Jeremy Harris

@MikeSharp01 is spot on. 99% of screws have nowhere near the shear strength of nails, and much more importantly they have a reduced core diameter that increases the bearing stress in the material they are screwed into, so decreases their ability to withstand shear loads by a lot. Unless a design specifically allows the use of screws for a particular application, then stick with the approved fasteners, which in this case would be twist nails.

The AAV is there to prevent a vacuum build up as a slug of waste and water goes down the foul drain. There's a risk that without it the partial vacuum in the pipe might cause the pan to back up as it refills after the flush.

I have a pretty old pneumatic first fix nail gun that never, ever jams. Stick frame builders in the USA seem to exclusively use pneumatic nailers for some reason, that's where mine originally came from. One the other hand, I noticed that the Paslode gas nailers that the guys fitting our cladding used needed to be cleaned every now and again and would periodically jam. My guess is this is down to the residue from gas combustion, a bit like the muck that builds up in a gun. All the pneumatic nailer needs is a drop of oil now and again and it just keep going.

Just checked, you can hire a positive placement nailer for around £70 a week. I think I'd opt to hire one rather than drive 17 twist nails in by hand on every hangar. You'd probably get them all in within a day using a PPN, and a day's hire would be less, around £40. I have a full complement of fingers on both hands, and I'd still opt to use a nail gun over driving nails by hand, any day.

Nothing to do with the gauge of the metal and everything to do with shear loads and the max allowable bearing stress around the fasteners. The limit is the bearing stress in the timber, not the bearing stress in the hanger holes, hence the large number of twist nails needed. Agreed, but if you have many hundreds of nails to hammer in it may be worth getting one, or hiring one.

Nail gun loaded with collated twist nails.

Done...

Adding to what @jack has said about the minimum volume, I can add that our UFH is very marginal in terms of meeting the (unspecified) minimum volume for our 7 kW ASHP and goes into anti-short cycle mode without a buffer tank. We have around 300m of UFH pipe in total, over ~75m² of floor area. The volume can be worked out fairly easily from the pipe length, as the 16mm OD UFH pipe has a volume that's near enough 0.1 litre per metre, so our 300m of pipe has a volume of around 30 litres. Because of this low volume we needed to add a small buffer tank of 70 litres, although I opted to use one with a high efficiency coil in so that I didn't have to use 100 litres of expensive antifreeze/inhibitor. The effect is the same, in that the ASHP effective "sees" a volume of 100 litres, but the actual volume of antifreeze/inhibitor in the ASHP and UFH circuit is only around 35 litres.

The council have an implied right of access under common law, the same right of access that allows the postman, delivery people etc to walk on to your property. Back when I caught a council snooper on CCTV climbing over our security fencing, walking around the site with no PPE on etc, I looked into this in detail. What I found is that you can remove the implied right of access for everyone except the utility companies and emergency services if you wish, just by giving notice. In my case I wrote to the council, recorded delivery, withdrawing the implied right of access for all council staff, contractors etc, until further notice. I backed this up with signs on the fencing: Notice removal of implied rights - blanked.pdf I removed my prohibition on access when we'd finished the build, so that bin men etc could do their job. I also specifically granted a right of access to LABC, for building inspections.

The only word of caution I'd give relates to the flooding of my late mother's farmhouse. To make it easier to reach the washer and drier she had a raised plinth built at the end of the kitchen, so they were a foot or so above the tiled floor. This worked very well, and saved her having to bend down. However, a few years after having done this, she put a load in the washing machine and went around to see the wife of the farmer "next door" (about half a mile away). She was gone a long time, and one of the suspension units for the drum failed. The machine must have started vibrating and shook itself forward until it fell, face down, on the floor, smashing the door. It went on to try and do a rinse/spin cycle, but the level sensor didn't shut off, as it was trying to fill the whole ground floor of the house. She came home to find the carpets floating off the floor and pretty much everything on the ground floor soaking wet. It took around 3 months to dry the place out, rip the plaster off the walls and re-plaster, replace most of her furniture and all the carpets, etc, during which she had to stay in a hotel - not the easiest place to run a farm from. The insurance company paid out for everything, but even so it was a heck of nuisance.

Just looking at the product range, it seems that there has been a gradual shift away from a focus on making more effective use of energy from domestic scale renewable generation and towards becoming a competitor for conventional hot water storage systems. I'll freely admit that I hadn't noticed this shift in emphasis in the time since we first fitted the Sunamp PV. I think that one issue may be that product R&D may be being spread a bit thin as a result of the many different variants being brought to market at the same time. Just from my personal observations, the old Sunamp PV was a better engineered and finished product than the newer UniQ; just a glance at the unit when it was first unpacked highlighted this. The eHW may well be able to be fine tuned to overcome the shortcoming in it not being able to utilise excess PV generation charging very effectively, I don't know. I hope that some further development of the Qontroller is able to overcome the present inability to accept charge until the unit is ~50% discharged. I have wondered if the designers may have just missed the need to be able to store charge for use further ahead than the next 12 hours. In winter, it's important to be able to store energy whenever it's available, so that it can be used 24 to 48 hours later, avoiding the need to use grid energy. Unless you've lived with PV for a while, and seen the high degree of generation variability during the winter months, then you may not realise how important this ability to maximise energy storage for later use is, if, say, the next day is cloudy.

They could just adapt the heater/pump/control assembly from the top of a Sunamp PV, as that works very well at charging the PCM58. There must be a few surplus Sunamp PV assemblies floating around in the factory and I can't see it being a major engineering challenge to reconfigure them, but the problem is that there probably isn't a significant market for such a unit.

I had three or four long phone conversations with them, and had a firm quote. Same goes for the borehole collector, I had a firm price from our borehole drilling company. So, the prices I quoted were real, firm, quotes from two companies, not some mythical estimate from a website.

Halfords batteries won't last a year in an off-grid home application, I'm afraid, as even their supposed "deep discharge" batteries have a really short cycle life, around 200 to 300 cycles is typical.. There are really only a couple of proven off-grid lead acid battery systems, and that's either to opt to fit Rolls wet batteries, as Paul Camilli uses, or to use forklift battery packs. Lots of off-grid people swear by fork lift packs, as they are often available at a reasonable price. The key to making them last seems to be to never run them below about 75% to 80% SoC, to always control the charge regime carefully to minimise gassing and to regularly keep them topped up. The need to never deeply discharge lead acid batteries, even fork lift or Rolls cells, means that the installed capacity has to be around five times the usable capacity. It's tough to get below about 5 kWh per day consumption when off grid, so that implies having around 25 kWh installed capacity as a bare minimum, more if you want to live with all modern comforts. A fork lift pack will anything from about 600 Ah to 1000 Ah at 48 V, so between 28.8 kWh and 48 kWh installed capacity, around 5.8 kWh to 9.6 kWh usable capacity, and cost somewhere between £2500 and £3500. With luck, and careful looking after, they should last ten years to fifteen years. One challenge with them is the weight and getting them to where you need to put them, as even the individual cells in a forklift pack are damned heavy to shift.

I priced up a Kensa GSHP installation back when we were still looking at options. The heat pump and installation kit was around £4.5k, the borehole, including collector piping was about another £5k and the antifreeze was around £400. There would have been around another £500 of ancillary stuff I expect. Opting to use a vertically trenched slinky collector was a lot cheaper, under £3k IIRC, but would have been problematic in terms of the impact it would have had on the foundations for our retaining wall. I think @jack's figures are about right for a GSHP/ASHP in terms of relative cost, and they certainly tally with the cost comparison I did.

They are usually just a push fit into the manifold, often with a bit of thermal grease around the end of the heat pipe.

Yes, it does, it's around 8 deg C in our case. I looked at two ways of using a borehole as a heat pump collector, as the additional cost of a second borehole purely as a collector was small - much of the cost in drilling is associated with the fixed costs of getting the rig and people on site, plus lining the hole etc, and a collector hole doesn't need lining, as it gets grouted when the pipes are down it anyway. If you want to pump water from a borehole and run it through a heat exchanger on a heat pump then there are a couple of issues. The first is that it takes a fair bit of power to pump water up from the borehole, far more than that needed to just circulate water through a closed pipe collector. The second issue is that the EA consider water pumped out of a borehole to be extraction, even if the water goes straight back down the same hole, and it's easy to exceed the 20,000 litres per day licence-free extraction limit. Overall, an open-loop system for extracting heat from borehole water doesn't seem that efficient, which is probably why borehole heat collectors tend to always be closed loop pipe systems.

Had a very comprehensive reply from First Direct. It seems that they are retaining all their present options for authenticating online banking transactions, which is good news. However, they have said that Visa are introducing mandatory SMS authorisation with a OTP for their "Secured by Visa" authentication system and there will be no alternative available - Visa are opting to only use mobile text messages for authorisation. This means that some debit or credit card payments made online may only work if you can get a mobile signal to receive the OTP text message. From this, I think it seems likely that the BBC story was driven by the actions of Visa, rather than anything else. At the moment, I seem to get a "secured by Visa" pop-up for about 20% of online card transactions, but the verification method is by fixed password. This will change soon so that the only way of verifying a Visa payment online will be via a OTP sent by text to a mobile phone. Apparently Visa are not yet offering any alternative verification system, according to First Direct.

We only used the pump for two or three weeks. It was a deep service trench right along our boundary that, amongst other things, had a DNO main power cable to go into it, feeding other properties. We were being dicked around by the DNO connection team, so had to keep the trench open until they finally got their act together. The trench was probably half a metre below the local water table, so every morning it would be half full of water, which we'd then have to pump out, as the water tended to make the sides of the trench fall in.

We looked for plots and development opportunities in Devon and Cornwall, and found that much of Cornwall is still damned expensive ( I lived there for years - my late mother's farm is down there). Devon is a mix, with South Devon being both expensive and having pretty restrictive planning regulations. The North Cornwall/Devon border area can be a bit cheaper, but, as above, you need to get up into North Devon for prices to get more sensible. There were a few places we looked at in North Cornwall that were affordable, but they tended to be in slightly odd areas. We found a nice plot overlooking the Tamar, near Calstock, and I have a cousin who lives in the town, but I think it's mandatory that you have an "alternative lifestyle" in order to live there...

I half buried an old bucket in one trench that we had to keep pumping out. I drilled holes around the top edge, just about the depth it was buried to, and added some lumps of crushed concrete in the bottom to hold it down. The pump sat on that, and effectively drained all the water from the trench. The only slight snag I found was that the float switch would sometimes get caught by the side of the bucket and not drop down enough to turn the pump off. Not really a problem if you keep an eye on it.

We had no choice but to pay the fee here, as the local authority demanded it be paid as a part of the process of getting the house on the council tax register. They made it clear that not paying wasn't an option, and that they would contest any house name we chose to use if we dared to try and register the address on the PAF database without going through their street naming team, who will only authorise certain house names (no house numbers in our village). Our main problem was that the listed address of the plot on the planning application was the wrong lane, wrong post code and named the house that used to own the land, so we couldn't carry on using that. I found that even paying the £120 fee didn't resolve the Royal Mail database problem permanently, and that not being on that data base is a PITA. I fixed our house dropping off the PAF database (for reasons I still don't understand) by using the link that @newhome has given, which worked a treat. The PITA aspect of not being on the Royal Mail database is that I found that insurance companies, the DVLA and banks all refused to process our address change when we sold our old house unless the address was listed on the PAF and could be found with an online check. Luckily, the database change using that link above was very quick, within 24 hours our address was coming up on insurance company and the DVLA sites. Quite important, especially the DVLA, as we were warned that failing to change address details on a driving licence attracts a hefty penalty. DVLA knew of the sale of our old house very quickly, and wrote to both of us warning that we must tell them our new address immediately and get our licences and vehicle registration details changed.

I've just posted the results from the first week of monitoring in this thread (click the arrow at the top right corner below to go directly to the post):

It's definitely possible and practical to be completely off-grid, but is far from being as maintenance-free as being on-grid and always needs a degree of tinkering to get a system set up and keep it working. One good source of info is Paul Camilli's blog: https://lifeattheendoftheroad.wordpress.com/ . He's been living off grid on Raasay for many years, and has pretty much got everything cracked when it comes to what works and what doesn't. He does have the advantage of a fair bit of wind, plus a constant low power hydro system, but IIRC he gets a fair bit of his energy from solar. I think you probably have to be a pretty practical sort of individual to keep everything running smoothly, as paying for someone to come out and fix things, look after batteries, do the maintenance on wind turbines, generators etc, would probably be both challenging and expensive. Having said that, my uncle's farm was off-grid until the mid 1960s, and had nothing more complex than a big Lister generator for power. That was started up when power was needed each day, then shut down in the evening, when oil lamps were used for light, but this was back before everyone had TVs and other stuff that needs to be powered.

Initially I just fitted a length of 40mm solvent weld waste pipe through the wall, fitted with a straight connector plus a screw on access plug, like this: https://www.screwfix.com/p/floplast-abs-access-plugs-white-40mm-5-pack/23322 poking out the front of the box, near the top. I bored a large hole in the access plug lid, and then screwed it back on with a disc of stainless gauze trapped between the rubber washer and the inside of the lid. The 40mm pipe just projected about an inch inside the housing, next to the pump, but there was a slight noise coming from it (not much, but we're in a very quiet area). I added a 90 degree elbow and a short length of pipe inside the housing, so that the open end of the pipe was pointing away from the pump, and this reduced the slight noise from the intake to virtually nothing. I have lined the walls and under the lid of the box with acoustic foam, the egg box stuff, and that tends to help absorb what little noise there is, too.