Ed Davies

Personally, I'm OK with 20% VAT on solar so long as they also charge 20% on other forms of domestic energy.

5.5p/kWh. Imagine somebody on a car forum not knowing the difference between miles per hour and miles.

Is there a better source than the Daily Mail? E.g., one worth clicking on?

For a modern house where the slab is no more than a few degrees (at most) warmer than the room and held at a steady temperature I can't see it making much difference whether there are pipes under the cabinets or not. As @Russell griffiths said, not putting them under just means the flow temperature needs to be a bit higher which might matter depending on how your loops are organized. I can see the point of not putting them under the fridge or pantry but wouldn't you need some sort of thermal break in the slab for that to make much difference?

Understandable, given your profile picture.

Yes, you will. A laser level is very handy for all sorts of things. Of course you can often use a spirit level for the same job but a laser is often easier and more accurate, particularly if you're on your own and things are awkward.

Ah, I'd have assumed that except for your previous comment: But, yes, good to have confirmed that 50mm pipe to the AAV is sufficient. I also suspect that a 50mm (or even smaller) vent pipe would be sufficient. My plan is 1) thin pipe venting the system by the treatment plant to get rid of any build-up of gasses (rainwater pipe?) and 2) and 50mm pipe from the nexus of pipes behind the bathroom up into the loft with an AAV there to prevent suction problems.

Where does it go from there? What's on the end of the pipe?

I've not taken much interest in RHI at all, but my understanding is that you need a heat meter if there are mixed sources of heat. E.g., heat pump plus wood boiler. So maybe the fact that your PV feeds heat into the DHW would mean that you'd theoretically need a heat meter.

Right, but back the “olden days” when people didn't have AAVs [¹] but just an SVP going up the outside of the house it would still have been cheaper and less unsightly to put a reducer above the highest connection (bathroom typically) then, say, 50mm up to somewhere above roof level. [¹] I.e., a significant proportion of existing UK housing.

That switch is clearly intended to go in a 19" rack. Its dimensions are 440x204x43 so approx 17.3" wide before adding ears for mounting (IIRC, 19" is the total width of the front panel/ears) and the standard unit of rack mount dimensions is 1.752" (44.5mm) so 1U with 1.5mm of wiggle room.

Aren't these two separate issues? My understanding is that somewhere in the system you need a vent pipe to stop gasses building up in the pipe work, i.e., higher pressure in the pipes so smelly gas pushes past the traps and gets out into the rooms but, separately, each vertical run of pipe needs somewhere near or at the top for air to get in to prevent suction behind a large blob of liquid/solid falling down the pipe, acting as a piston, resulting in low enough pressure that air from the room gurgles past the traps which is an irritating noise and, worse, can empty the trap. What I find odd is that SVPs are usually big (110mm?) despite their having to only vent a very slow evolution of gas whereas AAVs which could need to let quite a lot of air into the system in a few seconds are quite small. It seems to me that big SVPs are likely only a result of tradition from the days when the two functions were combined in a single vent pipe which both vented gas and allowed air in to prevent suction. Maybe also from when toilets used a larger quantity of water at each flush.

Stick the slips to whatever backing material is used, cut the whole lot, then crane it into place?

Yes.

In what way?

Something which could be tried to help keep a larder cool would be a thermosyphon to an external radiator higher up. That would act as a thermal diode so that heat went out but not in so that the larder would tend to track the average daily lows, rather than the average daily averages, IYSWIM. If the external radiator was facing the sky and protected from radiation from the surroundings it'd tend to track the night-time sky temperatures as well. I'm thinking of two radiators connected bottom-left in, top-right out (or whatever) in a loop full of water/glycol with just a little pressure vessel to deal with expansion/contraction. No pump or controls.

As in Highland? Are you near Beauly or am I thinking of somebody else?

As in bedrooms and bathrooms on the ground floor, living rooms on the first floor?

Maybe not applicable to @jamieled's situation but wouldn't an accumulator tank be better in a case like this as it'd preserve the pressure from the head of water from up the hill?

Water regulations don't apply to a private supply, anyway. BC and/or EH [¹] might impose similar conditions but they'll be happy with equivalent levels of safety, not insisting on to-the-letter compliance. Mine were quite happy with my proposed design for a rainwater supply once I accepted some labelling requirements from BC and made it clear to EH that I wouldn't be preparing food for the public, i.e., not running a B&B or anything like that. EH sent me a leaflet saying that I should provide 200 (IIRC) litres of water per person per day on the assumption that each bedroom was occupied by two people. I replied that, yes, I'd seen a document like that before but thought it was unreasonable as that isn't how the house is designed to be occupied and that 200 litres/peep/day was a lot more than needed. I referenced a Navitron forum thread about people's actual water usage with different levels of effort to reduce. They accepted that and asked if they could come to have a look at the system once it was installed, for their own education. [¹] Environmental Health.

I think that statement must be a result of some confusion somewhere along the line. It's a few years since I've been involved with this stuff but I have done mapping software working directly with OS [¹] people and data (in the late 1990s) and then (early 2000s) on more general geodetic software (for the aviation industry) where the partner company was a consultancy separately involved in the update to the British Grid Reference system. From the 1930s until about 2000 (I think it was) the OS grid was based on the Airy ellipsoid. The positions of various main trig points were determined (with sextants, etc) then other secondary trig points and actual points on the ground were derived by triangulation assuming a particular shape for the Earth (or, at least, the Earth's gravitational field). This was a pain because positions were not well defined with respect to GPS surveying which everybody used - things could be a metre or so out of position and the GB is moving, along with most of the rest of NW Europe, at a small but not completely insignificant rate (25 mm/year in a NE direction, IIRC) relative to the ITRF (International Terrestrial Reference Frame) which is linked to the WGS84 ellipsoid that GPS uses. Consequently, around 2000 the OS grid was redefined as being relative to the ETRF (European Terrestrial Reference Frame) which is a simple, but time dependent to allow for continental drift, transformation from ITRF. To allow for differences in the ellipsoids used and the errors in the old survey networks a separate correction is applied (OSTN - Ordnance Survey Transformation Network) to get the actual grid positions. It uses quite a big table to derive the correction for any given point as the errors involved are not uniform. I can believe that this has resulted in grid shifts of up to about 1 metre in some parts of the island, the old OS Grid was only defined to about that level of accuracy anyway. I very much doubt that there's been a systematic shift of 1 metre across the whole country. [¹] BTW, it's the Ordnance Survey, meaning guns, etc, not Ordinance Survey meaning by-laws. It was set up to provide the army with good maps of their own country for fighting Jacobites and potential invasions by Napoleon. What's usually referred to as the OS is for Great Britain only so doesn't interest itself in the “whole of the UK” - there is/was a separate OSNI.

Those with two dishwashers who follow the-use-from-one/put-away-in-the-other protocol, do you have some sort of flag to remind you which is which at any time? Should usually be obvious once you open the wrong one , I imagine, but still annoying. And there's potential for confusion when one dishwasher contains only a few apparently clean but not necessarily actually clean items.

I have a similar question to @jamieled: I've used TF200 on my walls (and around my window reveals). It's stood up nicely to long exposure, about 18 months for the oldest bits. Ideally, I'd like to use it to replace the failed stuff on my that failed when it got wet and froze. I can't see the point of a membrane which can't stand freezing when it's wet - the most likely conditions for a roof failure which results in water getting on to the membrane are freezing conditions resulting in ice damming or other such problems. Apart from anything else, TF200 is shiny which will improve the insulation qualities of the roof a bit. But TF200 isn't certified for roofs. Any idea why?

Does this video help? Youtube is excellent for working out most Velux stuff (compared with the Velux instructions which are not very helpful as a checklist once you know what to do and give no clue at all if you don't).

I wonder how much this is all botty covering. If there's a prominent fatal fire caused by arcing the immediate question will be: why aren't AFDDs mandated the way they are for bedrooms in the US and Canada? Because they're expensive. Money before lives? Outrage. Etc. So then the question is, why are they mandated in bits of North America? And do any valid arguments there apply here with twice the voltage and half the current?