ProDave

My inclination is high impedance neutral, so the neutral is floating about all over the place, making one phase too high in voltage and another phase too low, depending on what loads are applied to each phase. Neutral faults are very common due to the abundant use of concentric cable. But you would have thought (hoped) the electrician would do a loop impedance test from each phase to N to confirm this. Also you would hope SSE's monitor is measuring each phase to neutral and logging it. If it is measuring phase to phase, then it would miss that fault. Get a basic multimeter and measure each phase voltage with respect to neutral. Also measure neutral voltage with respect to earth and report back. I had this once after a storm, SSE installed a mobile generator to a care home to get power back quickly and blew up half the stuff in the house because they habe neutral and a phase swapped over. When I called them out to show the problem, unbelievably the guy started the generator and waved a volt stick over each phase and said "what's the problem" I had to show him with my meter. They had a big bill for repairs, including several televisions, a computer and a new fire alarm system.

The space issue is taken care of in Scottish building regs. A minimum circulation space of 1400mm by 1800mm so in a galley kitchen you must leave at least 1400mm space which is ample for a conventional oven door.

Best of luck with that. I take it you personally will not be carrying the washer up the stairs?

Bedrooms are the place for a laundry basket, one per bedroom, that is where you get undressed. Having then to carry your clothes to another place to put them down the chute would then just be a PITA.

No that was 150mm of mineral wool type insulation. New house has 300mm

Yes the 600mm refers to the overall width. More important is finding one the right height to fit the gap in the unit. They come in several different heights, as do kitchen units, and sometimes spacer bars are used to make up the gap. It's a lot simpler buying the oven and unit from one supplier, in fact Howdens had a much better selection of Ovens than anyone else in the local area to us.

I have said this before, but there is nothing "new" in what this thermostat is doing. All it is doing is mimicking how a mechanical thermostat with an accelerator heater behaves. People shun them now as "old" and "inaccurate" but I am finding our new mechanical thermostat is working very well indeed. To overcome the inherent hysteresis with a mechanical thermostat, they have a small very low power accelerator heater that warms the local environment very slightly when the heating is on with the effect of cancelling out the hysteresis. A by product of this, whether by accident or design, is the modulate. As you approach the set temperature the thermostat turns off, then a short while later back on. As it gets closer to the set point the on duration reduces and the off duration increases. I think what I am saying is unless you actually want a programable capability (different temperatures at different times of day) then it is hard to beat the simple humble mechanical thermostat. At least everyone knows how to work one of those!!!!

You don't see people working outside in shorts and a tee shirt at this time of the year up here.

^^ For that reason, you should not put Propane cylinders next to a drain, and why gas bottle storage is such an issue on boats (where any gas leak will end up in the bilge)

So the message to anyone reading and about to do their plumbing is DO NOT put the ABV right in between two 90 degree bends. All seems to be working fine and silently now, both HW and heating working as they should. So I will leave it as it is.

What is of more concern to me is we used a total of 47KWh on heating and HW in the week, but the total used in the week was 130KWh so 83KWh on "stuff" so I am looking to find how we can reduce that.

I would love to know the back story. Is this a new house or was it fitted to an older house? Who paid for it and why was it ripped out in preference for a gas boiler just 4 months later?

You could be right. That is the flow and return both coming up out of the floor and 3/4 of the way up the cylinder to where the coil connections are. The ABV is connected between these just above the floor. Above that and to the right is the 2 port motorised valve for hot water The flow rate is relatively high at 15l/min so water is indeed more likely to go straight on, rather than make a 90 degree turn to pass through the (now nobbled) ABV. My guess is the noise was an unfortunate resonance thing, with the workings of the ABV oscillating at the resonant frequency of the coil and making it vibrate. No ill effects so I will see how it goes.

So I have finally got around to trying to investigate this. The one thing I wanted to eliminate before I contact the cylinder manufacturer, is the automatic bypass valve. This is situated in the airing cupboard between the flow and return pipes, immediately before the 2 port motorised valve for the cyilinder, this puts it as far from the heat pump as possible. Adjusting the ABV does not stop the cylinder noise, but it goes through a transition as you close the ABV down you momentarily get silence before the noise starts up again a few seconds later. It is impossible to find a setting where it remains silent. To replace the ABV is not easy, will need a bit of pipework stripped down (didn't think that through enough) so I pondered what I could do to eliminate it. Well what I have done, is remove the top of the ABV, remove it's spring and plunger and put it back together. So now it won't be operating as an ABV but as a permanent bypass and probably way too much bypass. The result. Totally silent hot water heating. Hot water still seems to heat up okay in spite of almost certainly too much bypass. I assume convection ensures enough flows through the heat input coil rather than all bypassing? No detrimental affect noticed on space heating. Even with too much bypass, the manifold pumps seem to ensure enough circulates through the UFH and it maintains it's temperature. What now? Leave it like that? Replace with a new (different make) ABV? replace with a gate valve to give manually adjusted fixed bypass?

If it's monoblock, then what is the "inside unit" looks like a split system to me. Why was it only used 4 months?

You seem to be missing a bit of the model number. It should end in ,A04 (3Kw) .A07 (5.6KW) .A10 (7.7Kw) or ,B10 (7.5Kw) https://translate.google.com/translate?hl=en&sl=de&u=https://www.energieheld.de/heizung/hersteller/viessmann/vitocal-222-s242-s&prev=search

It's a split system so will probably need re gassing.

12.5mm here. I never see anything else used except where 15mm fireline is specified (garages for instance) and then it's 2 layers of the stuff. Regarding strength though, I have noticed a difference recently. When I did the upstairs, it was "normal" plasterboard, as I had always known it. Easy to score and snap to cut to size. But all the stuff I have been getting for the downstairs (just ordered as normal PB) when you score and snap it, it is much tougher, and looking at the raw snapped edge, you can see hundreds of fine strands of fibre. I have never seen mention of this "reinforced" PB anywhere?

Well it has been exactly a week since the meter was installed so time to take a reading and analyse what has been used. Firstly Hot Water. My meter tells me I have used 23KWh in the week heating hot water. If I take a guestimate that it might be running at a COP of about 2.5 that equates to 57.5KWh of heat, or 8.2KWh of heat per day. Some of that will be loss from the HW cylinder (that will at this time of year add to space heating) Now space heating. My meter says we have used 24KWh heating the house. Again taking a guestimate at a COP of 3.5 that gives 84KWh of heat, or 12KWh of heat per day, or just taken as an average over the whole period equates to a constant heat input to the house of 500W At this point some of you (in the south still basking in summer temperatures) will be questioning why we need heating yet. Well it's been a long time since we had anything like "warm" up here, and for 2 or 3 weeks it has been averaging about 10 degrees, and the house had gradually cooled down to 18 degrees, so apart from anyhing I wanted to make sure the heating worked and was actually capable of heating the house. That heating usage seemed to be mostly in the first dew days as it was gently warming the house up again from 18 to 20 degrees. Now it is up to temperature, the heating does not come on often, so next weeks figures should be interesting and probably more relevant.

Wiring a plug is a "life skill" not taught any more.

I "fixed" a "boiler stuck on" fault the other day. It was the HW motorised valve seized. Removing the actuator and the controls worked and the boiler shut off correctly. Initially the valve was stuck solid but a pair of mole grips got it turning and after several full revolutions it was turning freely. Put the actuator back and it all worked fine. I did warn him if it seizes again he will need a plumber to replace the valve body. I wonder if it was just gummed up with carp and rotating it several times further than the actuator turned it cleared all the debris. for now.

B&B or guest house. I remember when building our last house and not long after we had moved up here, I met one of the community councilors. When he realised who I was, he said "Ah yours is the house with 5 toilets......"

So, devils advocate here, you are having an "all electric" well insulated house. How will you heat the house and hot water? What thought have you put into it so far?

My only comment is £10K for the mvhr. A casual viewer would discount that when desigining a house as an expensive luxury. Mine cost well under £2K Interesting the "solution" to a low VOC sofa, was buy an old one, so some previous owner has "suffered" it's ill effects.

Oh that's sneaky. Hadn't noticed that. but I am sure I have seen others at least including the inverter for £2K. Mine will be ground mounted probably on a home made mount (which will form a shed roof) so minimal cost there. Re payback times, a 4Kw[ system will generate something like 3100KWh per year. Even if you only use half that, it will reduce your electricity bill by 1550 units per year, which at 14p per KWh is a £217 saving. If you can get close to 100% usage, the saving will be getting close to £400 per year.