Dreadnaught

Thanks Nick. No. I won't be asking for this. I wonder if the Arotherm Plus ASHP will be available in the "Products Characteristics Database" for SAP. Does anybody know? I've emailed my SAP assessor to ask. Did you mean "aren't" rather rather than "are"?

Don't count on spending that £5k from the BUS. An ASHP install that would cost £6,000 will magically cost £11,000 under the bus ("there is so much paperwork don't you know"). I am buying the ASHP myself and will use a local air-conditioning engineer to install, 1- or 2-days work max. No BUS for me.

The foil you mention sounds like a likely culprit of the poor signal. In an Amazon review of a foil breather membrane someone commented on losing their Wifi signal once they had it installed. Signal of -68 dB is poor for 4-meters. You have mentioned the possibility that metal objects may cause interference. Alternatively, are there any devices in the vicinity that can cause interference at 2.4 Ghz frequency: microwave oven, old fridge, baby monitor, a neighbour using the same WiFi band as you? Do you have other Access Points (APs) in the house? Are you sure that the Ring doorbell is connecting to the Ubiquiti Dream Router and not another AP, which might be further away? This shouldn't happen but you never know. (I don't have any Ring products so can't comment on those.)

@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.

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).

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.

Hi @Simon R, great post. Thanks for posting. A splendid to hear @Jeremy Harris being mentioned. You mentioned the site "wood online". I tried Googling it but came up blank. Do you have a URL for it?

Interesting discussion. Playing devils advocate, @PeterW, the reason you might buy a spool of cable and terminate it oneself is because Cable Money only sell a range of lengths (3, 5, 10, 20m, etc.) and, with decent gear, terminating is actually quite easy. What say you? (This is relevant for me is I will be running my ethernet network soon-ish in my new build.)

Slightly off topic but somewhat related is the matter of the reclamation of VAT under the government's "VAT DIY Scheme". If the property is deemed by HMRC to be being built for profit, I believe that the ability to reclaim VAT under the above scheme is also lost.

One subtle point of difference, @puntloos, for you to consider (and maybe ask MHRC about if you are calling them). I am under the impression that the 2-years mentioned is just a useful rule-of-thumb. The real underlying principle is whether the new property being built to make a profit or not. The 2-year figure is a time interval that can often demonstrate that, at the time of building the property, there wasn't an intention to sell it to make a profit. However it is the underlying principle that matters and not the time interval as such. Two examples that illustrates the point. 1) A self builder builds a house for themselves without any intention to sell. Life changes, such as a change in job location, mean that they sell it the moment it is finished and move with their job while making a profit. I think that it would probably be easy to convince HMRC that this was their PPR with no CGT to pay. 2) A self builder builds a house, lives in it for two years and sells it for a profit. They tell HMRC that its their PPR so no CGT to pay. Self builder then does the same thing subsequently three times in a row. Would HMRC then make the case that the self builder is actually a developer building houses for profit. I think they might. Would back taxes become liable, I don't know.

Yes, I see what you mean. Perhaps they are the same item, and with that part number it is for Vaillant's gas boilers. Or perhaps they used the wrong stock photo on the internet page. At just £5 it could certainly be worth a try!

Hey @Dan F, you could get your multimeter out and test the resistance of your one for us. You could sell the information to each of us for £250 a head and we'd all still make a profit after we've spent less than a £1 on materials 😄 (Joking).

Those light fittings looks splendid. Dimmable too. I see some have drivers built-in but others require an external driver. I am interesting in a driver that can be connected to HomeKit. I wonder if they can be driven by, for example, IKEA's LED TRADFRI driver. https://www.ikea.com/gb/en/p/tradfri-driver-for-wireless-control-grey-60342656/

Thanks @john0wingnut, I hadn't heard of NIBE. Had a quick look. I see they do a 6kW model using R410A. Is that the model you have?

Thanks Dan. Speaking to Midsummer about paying £300 for a resistor that costs pennies, they initially suggested an R32 Samsung unit instead, which has cooling enabled straight from the box. But Samsung's equivalent of the UnitTower (called Climatehub (!) is pricier so all-in-all there was not much saving to be had. And the Samsung heat pump is noisier too. Given the saving on the resistor I checked heima24 for the price of the Arotherm Plus itself and UniTower. I would have no qualms about importing it from Germany rather than locally within rip-off-Britain. To my surprise, the German list price was rather more than my UK quotes.

Good point. Here's an example from Belgium: https://lbge.be/product/vaillant-codeerstekker-voor-activatie-van-de-koelfunctie-0020269259/, €51

From the "£300" quote was from the wholesaler, Midsummer Wholesale in this case. The only seller I found was this one, £391.20 inc. VAT. https://www.heatingandbathrooms.com/coding-plug-cooling-function If only we could find the Ω-rating, I bet you could buy one for pennies and solder it oneself.

About the cooling resistor for the Vaillant Arotherm ASHP … I just contacted the company who will supply the ASHP and they said "Yes you need a coding resistor for cooling function. It's pretty pricey. About £300 from memory." Anybody know of a cheaper solution? Or did anyone buy it with the resistor already fitted? This video shows the resistor fitting, which, other than the protracted checking-for-a-gas-leak, seem to take about 2 seconds.

Does that require the optional Vaillant RH sensor I wonder?

I will be having ASHP cooling with my UFH for my bungalow. I think in reality it can only reduce the temperature by, say, 5º – 6º or so, so helpful but not a panacea. Worth watching this. Unconventionally, they succeeded in cooling their ankles.

Thanks @nod. Makes sense. Sounds like you don't use GA3 or GA4 Steel Angle on your projects. Am I right? Another question if I may: for openings over 1.2m, do you cloak the side studs with deep channel? And do you form the head beam from extra-deep channel with a stud attached inside?

@nod, another MF question for you if I may. How do you line an MF wall with 18mm OSB? What do you use as the supports attached to the studs? Do you use a combination of GA3 and GA4 Steel Angle or something else? My MF supplier can only order GA3 in packs of 10x, which is rather more than I need, so I am wondering if there is an alternative ingenious way of lining with OSB. (I note that there are the "Service Support Plates", in packs of 100, but they seem designed for one-off small pattresses, for sockets, etc., rather than lining a full wall.)

Interestingly, if read the manual correctly, the weight of Propane contained in the ASHP is just 0.9kg, which is rather smaller than the smallest usual gas cylinder (see below). And which, in liquid form, would, if my conversion is correct, would be just under 2 litre and so might fit in your kettle. This in turn would evaporate to form 520 litres of gaseous propane.

This will give you a flavour, at least for the AroTherm Plus model: Operational clearances: Propane related fire-risk clearances, especially from drains:

Boundary disputes are very tricky. Having just come out of one myself, I agree with the most common piece of advice. Seek an amicable solution with your neighbour without involving specialists or lawyers. On what basis are you asserting your interpretation of the position of the boundary line? A fence should always be completely upon the land of the person installing it (technically even including the concrete around the base of the fence posts). As said, there is nothing whatsoever to stop you erecting another fence entirely or your land adjacent to it.