Jeremy Harris

Disinfection is pretty easy. Just warn everyone in the house that the water is not going to be usable for a few hours, for anything. Pour a small (around 1 litre) bottle of unscented and unthickened bleach (usually the cheapest stuff from the supermarket) into the tank (having removed all the squirrel debris). Let the tank fill and leave it full of concentrated bleach solution for around half an hour. Then go around systematically opening all the taps fed from this tank taps one at a time until you can smell bleach at the tap, then turn the tap off. Finally flush all the toilets twice, to make sure the cisterns have filled with chlorinated water (assuming the cisterns are also run from this tank). Leave the system like this for half an hour to be ultra safe, then open every outlet and flush every toilet until you can no longer smell any bleach coming out. That's a real overkill disinfection process, but you will be assured that there are no living organisms anywhere in the pipe work. Chlorine shock works, it's the same stuff, but has the big disadvantage of taking ages to dissolve and get flushed out, as it raises the pH and stops dissolving, so needs a great deal more flushing out.

I have a lot of ducts that all come up in one corner of the slab. SOme are used, two are spare, but all of them are capped off with a ball of chicken wire stuffed down them, with a stout bit of wire attached to be able to pull it out and then some foam squirted in. The foam was cut level around the wire when it had cured and some airtightness tape added. If I need to get something else in, the it's a matter of unplugging the duct, running the new cable, pipe or whatever in and then sealing it up again. The ball of chicken wire (or expanded metal) does two things. It acts as a rodent barrier, to stop them getting at the foam and chewing it, and with the wire anchored to it it acts as a way to pull the plug out, complete with the foam. I've already had to pull one out, and I found that expanding foam doesn't stick that well to the inside of smooth ducts.

Hit the nail on the head there, I think. There's a cultural clash between software developers, who are quite used to a production model where something is released to the market and the customers find bugs that they then fix, and the car (or pretty much anything else) market where consumers expect goods to be completely free of faults. Sadly we have got very used to all software having bugs, as we've had decades where just about every bit of IT kit ever sold has had bugs in from new. We put up with PCs that periodically crash or lock up, that are vulnerable to attack, and that require us to go through the time-consuming process of "updating (which is 99.99% of the time fixing faults that should never have been there in the first place). We would never put up with something like a car that behaved like this, yet now we have a melding of the two technology areas where it seems very likely that we will just have to accept that cars are just like PCs. I think mine is now on it's third or fourth software update in three and a half years, and in reality those software updates were fixing faults and vulnerabilities in the code that controls functions within the car (not once has Toyota ever revealed what any of the software updates have actually changed, though!).

COP barely changes with temperature, as long as the air is dry. What seems to kill the COP is humidity - damp air condenses out and ices up the evaporator. Our Carrier ASHP (exactly the same unit is badged Kingspan and Glowworm, and probably a few other brands too) has a humidity and temperature sensor mounted right on the rear of the unit, that senses the air flowing in to the evaporator. The temperature and humidity can both be displayed on the Command Unit. From what I've been able to work out, from reverse engineering and experiments, the unit doesn't directly detect when ice has formed on the evaporator, but instead determines when the risk of this is high, by a combination of comparing the evaporator temperature (which is measured by an internal sensor in the refrigerant loop), the outside air temperature and the relative humidity of the air flowing into the evaporator, the logic within the unit tries to predict when icing is likely and uses that to trigger a defrost cycle. The defrost cycle has a greater impact on the true COP than might at first be thought, as I have a sensor half way up our buffer tank and when the ASHP goes to defrost mode it rapidly draws heat from the buffer over the ten minutes of so the cycle takes. The way it works is that the 4 way valve operates and the ASHP goes into cooling mode, drawing heat from the house and using it to heat up what was the evaporator heat exchanger (but is now the condenser) in order to melt any ice. So, when measuring the electricity drawn by the ASHP (I have a separate DIN rail mounted energy meter on the supply to ours) you also have to try and estimate the amount of heat energy that's been drawn from the house, and add that to the total defrost energy use, as clearly the ASHP has to work to replenish the heat it has pumped out of the house when it returns to normal operation. I've mentioned this before, but the worst case conditions seem to be when the outside air temperature is cold and damp. Cold, misty, weather seems to cause our unit to defrost if it's asked to deliver a high flow temperature, but cold dry weather (like a cold and frosty morning) won't make the unit defrost at all. I ran ours at 50 deg C when the Command Unit display was showing a very low RH on a cold and frosty day and it didn't defrost, which suggests that there is some pseudo-intelligence built in, at least to these models.

Heat pump sales people are very fond of ignoring the laws of physics, sadly, not helped by the official test conditions being related to temperature only, not humidity, and it's humidity that REALLY hits performance hard. The specs for our ASHP show that it has a high COP when delivery a flow temperature of 50 deg C, but read the small print and you find that was done in dry air conditions and the impact of defrost cycling was ignored. Realistically, I've found out, by trial and error, that keeping the flow temperature down around 40 deg C means the heat pump never needs to defrost, at least in our installation, and always seems to run at a COP above 3, sometimes over 4. As Dave says, an efficient condensing boiler may well be a better option for you, cheaper capital outlay and reduced running costs over an older non-condensing, or only partially condensing, boiler. Also, a condensing boiler run at 50 deg C will be very efficient, they stop condensing at around 56 deg C usually, so lowering the flow temperature just that little bit can make a very significant improvement to performance (there's a big efficiency boost as soon as the boiler is running in fully condensing mode).

The first point is that 50 deg C from an ASHP is going to hit the COP and take it well below 3, probably down below 2 or even below 1 on a damp, cool day. The COP will vary a great deal, depending mainly on two factors, the flow temperature being demanded and the relative humidity outside. Outside air temperature has a relatively small effect. The COP when an ASHP is run at a high flow temperature, like 50 deg C, will be dominated by icing and defrost cycles, something that do not feature in the official COP figures. On a day when the temperature is down around 4 to 6 deg C and the air contains a lot of water vapour (cold and foggy/misty days, for example) the ASHP will probably have to defrost two or three times an hour, for around 10 minutes each time. Every time it defrosts it runs in reverse, taking heat out of the house to warm up the heat exchanger to melt the ice that's formed. Clearly there is a negative COP during defrost cycles, plus a loss of operating time, which further reduces the net COP. The best solution at the moment if you already have an LPG installation, is to look at using a hybrid heat pump. These work by running all the heating using the heat pump, with a high COP because the heating flow temperature can be reduced right down, as long as you have UFH or over-sized radiators. The ASHP will easily run at a COP of over 3 all the time when run like this. When you need hot water, a hybrid ASHP will take some of the preheated water (normally at around 35 to 40 deg C) and instantly boost it to 50 to 55 deg C to use for showers, baths, etc. This dramatically reduces the gas consumption, as LPG is inly being used on demand, when hot water is needed. It also means that the ASHP never needs to try and deliver a high flow temperature so doesn't ice up and need to defrost. Daikin are probably the best known hybrids, with the Altherma range, but there are others. Finally, the COP divided into the unit electricity price does give you the running cost per kWh. In your case, with a COP of 3 and a unit price of 13.3p, you would be paying around 4.43p per kWh for heat from the ASHP.

Every keystroke or mouse/scroll movement is recorded by the site and sent back to a third party, for all the time that you have that site open in your browser. Apparently loads of companies are doing it now, in order to see how users interact with their site. They can replay any user's exact actions when they visited the website. There is more here: http://www.bbc.co.uk/news/technology-42065650 There are ways around this, I'm sure. The data is probably sent directly to the third party servers, so knowing those you could block them. You can do this in the hosts file (just redirects requests back to your local machine - a sort of oozlum bird trick) or better, add the IP addresses to a black list in your router. I do the latter, and periodically add new servers as they are picked up by those who sniff for these things, and have added a few that I've found just by looking at Wire Shark logs (Wire Shark is a packet sniffer that tells you who your machine is connecting to all the time - the first time you use it you may get a few surprises at the hundreds of servers your machine will connect to over the space of an hour or two.

I doubt that it's very secure at all. Making any internet connection secure to any reasonably degree costs far more than someone like a car manufacturer is going to fork out. I well remember the cost, and lead time, of the hardware encryption units we had to install in our two interlinked, but 40 mile apart, data centres. There were the single most expensive single component, just to allow TS data to be synchronised between the two data centres using internet connectivity. Previously, we'd kept all our secure data systems physically isolated (often behind several feet of concrete and steel) from any possible outside world connection. One of our old IT managers party tricks was to show how vulnerable ordinary kit was. I remember him just turning on the mic on the iPhone of a member of staff to listen in to what was going on, it took him seconds to do and the user was none the wiser. Not illegal, either, as the member of staff wasn't supposed to have his phone with him anyway, he should have put it away in his locker at the entrance. Anyone can hack pretty much anything unless is has really good security, and even good security isn't impossible to hack, it just takes more time and effort, The question here is whether the reward is worth the effort. In the case of keyless entry cars the reward has been worth the effort, as they are now stolen very regularly, using boosters to spoof the car into thinking the key is present nearby. Tesla's have been well and truly hacked, but that's mainly because a lot of Tesla owners are interested in finding out how the car works and what data it sends back to Tesla all the time. I dare say the autopilot could be hacked, the question really has to be is it worth the effort, yet? The answer now is probably that it's not, but no doubt it will be if the cars become popular. Data theft or leakage goes on all the time, on a massive scale, as things like phones, tablets, PCs etc are inherently pretty insecure. Google have just been wrapped over the knuckles for collecting location data from millions of users, even with location services turned off by the user, as knowing where people are is worth a lot of money to some people. Uber had just had millions of records hacked. Only today, it was revealed that anyone who reads the Telegraph online (or anyone one of over 400 other websites) has been having every single key stroke, or mouse or finger scroll movement, sent back to a third party, who analyses what you are doing, and collects everything you do when on that website. There is no such thing as privacy, and precious little security, in most consumer stuff, it seems that it is really up to consumers to educate themselves about the risks and take action themselves if they don't feel comfortable with the way some commercial products work.

I think a lot of us do it. Look at my heating system control saga as a classic example............

As an aside, and possibly off at a tangent, I have a few hard-one points to make with regard to CH control and sensing. The first is that, if you are naturally drawn to a technological solution, for the fun of designing, programming it and building it then it's a fun thing to do. You will spend a lot of time deciding on kit to use, fitting sensors and writing code to make the whole lot work. All told it's fun, and it's how I initially envisaged making our system. I don't regret the time spent doing this, but it was pretty time consuming, as first I had to try and model the house response under various conditions, then work out a control system that would work. The killer for me was time, both the time spent developing the code, but more importantly, the time take for the house to respond to any change. What started out as a slightly morbid thought, induced by my frame of mind at the time, came to dominate my thinking. I realised that if I wasn't around, there was no one who could just step in to maintain or repair things. That revelation caused a step change in my thinking. I cant rely on home brew software, short life cycle hardware and interface obsolescence (all those with phone operated controls probably face a complete system change in less than five years). I traded my natural enthusiasm for designing, building and developing stuff to only applying it to monitoring stuff. That's been invaluable in fine tuning an off-the -shelf control system, and that just about satisfies my desire to design something novel.

Sounds like a plan.................

I designed in a services room, accessed by a full sized (wide) oak door from the spare bedroom. It houses the MVHR, water softener, Sunamp PV, water filter and disinfection unit as well as the MVHR. All the external antenna cables come in via the top corner of this room (four satellite feeds, a DAB feed plus a spare feed), the antenna distribution box is in there, as well as the consumer unit, generation meter, house energy usage electricity meter GPS derived real time master clock and the house data logger (logs all the sensor data to a USB stick every six months, in 1 month chunks) is in there, with some spare network cable points and a bank of spare power points for future expansion. It's also a cupboard for cleaning stuff and a cordless vacuum cleaner, and has storage for salt bocks, spare water filters and MVHR filters. I even carpeted it a couple of weeks ago! Being able to just walk into a carpeted space, which has a PIR operated light that comes on as you enter, and do things like add salt to the softener, change the MVHR filters or get data from the house logger, is very useful.

Looks like the vertical pressure vessel that's in use is a 100 litre one, so about 50 litres of usable pressurised water between the pump stop and start points. Not sure what the glass fibre wound tank is. These are usually used as filter tanks, but there's no backwash valve, so I'm wondering if maybe you have fairly acidic water (common up where you are, from the granite) and that pressure vessel is filled with calcite chips to increase the pH? The filter is a standard (not jumbo) 20" one, probably with a wound filter to trap crud. I can't see the carbon filter, unless that glass fibre wound pressure vessel is filled with granulated carbon. That's a bit unusual, but not a bad way to make a high volume activated carbon filter, if that's what it is. The pressure switch is one of the spring ones, adjusted with internal screws. If you wanted to shift things around as an experiment, then It doesn't look too hard to re-jig things. I'd be inclined to start by removing all the disconnected/unused stuff, like that booster pump set (which I think was used to increase the output from the previous submersible pip, perhaps). and any unused pipe work. Then you have two choices. As the existing pump pressure switch is set to 4 bar, and is wired in and working, then you could look at just taking out the pressure vessel and filters, and directly connecting the pipework to the outlet pipe. Relocate the pressure vessel and filters to the upper pump house, and connect them to the supply from the pump and to the house. The pressure vessel will need to have it's pre-charge changed, so whilst it is empty, check the air pressure. A standard car tyre pump, or even a bicycle track pump (I use the latter) will do the job of checking and pumping up the pre-charge. The pressure vessel will be 10m higher, so will now be running ~ 1 bar lower in pressure. The rule of thumb is to set the pre-charge pressure to about 0.1 to 0.15 bar below the pump set cut in pressure at the tank (not the pump). So, if your pressure switch is set to cut in at 3 bar, that will be 2 bar at the pressure vessel when mounted 10m further up the hill. The pre-charge pressure will therefore need to be set to about 1.85 to 1.9 bar with the air pump, when the tank is empty. The advantage of having the pressure vessel closer to the house is that the losses will be lower, but I think you my well find that the 20" standard filter is causing a bit of loss. Best to do one thing at a time though, and minimise the cost of doing things, until you see first hand what effect the changes have. One things that is very useful is to have a pressure gauge directly connected to the pressure vessel and watch that when a tap is turned on. It should drop dramatically, down to 1 bar or less. If it doesn't drop much, then that is pretty much proof that the restriction is somewhere between the pressure vessel and the opened tap. Could be the filter, or could be the pipe work, but either way by moving the pressure tank you've reinforced the supply at the house a fair bit.

Very good point indeed, @dogman. Tanks can and do lose pre-charge, especially if fitted with plastic dust caps. It's a little known fact that the original Schrader valve (as used on tyres and pressure vessels) was never intended to be the primary air seal, it was designed to allow easy filling, with a leakage rate low enough to allow the sealing cap to be fitted before any appreciable pressure drop had occurred. Sadly, the majority of plastic "dust caps" provide no sealing at all, so I make a point of replacing them with proper nickel plated brass seal caps, that have a nitrile rubber seal in. This massively reduces the pressure loss from both pressure vessels and car tyres.

It's pretty easy to build one, Ian. If a bunch of highly disorganised young cavers can build one in a weekend, out of materials that were mainly scavenged from within 100 yds of the clubhouse, and with none of them having a clue as to how to lay bricks, mix mortar etc (I'd say 90% of the club members were either students or science/engineering graduates, with few building skills) and get it to work pretty much first time (the only mod was adding the galvanised steel milk crate) then I'd say anyone can do it. Bear in mind that it helps if you can cool down the trap, so that the water content sinks and the fat and oils float more quickly. I personally reckon a brick or block built one, or one just made up from fairly cheap concrete rings, would outperform a plastic one, and be tougher and better able to take a bit of abuse if it did get really clogged up. 600 x 450 concrete chamber rings are around £20 each if you don't fancy a bit of brickwork. Making a trap with these would be a doddle, just dig a rectangular hole, pour a concrete slab in the base, drop three or four rings in, drill pipe holes for the inlet and outlet and pour concrete around them to hold them together. Fit the pipes, make up a catch basket (go scrounging for something that will fit) and top it off with a standard drain cover and the job's done.

Probably a better choice than the ones I used. Mine are inside the pump house, so don't (hopefully!) get wet, and I only chose them because I already had an extension lead for my power washer that used them, so I knew they existed.

I know EXACTLY how hard it is to get good and reliable information on borehole and well systems here in the UK, as I really struggled with ours. I found that every single company that I spoke with, or used, except one, had some degree on incompetence, despite being supposedly experts. The one exception was a borehole guy who came out on site, had a very good look at what we needed, and what the hydrogeologist had recommended, chatted for about an hour or so and then was honest enough to say that really his expertise was mainly with boreholes in chalk, not gault and greensand and that although he'd be willing to have a go, he didn't think it was fair on us to use him when he lacked experience of drilling in this particular type of ground. We had endless problems with our borehole; the whole saga is in our blog, in several entries, but this will give a flavour of some of it: http://www.mayfly.eu/2015/08/part-thirty-seven-a-long-tale-about-water-and-life/ The treatment system design changed a fair bit after that, but that article probably highlights why I spent a lot of time learning about boreholes, drilling, pumps, water treatment etc! If you can take some photos then that would help a great deal. Most borehole stuff is made in Italy or Poland, with the very best pumps being made in Denmark, but they are expensive. Our Grundfos SQ 1-65 pump cost well over £600, which is a great deal more than the pretty decent IBO Polish borehole pumps that can be had for around £120 or so. As a near-zero cost experiment, you could, perhaps, just temporarily relocate the pressure vessel and filtration you have from down at the lower pump house to the upper one, replace the pump pressure switch with the one I suggested (you don't have to do this, but the optical ones are really nice and easy to adjust, and well worth the £20 cost!). You will also need to fit a non return valve down at the lower pump house, just as a backup, but for an experiment you can do without, as it's only really there to take the load off the pump intake valve, which may or may not be designed to take a continuous high back pressure (some are some aren't - our Polish pump definitely needs a non return valve on the outlet, the Grundfos definitely doesn't). The pipe lay out, from the bottom up, would then be: Pump riser pipe from the borehole to the surface (hopefully coming through a sanitary borehole cap, with screened breather vent) Optional non-return valve Tee piece with a 1/4" BSP female thread in the side port, for the pressure switch/gauge Optional drain cock Optional second non-return valve for servicing purposes only (see ** below) Pipe run up to upper pump house Pressure vessel installed in upper pump house, with a tee to the pipe feeding the filters. The filtration system you have (presumably a couple of jumbos - if they are not jumbos then you may want to think about changing them - see **** below for the difference). Output of filtration across to the house mains feed. When setting this up, to allow for the ~1 bar head loss between the house and the lower pump house, the pressure switch needs to be set 1 bar higher than the pressure at the house. I would advise setting the cut in pressure to 3 bar and the cut out pressure to 4 bar. That will then give you a range of 2 bar to 3 bar at the house, which is a reasonably good range of working pressure to have, and should give you a decent flow rate. One issue with the pressure switch is that it comes pre-fitted with two short 3 core cables. This makes installing it awkward, as they are rarely long enough to connect to whatever termination boxes you have (one for the pump switched power feed, on for the incoming power supply). My solution was to buy two pairs of these: https://www.tlc-direct.co.uk/Products/TLRC3.html fitted so that the plug is on the incoming power cable of the switch, and the socket on the outgoing feed to the pump, with suitable cables connecting another socket to the mains feed (make sure the power is isolated and checked to be dead before doing this) and a plug to the cable from the pump. This then makes life easier, as you can fit and tighten the gauge/pressure switch to the tee, then just plug the connections together. It's foolproof, as the connections will only go one way. Additionally, if you want to just quickly test the pump without the pressure switch (not recommended unless the pipe is open to flow water somewhere) then you can directly connect the pump cable to the power cable and switch on the isolating switch to check that the pump runs OK. As I mentioned above, this system also makes it easier to change the pressure switch if it ever fails, too. ** The idea here is to allow the short length of pipe between the second non-return valve and the first non-return valve (or direct to the pump) easy to drain down, without a flood. What this means is that you can turn off the power to the pump, open the drain valve to empty that short length of pipe, and change the pressure switch, or haul up the pump to change that, whilst the house still has a small reserve of pressurised water from the pressure vessel. It's a convenience feature, really, but for the relatively low cost of a drain valve and non-return valve worth it, IMHO, although I have to add that my view is coloured by having drained our system a couple of dozen times when I was battling to get it to work properly! **** The difference between standard 10" filters, long 20" filters and jumbo filters is very significant, both in terms of flow rate and filter longevity. Jumbos have a much lower pressure loss, and a greater filtration capacity and are just as easy to change. Here are photos that show what each looks like: These are the long and short jumbo housings, the canister part is around 140mm in diameter. They come in either 10" or 20" lengths, like the standard smaller filters. This is a standard 10" filter housing, it's around 90mm in diameter. This is a standard 20" filter housing. It's the same diameter as the 10" one, just twice as long. It doesn't have a significantly greater flow rate than the 10" standard filter, as it's quite restricted by the size of the head, but it does have around double the filtration life, from the bigger filter cartridge. We have two standard (10" high) jumbo filters. One is a 5µ pleated washable filter, the other is a carbon block filter. I've found that there's no noticeable pressure drop at all across these two filters, whereas when we had two standard 10" filters the pressure would noticeable drop when a couple of taps were opened at the same time. Hope the above helps, Jeremy

That's useful, so you're losing at least 1 bar of head between the lower pump house and the house ground floor, perhaps 1.5 bar or so at the first floor of the house. The borehole is about the same depth as ours (ours is 53m) but what matters is how deep the water surface level is below the ground, as that determines how hard the pump has to work. In our borehole the water surface varies from between 4.5m below ground level to about 11m below ground level after I've had the pump on continuously at around 30 litres per minute, for a couple of days, to clean the borehole out. I have a beep tester (easy to make) that I periodically lower down the borehole to check the water depth, and every time I've checked it's been around 4.5 to 5m down. I don't bother checking now, as I'm pretty confident that the water level is always stable at around that depth. I did allow for it dropping to 11m below the surface when sizing things, just in case. If you can relocate the pressure vessel nearer the house, and adjust the pressure switch to get around 3 bar at the house ground floor level, then that should give you a fair bit better flow. I suspect the variation you may have seen has been a combination of filters getting clogged and maybe the pressure switch being adjusted for around 3 bar cut off down at the pump house. If the pressure at the pump house was adjusted up to around 4 bar cut off (raising the cut in pressure to suit) then that would give you 3 bar at the house, which is a pretty reasonable pressure. It's not too hard to set a basic system up, but it depends what you want to do, and how old the existing equipment is. You mention that the pressure vessel is horizontal, which isn't ideal, but is a configuration that is often used for low capacity combined pump sets. These rarely have a very large pressure vessel, usually around 50 to 100 litres (so about half that in terms of stored water under pressure) and often have a pump mounted on top. If the water level in the borehole is not far down (less than about 6m) then one of these pump sets will suck the water up from that depth, so there's nothing more than a suction pipe going down the borehole. Sometimes, a pressure set like this can be configured as a jet pump (a very common set up in the USA) where the surface mounted pump is manually primed when first installed, and has two pipes going down the borehole. One delivers a low volume, high pressure, supply to the jet pump, the other is the outlet from the jet pump. Jet pumps are eductors, with no moving parts, which is one reason that have been popular, but they aren't very efficient, and will rarely deliver a very high pressure and flow rate. Nowadays it wouldn't be usual to fit a set up like this, with a jet pump, as there are plenty of reasonably priced and reliable submersible pumps around. If you have one of these then the give away will be a cable going down the borehole alongside the pipe that delivers water, plus (I hope!) a safety rope to prevent the pump falling down the borehole (it does happen.........). If it were me, and I wanted a more stable supply at the house with a better flow rate, then I'd look at fitting a pressure vessel of around 300 to 500 litres capacity at the house end, perhaps in the old pump house. I'd also fit the filters at this end, too, after the pressure vessel and before the house supply. At the borehole end I'd fit a non-return valve (in case the pump one fails - they do, and it then causes the pipe to drain back slowly) and then an optical pressure switch. I've found a very affordable Chinese made unit is very good indeed. It has a pressure gauge, with two movable pointers that are set by screws to the cut out and cut in pressure. They are so cheap that I bought two, and fitted them with three pin plugs and sockets (the ones used for extension leads for garden tools) so that I can quickly change them over if I ever get a fault. They are sold via Ebay, and these are the ones I have: http://www.ebay.co.uk/itm/151020-Automatic-Water-Pump-Pressure-Controller-Electronic-Adjustable-Switch/272751286212?epid=703592864&hash=item3f813e57c4:g:GCIAAOSwRvdZZOae They have a standard 1/4" BSP male threaded port at the bottom, with an O ring seal, so are easy to fit in place of the spring controlled ones. They also have the advantage that they don't freeze up in cold weather, unlike the spring ones.

It sounds to me as if you may well have some pipe losses that are contributing to your low flow rate. 150m of pipe running up a hill is going to reduce the flow rate, especially if the pipe isn't that big. Do you know how far down the water level is in the borehole, and how much height difference there is from the pump house to the house? Normally the pressure switch (which in your case will probably be down at the pump house) will be set to a cut in and cut out pressure. I have ours set to cut in at 3.5 bar and cut out at 4 bar, as I like having as high a pressure as I can, but I can only do that as I have an optical pressure switch, that is easy to adjust. The mechanical ones with springs and screws (which is almost certainly what you will have) are a PITA to adjust properly, so are usually set to around 2 bar cut in and 3 bar cut off. If your pump house is around10m lower than the house you will lose 1 bar of pressure straight away, because of the static head. Borehole pumps vary a bit, but our, relatively small, Grundfos SQ 1-65, can deliver 20 litres per minute at a pump pressure of 6 bar, or 10 litres per minute at a pump pressure of about 8.4 bar. Our borehole water level is between 12m and 20m below the height of our shower (the water level varies a bit with pumping rate) so our pump head loss is around 1.2 to 2 bar. That means I could still have 20 litres per minute at the house shower level at a pressure of about 4 bar if I wanted to, though. This is a pretty small pump (less than 1 hp), too. Putting a pressure vessel high up, and setting the pressure switch to maintain that pressure vessel at around 3 bar (allowing for the head loss due to the height difference and the pipe flow resistance), should make a very big difference indeed. That 500 litre vessel you linked to is the same make as one of ours, but I didn't pay anything like that for the 300 litre version I bought. IIRC, it was much less, around £300 IIRC. A quick look around shows that there are cheaper options for a 500 litre tank, like this one: https://www.ebay.co.uk/itm/500-Litre-Maxivarem-LS-Vertical-Potable-Water-Expansion-Vessel-Special-Offer/162723999819?hash=item25e31b304b:g:5HQAAOSwI59Z7wO-

If they are heavy doors, then they do take a fair bit longer. I employed a joiner to fit the linings and hang our doors, as with solid oak linings and wide oak doors they were too heavy for me to think about fitting. He was on £180/day (no VAT) and fitted two doors and linings a day, including all the door furniture, with three ball bearing stainless hinges per door. He was a bit of a perfectionist, though, and not the fastest guy around - but we do have every single screw head lined up so they all match, vertical for the slotted screws and the crosses all exactly vertical and horizontal on the cross head screws............

Simply unbelievable. You have to seriously question the competence of this inspector, as this is really basic stuff that he's getting seriously wrong. If we have inspectors as poor as this then it's no wonder that some of our new build housing is in the state it's in.

They are both different makes, because I fitted one, then added another one a bit later, when I found out I needed more flow to backwash our filter, but they are all much of a muchness, TBH, with nothing much to choose between any of them. Most seem to be either Italian or Polish, and the only thing I checked was that spare EPDM bladders were available for them if they ever needed replacement (it's slightly cheaper to replace the bladder than replace the whole tank, but not much in it when you take into account the additional labour involved). My pressure vessels are all vertical, because generally vertical ones last a fair bit longer than horizontal ones, as the bladder doesn't end up rubbing on the bottom of the inside of the vessel every time it cycles. Out of interest, why are you limited to 12 litre/minute? Is that a borehole capacity limit, or for some other reason?

I run our borehole pump at around that flow rate, to prevent the pump from drawing up fine sand. To get the flow rate up in the house to a usable level (12 litre/minute is too low, IMHO), I have two 300 litre pressure vessels in the pump house, that each hold about 150 litres of water at a pressure of between 3.5 and 4 bar. That's a big enough buffer that we can draw 30 litres/minute plus off the system if need be, with little pressure drop (the pipework from the pressure vessels/filtration is all either 25mm MDPE or 22mm copper). I also have another 100 litre pressure vessel inside the house, right next to the "rising main", that holds about 50 litres of water at the same pressure, 3.5 to 4 bar. This just adds a bit of local pressure reinforcement for instant events, like someone turning a tap on, or flushing a toilet, when the shower is running. It means we have lots of usable water pressure all the time, even when a shower or bath is being run. BTW, I only used two 300 litre pressure vessels for space reasons, it was easier to fit two side by side than one bigger one.

The only comment I'd add about the two cheaper models, is that they don't have an easy way of getting the fat berg out. We added the old galvanised milk crate in the top simply to allow the block of fat to be lifted out in one lump. Before that, the trap had to be dug out at the top, which was a lot more faffing around. Anything that will stick into the fat and has a handle, or handles, to lift it out will do, so it should be easy enough to fabricate something from stout steel mesh to fit one of the cheaper ones. Make it of steel, as that way you can just stick it in a small fire to clean it off.

Seriously, a basket in the top of a chamber works very well. The keys are: 1. Only direct water with fats in to the trap - the slower the flow the better it will work. 2. Make the trap deep and big, so the flow rate is slow and there is time for the fat to rise to the top. 3. Fit some sort of grid in the top to hold and secure the fat for removal. 4. Always draw the clear effluent off from the bottom, where it will be fat-free.