WC + independant zone valve

[Mr Blobby]

So this month is heat pump month, and I am seriously excited about it.  The challenge will be, however, to convince our builder and plumber not to hand over total control of the ASHP install to a third party installer.  Thanks to the useful guidance on this forum and the low heat demand in our house, I am keen to run WC mode without any buffer tank or additional pumps if possible.  I suspect the third party installer would prefer a more expensive, less efficient design.  I will soon find out.

 

We have two UFH manifolds, GF and FF.  It would be nice to treat the FF manifold as a seperate zone.  The GF zone will always be open and should have enough volume to satisfy the flow requirement of the pump. 

 

The panasonic text book provides a direct (no buffer) 2-zone implementation but requires flow temp sensors on both zones and valves on each zone, all connected back to an additinal circuit board in the ASHP.  I'm not convinced it needs to be that complicated and chat gpt concurs.

 

I think there is a far simpler solution, to configure the system as a single zone, bog standard WC implementation, but then install a two port valve before the FF manifold connected directly to a thermostat on the first floor.  This would provide a way of isolating the zone altogether.  The heat pump would not need to know about this seperate zone.  A thermostat with cooling function seems to be available that would cool down to cooling setpoint so, when the heatpump is set to cooling mode, then the FF thermostat would also be able to open the zone valve to the FF if the FF is overheating.

 

The simplicity and low cost of this design appeals greatly.  No additional flow temp sensors, one zone valve, no additional circuit board.  What's not to like?

 

Is this standard stuff, do others on this forum control zones like this, perhaps to switch fancoils in/out, with an indepentant thermostat/relay/valvethat is wholly independant of the ASHP?  Or is is bonkers?

 

 

(The more complicated, integrated panasonic implementation is in the attached pdf)

 

 

 Direct two zone third party controls 5kW 7kW 9kW.pdf

Edited 17 hours ago by Mr Blobby

[JohnMo]

We used an external permissive to start stop the ASHP. So similar to what you propose.

 

For me knowing what's going on is important, so I have used a wiring centre for the UFH, this is equipped with room sensors, not thermostats. The signal from the wiring centre goes directly to ASHP, not to UFH actuators etc. The whole system can also be moved between heat and cool via a volt free signal. So open circuit is heating mode closed is cooling mode. ASHP using the same signal, so use a single switch to move both the UFH wiring centre and ASHP between the two modes.

 

We have in effect two heated areas the house and summer house. After quite a bit of experimentation figured I could run as a single zone and either the summer house or the house could call for heat, and both got heated together. The house floor acting as a buffer. Running for an hour or so to heat up the summer house has zero effect the house.

 

Have run pure WC and if you can do that, I would, but we have found using the wiring centre and it's sensors, giving the heat pump permission to run, meant we ran better and could keep away from min modulation longer and regularly get CoP of 5+.

 

I would try to run as a single zone, decrease the upstairs output with reduced loop flow where needed. You are going to running very low temps, our curve starts at 26 degs at 10 Deg oat and goes to a massive 28 at -5 degs. So likely hood of overheating is zero.

 

I would make sure price wise you are not being screwed over

7 hours ago, Mr Blobby said:

builder and plumber not to hand over total control of the ASHP install to a third party installer. 

So MCS uplift and plenty with a profit to make

[Mr Blobby]

2 hours ago, JohnMo said:

I have used a wiring centre for the UFH

 

I had hoped to not have a wiring centre, but as you can tell I don't really know what I'm doing 😕

 

 

2 hours ago, JohnMo said:

 

I would make sure price wise you are not being screwed over

 

Exactly this. 

The heat pump costs £2,599 ex VAT.  How much can they charge to install this?    My guess is minimum 6k for a days work.  Maybe more.  Maybe I'm being too cynical. 

 

Although I've told the plumber I want WC and no buffer so we may never hear back from the installer 😂

 

2 hours ago, JohnMo said:

So MCS uplift and plenty with a profit to make

 

I'll update here after I get the quote....

 

Edited 8 hours ago by Mr Blobby

[JohnMo]

11 minutes ago, Mr Blobby said:

had hoped to not have a wiring centre, but as you can tell I don't really know what I'm doing 

Just choose a wireless thermostat that switches between cool and heat easily - I say wireless then you can move it to where it gives the best representative house temperature. But the Panasonic controller has one built-in (pretty sure), just use this. It should do cool and heat out the box.

[Nickfromwales]

59 minutes ago, Mr Blobby said:

My guess is minimum 6k for a days work.  Maybe more.

I’m on my way.
 

I can do it for £5999, on mates rates.

 

Can’t you just find a decent local plumber (“heating engineer……”) to put pipes from A-B with you supplying?

 

It’s ridiculously simple work, easier than putting a combi boiler in.