it takes at least 24hrs for our slab to increase 1C in hot weather. ASHP then takes 5-8hrs to remove 1C depending on flow temp (adjusted automatically based on dew point) and ufh pump speed (which is was playing with).

 

So while i am using manual control, and im annoyed i cant automate this easily with Vailant, like Jack it is only minimal on/offs required.

[jack]

18 minutes ago, Dan F said:

I see that it takes at least 24hrs for our slab to increase 1C in hot weather. ASHP then takes 5-8hrs to remove 1C depending on flow temp

 

I don't have the actual numbers for my setup, but what you've recorded seems similar to my subjective understanding of how my house responds.

[Dreadnaught]

@Dan F, I see that the controls on the VRC720 allows for a given Zone to be controlled by a remote control. Could it be possible to connect your slab thermistor to a remote control in some way and then link it to a zone. That way the controller could target a slab temperature for the ASHP rather than a room temperature and so give you finer control. No use of exotic ebus commands required. Just an idea.

 

@Dan F, with your background in software & technology, I suspect you're more ingenious than I.

Edited July 30, 2022 by Dreadnaught

[Dan F]

23 minutes ago, Dreadnaught said:

@Dan F, I see that the controls on the VRC720 allows for a given Zone to be controlled by a remote control. Could it be possible to connect your slab thermistor to a remote control in some way and then link it to a zone. That way the controller could target a slab temperature for the ASHP rather than a room temperature and so give you finer control. No use of exotic ebus commands required. Just an idea.

Not really.  All thermistors are 1-wire and connections (to a 1-wire bus using cat7 cable) are all hidden in the plastered walls.  Even if I did have access to one, I'm not sure it would be easy to break open the thermostat and wire-in a third-party sensor.

 

23 minutes ago, Dreadnaught said:

@Dan F, with your background in software & technology, I suspect you're more ingenious than I.

A lot of ASHP manufacturers have a Modbus interface, Vaillant only has EEBus which is quite limited.  Vaillant promised a Modbus gatewat over 2yrs ago [1] but nothing is available (at least in U.K) yet.  The only other option is to use eBus [2], but this is somewhat more complex and required a non-vaillant eBus coupler and then you need to discover the registers/operations available and I haven't seen any comprehensive documention for this (Vaillant clearly don't publish it as ebus, for them, is an internal protocol).  @m0deller has had some sucess with this already though, so the issue with cooling not being contollable by EEBus is enough motivation to try to follow in his footsteps.

 

[1] https://www.vaillant-group.com/news-centre/web-special-online-press-conference/neue-regelungen-fuer-mehr-komfort-neues-gateway-fuer-ausfuehrliches-monitoring-1-1680893.html

[2] https://github.com/john30/ebusd

 

[MikeSharp01]

7 minutes ago, jack said:

Even without any form of thermostatic control, it will happily keep the downstairs area pleasantly cool without me having to turn it on and off or adjust flow temps to keep things comfortable. 

I suppose there is a chance that you have hit the sweet spot? I wonder how the ASHP is cycling do you have any details of that?  

 

Sorry if I don't recall your upstairs temperature management systems but you, and others, talk about it getting a bit warm upstairs over the past heatwave. So I have been looking at cooling for upstairs in our build but I do wonder if some sort of stirring system to pick up air from just above the slab or push warm air down to the slab (EG simple convection) might be a way forward. 

[m0deller]

We have cooling!

When I looked last night, the Outdoor temp 24hr average menu item (sensoComfort Installer menu) wasn't displayed. I've looked this morning and it's now there. Looks like it needs 12hrs or so to start calculating the avg.  I can now manually enable cooling. 

Planning on using it via timed mode to make use of solar PV. 

 

[jack]

5 hours ago, MikeSharp01 said:

I suppose there is a chance that you have hit the sweet spot? I wonder how the ASHP is cycling do you have any details of that?  

 

I suspect I've been a bit lucky with the sweet spot. 

 

No idea about cycling, but it's a good question. I think it's more likely to be a bigger issue when leaving it cooling for several days, rather than just for a few hours through the middle part of the day.

[volcane]

I have my Daikin 8Kw split set to cool.

 

I had issues with supply of the unit as nobody said they could support cooling. The Daikin literature describes in detail the cooling aspect and controls but has never been supplied in Ireland, at least not last year.

 

Eventually I managed supply and fit but then all sorts of control issues. I had to settle for a simple cool on or off, controlled by a simple timer. I have the flow temp set to 15, after a bit of experimentation. I can isolate the living or bedroom section.

 

It worked well during the hot spell, we were away for 5 days and I was able to remotely activate the heatpump to make sure the house was cool on our return. The total energy used is minimal, just a pity we don't yet have PV.

We have no bedrooms above the living dining area to avoid any overheating.

[Exit]

Hi All, is there anyone who knows how i can activate the cooling on an Midea air source  heatpump. i was able to set it to cooling but its also showing OFF. 

 

I have reduced the temperature for the thermostat and the status still shows off. Please if you have any ideas let me know

[m0deller]

Contact Freedom heat pumps? They are the importer in the UK

 

[Bob77]

On 31/07/2022 at 15:54, volcane said:

I have my Daikin 8Kw split set to cool.

 

I had issues with supply of the unit as nobody said they could support cooling. The Daikin literature describes in detail the cooling aspect and controls but has never been supplied in Ireland, at least not last year.

 

There are various models of the Daikin split system, some of which support cooling and some of which don’t (I believe the code EHVH means heating only, EHVX means cooling as well).

 

Unfortunately when I ordered mine back in spring, the thought of cooling hadn’t crossed my mind, and changing the order would have delayed installation by several months, so I will be stuck with no cooling option. 

[DanT]

12 hours ago, Bob77 said:

There are various models of the Daikin split system, some of which support cooling and some of which don’t (I believe the code EHVH means heating only, EHVX means cooling as well).

 

Unfortunately when I ordered mine back in spring, the thought of cooling hadn’t crossed my mind, and changing the order would have delayed installation by several months, so I will be stuck with no cooling option. 

We had the same problem- bought a 6Kw split model that was heating only. But found that Daikin supply a conversion kit (about £150 I think) to add a condensate tray and different pressure sensor, then you need to cut a link on the board to enable cooling. I fitted it a month ago and it work’s really well with a fan coil. Couldn’t find a uk supplier though so bought it from a French company. Can dig out the details if you’re interested 

[Bob77]

6 hours ago, DanT said:

We had the same problem- bought a 6Kw split model that was heating only. But found that Daikin supply a conversion kit (about £150 I think) to add a condensate tray and different pressure sensor, then you need to cut a link on the board to enable cooling. I fitted it a month ago and it work’s really well with a fan coil. Couldn’t find a uk supplier though so bought it from a French company. Can dig out the details if you’re interested 

Yes I’d definitely be interested in that. Sounds like a cheaper option than going for separate AC.