Mr Blobby

When installing hot and cold manifolds, is it good practice to install a board on the blockwork first, and if so what? Pipes are mlcp into plant room.

Thanks. It's all oil heating here in Northern Ireland so heat pumps are a bit of a challenge. Once we get inside the house then the plumbing should be the same as any other system so I'm trusting my plumber to do all that wet stuff with his eyes closed. One last question, do you have a link to an extended ball valve 22mm, I think they are all 28. Or maybe I run 28 mm to the end of the ball valves and then reduce down to 22 🤔

So the AF valves delivered are Caleffi 108. Model 108701. https://www.advancedwater.co.uk/product/caleffi-antifreeze-valve-1-14-108701 AFAICS, no swivel on one side. On the quote the ball valves were like this... https://www.intatec.co.uk/products/k-type-extended-ball-valve/ But what has been delivered is this cheaper substitute, which isn't good: The 3 way valve is this VC6013MP6000 1 inch. Like this. https://www.kestakon.co.uk/3-way-valve-1-it-vc6013mp6000-honeywell-without-limit-switch/ Added to the delivery were 6 x 28 mm to 1.1/4 compression straight fittings and the two 28mm elbows. So I think I'll swap out the components for 22mm AF valves if I can get them, and decent, not economy, 22mm ball valves. Then it should be possible to connect the pipework from heatpump into the house without so many reducers everywhere. I think. 🤔 Perhaps the lesson here is to specify everything instead of relying on the heat pump supplier to configure the plumbing components. The people who supplied the heat pump do offer to do commissioning and sign off for the warranty but as yet have given no price for this service. I'm in no rush to ask them to do so. The first supplier we approached didn't even give us a price because I refused to have a buffer tank. I reckon our plumber can do all the wet work, our electrician the wiring. It may be that the risk of heat pump failure is too small and the cost of commissioning too high to make the the extra warranty worth it. I'll soon find out 😬

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.

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. 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

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.

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?

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

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 🤷‍♂️

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 🙄

First supplier I spoke to never came back with a quote after I told him I didn't want a buffer tank or actuators on the manifold. Second supplier should be delivering the panasonic heatpump in a few days time. A commissioning service is offered but no detail on pricing etc so I'm going to try to get this up and running myself. What could possibly go wrong 🤔 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. The unit has an expansion vessel inside for the heating circuit but the manual advises that for volume > 150 litres an additional expansion vessel must to be fitted. We have approx 200 litres, so I take it the manual is correct and an extra expansion vessel is required?

Still not heard back from the supplier/installer with prices. I don't think we will after I challenged his wisdom. In the meantime, I think our planning has been a bit suboptimal, which seems to happen a lot on our build. We have two holes cored for flow and return from plant room to heatpump on other side of wall, so that's ok. The question is what's the best way to run the data and power cables? The HP has 2 power connections so 2 isolators are required on the external wall. We do have two conduits through the slab from the plant room, one for power and one for data, but they exit about 5 metres around the corner from the heatpump, and may end up being more congested than I would like. What's best to do here? Run the cables through the slab and then through conduit on either the wall or underground to the heatpump? Or would it be neater to core out a three more holes for 2 power and one data in the wall to exit at the heatpump?

By Jingo, after much chin rubbing today, I am sold on the simplicity of a single zone 🧐 To give some flexibility, would it be possible and sensible to insert a manual balancing valve of some kind in the return of the FF manifold to reduce the flow if required, to increase the ΔT and reduce FF heat output to avoid any potential FF overheating? If so what valve to use?

I like the simplicity of this very much, and you are probably right that it would work given the lower heat FF output at wider centres (and timber covering). We had originally planned to install only GF loops, the FF loops were later added because of an increase in expected solar gain because we were unable to install planned external blinds on some windows. I think I may be stuck in a mindset that there should be some control to switch off the flow to FF loops just because they were originall excluded. Maybe not 🤔 I agree 👍.

Just spoke to the installer/supplier on the phone. He spent 10 minutes trying to convince me I needed actuators on the manifold, a buffer tank and a hitachi heat pump instead of Panasonic. And AC as well because passive houses always overheat. He's putting together a price list for all the Panasonic bits sans buffer.