Mr Blobby

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.

You make a good point here about wiring two zones back to the heat pump. It just seems unecessary to have a zone-1 valve and sensor at all, because the GF zone 1 valve will always be open so the zone valve is effectively redundant. We will never be running the FF heat without GF heat, but this is of course how Panasonic controllers expect normal people to run their heating with these options. The plan is for the first floor zone to be off most of the time, except maybe for cooling in wetaher like this, but I take your point. This is just an idea at this stage to have an open zone and an independant second zone. I had hoped that this was something more common that would be commented on here 😕 I have a spreadsheet that I put together ages ago, so a person not very sensible at all is responsible for the loops. I have completely forgotten how I arrived at the formulae and numbers but, in theory, we have about 11 W/M2 heat demand per room, and with 200 centres GF and 250 FF that should return 22C GF 20C FF with about 27/22 flow and return. Or something like that. It will be interesting to see if theory and practice are the same 🤔 I'm hopeful that the FF zone will not be used very often for heating and, if so, then mixed circuits are probably unecessary. In theory anyway. In theory the FF loops are primarily for cooling but with insulated screed underneath and engineered timber on top it may be that only the FF bathrooms with tiled floors get the cooling effect 😬

We have a decent plumber to do all the pipework, which I suspect is largely the same as he would normally do with an oil boiler, so I don't really need to do very much. At this stage the UVC (300L is biggest we can fit in undesized plant room) isn't even going in yet, this is just to get the heating on to get floor temps up before tiling. All I need to do is connect the electrics and the controller cables to the circuit board. In our simple configuration this looks breathtakingly simple. Frustrating as this is, I need to play the game and wait for the installer to come back with an unacceptable proposal before I can make a counter proposal. Heat pumps are rare here, builder and plumber see them as some mystical box that demand expert knowledge and they want an expert installer to hand this over to. I would be happy to take responsibility but theres a bit of a diplomacy dance to do first 🙄 I've read the manuals and and watched the you tube videos. What could possible go wrong? 😆

My thoughts exactly. We have a cooperative plumber who did all the first fix stuff who can join the pipes and stuff. But he wants to get his "installer" mate to supply and fit the heat pump. Builder is super keen to get the heat pump installed to get the floor temps up before tiling. I have sent him a link to buy the heat pump with a 12 day lead time, but he insists on waiting for plumbers mate to quote for supply and fit. We still haven't heard anything back from instalelr, but I think he is on holiday this week. Or he just isnt interested because I want some input into the design.

I had hoped to not have a wiring centre, but as you can tell I don't really know what I'm doing 😕 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 😂 I'll update here after I get the quote....

Hidden in the depths of the internet is the (strangely secret) release of the 5 kW monoblock in a way nicer anthracite. 😀 And is also a couple of hundred quid cheaper 🤔 WH-MDC05J3E5-1

No, no glycol, anti freeze valves for the freesing bit.

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

Should biocide and corrosion inhibitor be added to the water in the UFH pipes? Any reason not to? If so then what product?

Panasonic Aquarea installation manual says "Due to the high quality mounting system of the compressor and subsequent suppression of noise transmission, Panasonic Monobloc units do not require flexible hoses to transition from the Heat Pump to the pipe work used in the installation." This sounds too good to be true. What about rubber feet underneath? Anyone installing Panasonic units, is it ok to install straight onto the concrete base without rubber feet, and omit flexible hoses?

It doesn't look like it in the first picture I posted above because the bracket is this side of the roof, but if I put a straight edge on the roof it runs straight to the inside of the gutter. It doesnt lie over the top of the gutter, so even if the rain ran off at sepped in a straight line, it would still land in the gutter ok. I think the important thing to do is ask your metal roof supplier how they want it.

Good point, and I;m glad you reminded me about this. If I knew back then what I know now I would have insisted on 150 guttering instead of our builder ordering standard stock items from his regular merchant. We have a large roof but there should have been only one downpipe on the front of the house. It turns out that one downpipe needs 150 gutter to accomodate the flow. There's a set of regulations somewhere of gutter sizes required for roof sizes. It also specifies a fall towards the downpipe. Nobody on our site read it except me, and then too late. Fall, what fall?

Our metal roof supplier told the joiners what was needed for this. He told our joiners to leave about 20 mm wall plate overhang for the gutter brackets and these were installed prior to the metal roof. ... which is great, but, the roof supplier didn't plan the metal detail for the gable end / gutter correctly. There should be an allowance at the gable end so that the gutter can continue through. Look at the photo below and you can see what the issue is. The metal on the gable end stops the gutter running through to an end cap. We had to butcher it to make it right. Its worth checking with your metal roof installer that they will cater for this properly. Unlike our roof 🙄

... have I understood this correctly? A decoupling mat removes the need for expansion joints at door thresholds?

... thanks, this matches the builders preference to spray then touch up. 👍

This is probably a stupid question, but that doesn't normally stop me so here goes... Plastering is done and it seems pretty good I think, but there are the dings and cracks in the usual places. We will be getting the place spray painted as soon as SWMBO can decide a colour. Would it be sensible to fill in some cracks now before painting, or (as builder suggests) do this after the place is sprayed. Is the raw plaster too absorbant to repair before painting? Most of the cracks are only hairline, this one about 1 mm is the widest. A few dings where trades (and myself) have bashed into the walls. I read somewhere that cracks should be dremmeled wider and then flexible filler used, is that a good idea to treat the few bigger cracks?

Our K Rend is applied on on our block walls up to the window frame. Which is fine. What is best practice for the (in most places hairline) crack at the join between frame and render? Leave it or run a bead of silicone over it?

This sentimental love of coal power is rather amusing. Having woked at several power stations over the years here's some differences to consider. In a coal power station there is a coal plant, that is run by a team of staff constantly unloading coal froom trains or ships and moving it around a pile and then loading it onto conveyors into the main plant buiildings. The coal then runs along a conveyor, through a pulveriser and blown into the furnace. This heats up a boiler to create steam to drive the turbine. There is then the various de-sulphuristaion and nox plants to run, and a team of chemists to constantly monitor the emissions. Then there is the ash that comes out of the other end and needs to be disposed of. Some of this is sold to the cement industry but most of it ends up in landfill on which the station pays landfill tax. And there is a lot of ash. To start up a coal plant from cold takes about a day to heat up the boiler and synchronise. Ramp times are slow. This is not very useful in an energy system where generators need to be flexible and responsive. Units that can synchronise and ramp up quickly, run for 20 minutes and then desynchroise are king. Generators that stay on and run at constant load are of little benefit. They displace wind power (that is effectively free) when its windy and can't ramp up when it isn't. (hint:nuclear) Running a coal power station requires lots of moving parts, a lot of land, and lots of people. It is contunuously labour and capital intensive. And dirty. It is simply not economically viable to run a coal power station compared to gas. A gas power station has one guy in a control room. He presses a button to start and stop the turbine. No emissions, no ash, no coal plant. And it goes from off (windy) to full load (not so windy) within minutes.

The protective film on our aluclad frames has been on for about two years. I went to remove it today. Oh dear. North facing wiondows are ok but on the (many) South facing windows are a nightmare. The film has dried out, is brittle and does not want to come off the frame. Is there any easy way to remove the film, or do I have to spend the next week scraping it off with my thumbnails millimetre by millimetre ? 😫

Not all panels are the same. Two differences I think, colour and size. Some are all-black, and some have the wires showing. The latter are cheaper. AFAICS the panels you are looking at have the visible wires. Then, in the all-black category, some, such as JA solar are emarketed as all black but up close you can see the wires. The other, like the N type, from AIKO are all black with no visible wires. Which I think look awesome, if that's relevant to you, and also not too expensive. In terms of size, 1750 is traditional size. 500W panels tend to be bigger at 1950, but the power per area is not really any better. Yes, I never understood how having cells on the underside of the panels to ostensibly acheive a higher power rating was anything but a scam.