Weather Comp + independent zone valve

[JohnMo]

20 minutes ago, Mr Blobby said:

We have approx 200 litres, so I take it the manual is correct and an extra expansion vessel is required?

That sounds a lot, are you sure? But if correct, you will need an additional expansion vessel. Too much expansion room is better than not enough.

[Mr Blobby]

13 minutes ago, JohnMo said:

That sounds a lot, are you sure?

 

Ha, you're right, I used 16mm diameter for the UFH pipes, but the internal diameter is of course less.  😆

 

At 12mm ID the volume is just 118.  That's more like it 🙄

[SimonD]

28 minutes ago, Mr Blobby said:

The plumber (and hence the builder) are adamant that I need to mount it on rubber feet, despite advice from Panasonic to bolt the unit to the slab.  We'll see.

You don't need rubber feet on the Panasonics and you don't need to go to the expense of flexi connections to the heat pump either. You can buy and fit rubber feet if you want to and there is also a mounting frame available (with adjustable feet for uneven ground) if you need to install at greater height but this is usually only used for snow clearance. Yep, add another expansion vessel - shame it's not like the Viessmann boilers where there's a specified test procedure you can follow to determine if the built in vessel is sufficient, but it's quick and easy to add another.. 

 

36 minutes ago, Mr Blobby said:

A commissioning service is offered but no detail on pricing etc so I'm going to try to get this up and running myself. 

 

Given your UFH installation, a full commissioning service to balance your UFH will likely take days to do properly given the lag in a slab and also is best done when it's cold out. Just buy yourself a few pipe thermostats and stock up on patience.

 

On 27/05/2026 at 13:05, JohnMo said:

We have relaxed (simplified )that control and just use a room sensor to control everything,

Wow, I'm glad I was sitting down when I read this. @JohnMo has joined the dark side and gone room influence. I never thought I'd ever see the day given how adamant you used to be that it was akin to the devil 😉 What changed? Or is this another experiment?

[Mr Blobby]

We have a concrete pad already poured for the unit to sit on. Its a few inches above ground level.

 

Just seen this in my whatsapp from plumber/builder 🤷‍♂️

 

Edited yesterday at 11:26 by Mr Blobby

[JohnMo]

38 minutes ago, SimonD said:

Wow, I'm glad I was sitting down when I read this. @JohnMo has joined the dark side and gone room influence. I never thought I'd ever see the day given how adamant you used to be that it was akin to the devil 😉 What changed? Or is this another experiment

No not room influence - whole house, one room sensor/thermostat for whole house. Hiaer doesn't have a thermostat built into the controller. It is connected to outside temperature sensor so also allows oat switching the whole heat pump off in heating mode when outside is an average (over 6 hrs) above 10 degs.

 

No need to get excited, still single single zone, WC, no actuators, just an on off permission, mostly because running heat pump at 9 degs OAT on full WC at about 22 degs doesn't work, which is about the temperature it needs at that temperature. So heat pump uses a simple permission to run at 26 degs, runs for a couple of hours and then shuts off for about 18 hrs. The colder it gets the longer the run time.

 

No setbacks just single room temperature 24/7. But really needed for cooling as I run a set flow temp with humidity over ride. So makes sense to flick a single switch that takes thermostat from heat cool and same switch moves ASHP between heat cool also.

[JohnMo]

32 minutes ago, Mr Blobby said:

 

Just seen this in my whatsapp from plumber/builder

I used these to get the snow clearance needed to comply with OEM requirements for snow.

https://www.wolseley.co.uk/product/pump-house-1000mm-condensing-unit-mounting-block/?pid=P667987

[SimonD]

24 minutes ago, JohnMo said:

No not room influence - whole house, one room sensor/thermostat for whole house. Hiaer doesn't have a thermostat built into the controller. It is connected to outside temperature sensor so also allows oat switching the whole heat pump off in heating mode when outside is an average (over 6 hrs) above 10 degs.

 

No need to get excited, still single single zone, WC, no actuators, just an on off permission, mostly because running heat pump at 9 degs OAT on full WC at about 22 degs doesn't work, which is about the temperature it needs at that temperature. So heat pump uses a simple permission to run at 26 degs, runs for a couple of hours and then shuts off for about 18 hrs. The colder it gets the longer the run time.

 

No setbacks just single room temperature 24/7. But really needed for cooling as I run a set flow temp with humidity over ride. So makes sense to flick a single switch that takes thermostat from heat cool and same switch moves ASHP between heat cool also.

 

Hehe, what you've described is room influence, although the best room influence simply sends an additional signal to the heat pump to reduce the flow temps essentially modifying the WC curve. But if you have control from the room, that's room influence as it calls to the heat pump - nothing to do with actuators/open loop in an of themselves. Room influence is just about adding additional system control which uses the room conditions as input. 😁

[SimonD]

20 hours ago, Mr Blobby said:

We have a concrete pad already poured for the unit to sit on. Its a few inches above ground level.

 

What exact Panasonic model are you installing?

[Mr Blobby]

5 hours ago, SimonD said:

 

What exact Panasonic model are you installing?

 

J Series mono-bloc.  5kW.   https://www.aircon.panasonic.eu/GB_en/product/aquarea-high-performance-mono-bloc-j-generation-r32/

 

 

[SimonD]

9 minutes ago, Mr Blobby said:

 

J Series mono-bloc.  5kW.   https://www.aircon.panasonic.eu/GB_en/product/aquarea-high-performance-mono-bloc-j-generation-r32/

 

 

 

Ah, okay. How come you chose that over the newer r290 L series? Any particular technical reasons other than that the L series has to have an indoor unit?

[Mr Blobby]

So the heat pump has been delivered and it looks like it may actually be anthracite, which is remarkable, though it is difficult to see without taking all the cardboard off.

 

The heat pump manual states 22mm flaw and return.  I told the supplier this and I told him I did not want to "upgrade to 28mm".

 

The plumber subsequently spoke to his contact at the suppliers and the heat pump has turned up with 28mm bends (that were no on the original invoice I saw) and 28mm AF valves, and 28mm stop valves.  

The flow rate for this heat pump is just 14 l/min.  I imagine that is why the external pipework is specified at 22mm to maintain the velocity and minimise potential heat loss.  I texted the plumber yesterday to tell him that the pipework had to be 22mm, I guess I was too late and the supplier and plumber agreed to use 28mm regardless my instruction or panasonic specification.  The holes cored in the wall are sized for 22mm pipe and insulation, which I have on site.

 

I suppose that, with the 28mm bends and stop valves and AF valves that have been delivered, the plumber intends to install these and then reduce to 22mm. 

 

It may be that the holes cored in the wall, or at least one of them, is too low, so that the AF valve may need to be installed at the lowest point being the entry into the house, and not at the HP end, hence the 28mm valve may sit in the middle of 2 lengths of 22 mm copper.

 

Should I put my foot down and insist on 22mm AF valves and ball valves, or is it not a big deal?   

 

 

[Mr Blobby]

8 minutes ago, SimonD said:

 

Ah, okay. How come you chose that over the newer r290 L series? Any particular technical reasons other than that the L series has to have an indoor unit?

 

You guessed right, I didn't really want a split unit.  And also they are marketed as high temperature units, where I don't expect to ever want to go above 45 or 50 degrees for HW, much less for heating.

 

.. and they cost about a grand more.

 

Edited 4 hours ago by Mr Blobby

[SimonD]

14 minutes ago, Mr Blobby said:

Should I put my foot down and insist on 22mm AF valves and ball valves, or is it not a big deal?   

 

I think you need to have a word with them. As you say, with 5kW which won't be running at that for much of the time (other than during dhw), the 28mm pipe is just too big. Tell them to sort themselves out and do it properly. There is the option to use compression reducers with those fittings and use 22mm pipe for the rest of it - there are some pieces of equipment that only come with 28mm compression but the manufacturers chuck in the reducers for 22mm situations in the box.

But what do you mean by 28mm bends - not flexis surely as these units don't need flexis.

[Mr Blobby]

Thank you @SimonD for your response, which pretty much confirms my sentiment that they need to do it right, rather than what they always do.  What pees me off is the way these 28mm components turn up without any discussion when I have already asked for 22mm connections, as per the Panasonic install guide.

 

So the 1 1/4 28 mm AF valves are ok enough to use with reducers? 

I'm not sure what end of the pipe the valves sit and going 22 pipe  --->  28 AF valve ---> 22 pipe seems daft.

 

 

1 hour ago, SimonD said:

But what do you mean by 28mm bends - not flexis surely as these units don't need flexis.

 

Sorry, excuse the layperson language, I mean elbow.  Two 28mm press fit elbows were added to the order, they look like this https://www.screwfix.com/p/flomasta-copper-press-fit-equal-90-m-profile-elbows-28mm-2-pack/591ak

 

 

Edited 2 hours ago by Mr Blobby

[Mr Blobby]

AF valves are 1 1/4.  I think the plumber and supplier have assumed the AF valves connect directly to the 1 1/4 inch connecter on the side of the heatpump.  Which may not be the case.