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Wrap some 110mm pipe in tin foil and it'll look like stainless steel!

Well, you wont believe it! When presented with some additional information about the real-world ventilation (number of window trickle vents etc) building control have decided to let me away with it 🙂 RESULT!

Have you thought about getting 6 toddler outfits with welly boots, and putting a plastic bottle of red paint inside each one.. Hidden camera, easy £250

Well not really. Most people want the best figure they can get. Unless the OP told him before he started "I don't want any lower than 5.0" how would he know to do other than what he has been instructed to do?

Given we have UFH embedded in a passive slab with a huge mass, standard thermostatic control is not a feasible control approach given the large lag. A correctly configured weather compensation approach would be suitable (and this is what I use in the winter), but the Vaillant controller AFAIK doesn't use weather compensation for cooling. Given Vaillant doesn't support external "call for cooling" to date I've simply been manually controlling cooling in an attempt to keep a decent temperature in the summer. The issue with this approach is that slab temperature creeps up without you noticing and then it can take quite a while to get it back down. Now that I finally got my hands on an eBus adapter ( https://adapter.ebusd.eu/v5/) I can now think about putting in place a control strategy that will hopefully (once tuned) look after itself all summer! Keeping the slab temperature constant isn't enough, as depending on the outside temperature if it's a cool week the slab may need to be at 21.5C, but if it's a very hot week the slab may need to be at 20C to provide the necessary cooling power to cool the house. What I think I need to do is implement my own external weather compensation using the forecast average 24-hour exterior temperature in order to determine the necessary target slab temperature and then switch ASHP cooling externally. I don't know how accurate the PHPP data is and maybe this is a bit too theoretical, but it seems a good place to start. I can then tune this over time. Using the PHPP data I get that the cooling power required, based on exterior temperature is: required cooling power = (outdoorAvg24hrTemp-16.8C) * 270W Given 120m2 UFH and 10W/m2/K UFH cooling power, I then get: slab target temp = (outdoorAvg24hrTemp-16.8C) * 270W / 1200W With an average 24-hour external temperature of 25C, this would give a target slab temperature of 20.2C for example. Of course, for an internal target temperature of 21C (instead of 22C) the constant would need to change, or be enhanced to include an additional parameter. Any thoughts anyone? I remember @TerryE has some kind of similar algorithm working well for him, but not read much about how others do this.

I've had a chance to play with a few sorts as a DIY office jockey type. Copper is ace in tight spaces with lots of complex gubbins to connect up. Very compact. Very well behaved in terms of support; pressure drop; etc. Do yourself a favour and use press fit to allow 100% dry fit before assembly rather than end feeding as you go..unless you're really ace at measuring as you go. Undoing/redoing 28 mm tees or 35 mm tees in end feed is not fun. MLCP is perfect for lairy first fix labourers. It seals internally and the diffusion barrier is buried deep in the pipe. Feel free to drag it across concrete, around the corners of rough cut metal studs, step on it repeatedly, use it as a towrope etc. It'll seal perfectly every time. Compression nut or press fit. Not widely available in smaller diameters though and the fittings are restrictive. Hep2o is delicate as heck; what with sealing on that outside and being made of scratch prone chewing gum; but it's very much easier to pull through like a wire/available in smaller sizes and does better on pressure drop for a given draw off volume. If mistrusting somebody lairy to first fix - mlcp. If trusting people to first fix and caring for draw off volumes more - hep2o. And transitioning to copper/screwed brass for the fiddly bits in a plant room when required.

https://www.screwfix.com/p/mcalpine-boss-connector-white-22mm/719hr

Please! Midwich Cuckoos!

Solar powered lights behind their eyes..

Make them like the kids from that film, Village of the damned. Nobody will stop anywhere near your house then.

Should’ve clarified that without leaking would be preferable! 😂

Update on Guses tell tales. Week past Monday I went back to take the locking pins out the tell tales, now they are free to move and the adhesive has set. On two of them the locking pins were binding fractionally. Probably does not mean much as the fixings were probably settling in. I'll wait and see what things look like in another couple of weeks. Have asked the Client to keep an eye on them too and if they see movement to give me a call. That said I warned them not to look at them every day as they will start to live in your head.

You've been a fantastic help - thanks a million

I thought so too. I've read similar situations where people are just bitter and jealous so make it as difficult as possible?

ICE cars generally run a compressor mechanically from some rotating engine part, with a rotating "seal". Regular heatpumps have actual seals, or welds. Our old ICE car a/c never worked when we got it at around 5 yr old sadly. Tried to regas it once, didn't last long. 14 yr old Mondeo. One day we will ditch it and the leaf and get a long distance BEV with a/c, joy.

@Newlands Ian Well done on getting it through the check. I would be inclined to side with @JohnMo on this one and chuck in a dMEV or two anyway. I wouldn't bother with the undercuts for now. At the very least spend £5 on a cheap humidistat to keep an eye on the humidity. Its you who will benefit from the better indoor air quality and lack of noise anyway.

There is about a billion cars in the world, they account for about a quarter of global CO2 emissions. Now not all will have A/C, maybe 70%, and a fair number of them won't leak, and when it comes to scrapping them, some will be done properly. If we are to spend money on reducing CO2, car air con is not the place to do it. Probably a free air filter and set of sparking plugs will have a greater effect.

The regs are more guidelines than rules, as stated at their introductions. The bco has to be happy with the solution, so we can sometimes persuade them, if we can show the logic. If that logic coincides with the principles of the actual regulations then so much the better. If that can be on paper then it can go in the file to close the subject. I was once told ( non sarcastically) that if I knew so much about it, then present it formally, with calculations and references, so that he was persuaded, and so would be his boss if he happened to look.

Everyone would benefit from smaller class sizes, but apart from that, the education is the same. I am hardly a socialist, maybe a bit left of our current choices. Think Kenneth Clarke, rather than Tony Ben.

we have a series of 3 boxes for emergency access, all hidden. The first one gives a hint to the 2nd one etc. You need to know us to be able to understand the hints. The 3rd one with the key requires moving things to find, lots of things. We are remote and had a shed broken into about 10 years ago, that was done with bolt cutters on the padlock. Only took the fishing stuff though 🙂 Had done our neighbour earlier and took all his tools, guess they didn't want any more.

Not disagreeing about common sense. But leaving holes open in the building open isn't testing the rest of the fabric. You know if there is a 100mm hole and a fan is in it. You don't know there's a 100mm hole, cut by accident hiding out the way. The point is you test every building the same way, not make up the test to suit the outcome you want to see. I have two MVHR units and multiple inlets and outlets, they all get blocked during an air test, because that is ventilation over and above those leaks that occur during a build. You are not testing for known leak sources, you are testing for hidden leaks, to show the overall airtightness of the building. If everyone tests a different way, it's "shite in, shite out" and totally meaningless

I was at boarding school when I was 11. There were many things I hated about it. Don't think I was asked about them. (expletive deleted)ing child centric parenting. Just put some vegan food on the kitchen counter and a breast feeding friendly area sign up.

A ripper only works on very old nails where the slates have already started slipping. If the nails holding them are half decent galvanised ones all you'll end up doing with a ripper is breaking slates and bending the nails.

Worth a read, started as mlcp https://forum.buildhub.org.uk/topic/18834-unvented-cylinder-installation-spot-the-problem/

No you are right, removing slates/hanging tiles is a nightmare, a ripper is the tool of choice. My builder used hooks when my build was slated and they are far better IMO, you just need to make sure they don’t rattle in the wind by hanging them correctly.

I have two MVHR units, one with the inlet/outlet facing the prevailing wind the other not. Both use a combined inlet outlet unit. We are also on a hill so get some big wind. Never noticed an issue

Well, an email to BC is free so I'll try to argue my case as a first step. Not holding out much hope but watch this space...

Obvious question is why would you even want noisy on demand extract, when you can have silent dMEV. Greenwood Airvac CV2GIP can be had for £40 to 60 from eBay. Bathrooms and utility only need them as long as you have an extract cooker hood. Need to ensure you have circa 8 to 10mm undercut on the doors, but that should be there anyway, other wise your on demand extract is rubbish. But must say world is going mad, when someone wants to make there house leak more.

Good old Ebay purchase. Mine is a 6kW Maxa heat pump. Like @prodave says super easy to install two pipes, one to a 3 way diverter valve the other is the returns to ASHP. Height of winter no they will not achieve 400%, but overall they can and do. The advertised SCoP for my heat pump at 35 deg flow temp is 4.26. However CoP at 2 deg and 30 flow temp is 4.26. While at 7 deg a flow temp of around 26 will give a CoP of nearly 6. Add into the mix solar PV and that is offsetting running costs throughout summer and some summer months. I know solar thermal will make your DHW, but PV is making my hot water and providing cooling and offsetting my daily running costs for electric. In fact since the ASHP install, my electric bills during the summer are unchanged from last year (no ASHP last year - installed May 23). This year I am also running cooling (through UFH pipes) via the heat pump most sunny days for 6 to 8 hours, the equivalent of CoP for cooling, is around 6 while cooling, but PV is supplying the electric, so zero running cost. My immersion has taken my cylinder up to 80 the last couple of days, via the PV diverter, heat pump hasn't done any DHW heating. Even if you store water at 46 degs, they only recommend you heat to 60 weekly, this can easily be done by immersion, but its questionable if you really need to in the UK, unless you have immune system issues.

If you are considering solar thermal (a one trick pony) you obviously are happy with something on the roof. So fit solar PV. It will power anything that is using electricity in the house and if there is more generation than use, it is easy to dump the surplus to water heating. Most of us that do that have very low water heating costs in the summer, and lower electricity bills. An ASHP then makes better sense as it is yet another easy way to use some of that self generated solar PV. My ASHP was an ebay purchase for under £1K but you can get new for about £3K upwards. No harder to fit, in fact I would say easier to fit that an oil boiler, no storage tank, no servicing and no volatile cost fuel. While I agree oil may be cheaper now, it is a very volatile price, so may not always be so.

I haven’t read the answers But should you be getting your test results down The higher the score the worse it is 4-5 is really poor Most of the homes I work on are looking a two

An airtight test is meant to test uncontrolled leakage, hence why vents are taped for tests.

Copper and solder the lot. It is what I did. Looks neater too and is tried and tested, real-world long term.

MLCP any day, i used compression MLCP fittings, not had one single leak or weep, and no expensive tools needed

Feels all wrong - the better the air tightness the better the insulation works and the less the house costs to run, in energy and financial terms, so better for the planet. People might, still seems wrong, suggest a reversible scheme, IE do the core drill operation suggested above, keep the cores, have the air test and then replace the cores.

When viewing rental properties a few years back, we found a neighbour has plugged one of these from shed to shed at the bottle of the garden to pinch power. When I asked if there was a condition report done, the agent said "yes of course we've got the same guy checking all our properties".. "then I won't be renting any of your properties" I replied. 😂

Cheers for that @Gone West. Well, everyday is a school day, and happy to admit i was wrong. My foggy brain must not be in gear yet today. Still think that that is shite IMO. My cables always run either straight up, straight down, or left or right.

No I get it, it only has to wrap around the corner a little (20mm ?), if it’s code 4 lead (the thicker stuff it will just stay there without chasing ) it’s such a small area it will just stay there.

There is the outside chance that it's the end of a radial, he hasn't specified what type of breaker it's feed from. Socket radials are much more common thanks to the influx European labour

Mlcp (prefer uponor brand) . Press fit fittings.

This was inconsistency within the bco system. The local LA had been chatting me up to give them a go again. 'They had changed'. So we did, and they delegated site visits to the LA where the project was. 2i inspectors with different opinions, and double the list of queries. It was clear that one of them wasn't used to being challenged. We went back to private inspectors.

Plastic - layflat polybutylene myself. Some copper in places. I prefer to use polyplumb pushfit now over both Hep20 and Speedfit.

I'm using plastic push fit below floor, soldered copper up and down to the rads. Price and speed are a factor, but also potential for changes in the future. Not to mention long runs of copper always tick tick tick when heating up and cooling down

Something like Hep2O and copper where required. If DIY use Tectite push fit for the copper and Hep2O push fit, within Hep2O and interface between the two materials.

mmmmmmmmm. I have never used MLCP. I used only copper on my daughters with soldered joints (but i would like to have a go on one of those electric things.) In my other daughters, i used Hep, with no joints under the floors, ceiling, or walls. Plastic is so easy, so to answer your question, Perhaps MLCP with a bit of copper.

2.5mm2 is more than adequate, tell joiner you are worried about the thickness of the partition timbers and start him worrying!

Sounds like you need some edge beams around that part of the patio to separate the lawn from the path. It will also stop run off from the lawn getting onto the patio.

Is SEG not the replacement for FIT? Apply for SEG for the new array and see what happens? Or, if it was me, I would not registrar the new array and just export it and get the money on the FIT! There are no solar police! I am an advocate that all this stuff should be abolished, it should be as simple as installing a compliant solar generation system, the meters should be bi-directional - if you use a kW you pay for a kW, if you generate a kW you export a kW and the meter rolls back 1 click. Checks and balances could be added, such as max array size under this scheme, but it would just simplify it all and do away with frankly a lot of total rubbish.

But a radial is just rhat - it should feed a single oven via a single RCBO and an isolator. If you have 4 ovens, it is 4 radials. What it sounds like is that you want multiple ovens on the same circuit, and you need to be able to isolate each one (20A DP switch per oven) via an accessible switch. That would need a 4mm cable to the first point and then spur off for each oven with a switch, and for 4 ovens you need to consider diversity but you could even need a 6mm feed.

Why upgrade to 4mm for a single oven ..? A 2.5mm cable will handle 23-25A, and a number of the Bosch units come with a fixed lead that is only 1.5mm anyway. Up to 4.5kW then you are in the boundaries of a 20A RCBO, 20A isolator and 2.5mm cable