ProDave

I would be surprised if it was screw penetrations. To allow yourself some investigation time can you rig up your own blower door? I used some OSB, some cardboard, an old desk fan and lots of duct tape. This won't get you a reading but will allow you to spend as long as you like going round with something that makes smoke, e.g. Joss sticks, to investigate where the leaks are.

Is the "poor" score really an issue? Are you hoping for passive house certification. I too got a poor score of 1.4 without being able to pinpoint where the leak(s) were. But the end result is still a very low energy house and an as build SAP score of A94 so not entirely shabby.

I spray with diluted bleach from a spray bottle. Best done when you are expecting rain shortly afterwards to wash it off.

I would leave as it is. the cost saving is not worth it. Mine is controlled by 2 room thermostats and a timeclock, to make it controlable in the same way as a boiler so most people would understand it. the timeclock has a holiday mode, but that just turns it off for a set number of days.

And a pub. My SWMBO worked at Headington Hill Hall for a while. (Maxwell's Council gaff)

Where abouts? That's where I grew up as a boy.

The other thing i did today as well as preparing a better base in the pump chamber, was I contrived a long hose from my immovable air compressor in the garage, to the treatment plant, just to blow some air down the pipe to ensure it was not blocked, and it ran free and you could hear the bubbles blowing in the "contents"

Well I have made a decision and ordered the £45 piston pump. It's advantage should be longer life than a diaphragm pump. but I expect it will be noisier. In preparation for that I am going to cut a board to sit in the pump chamber to sit on some foam. The default pump chamber in the conder TP is just like a plastic bucket with the pump sitting on what is doing a good job as a drum skin. You could not design a housing to me more noisy if you tried. The same make of pump as the one I have bought also do these diaphragm pumps that look remarkably similar to the Charles Austen type. But for those the spares are available individually including the air chambers and the flap valves contained in them, so if I did go back to another diaphragm pump, that would be a good argument for choosing one of those. It really annoys me that the spares are not available other than in a kit, for the ET100

No special treatment. Solum was built up with compacted infill after strip founds and under building done, then DPM then thin concrete screed poured. Under floor space ventilated with air bricks so assumed to be a dry space. Normal practice for a timber frame with suspended floors.

Sorry I did not describe it well. JJI 300mm deep engineered timber I beams for the floor, as light as a feather to carry. Here they are being insulated before being covered.

Thanks for the recommendations for the Secoh. The cheapest I have found for that is £160. That's still a hard sell when I can get the Chinese piston pump for £45. It would have to last 3 times as long before needing a service.

Timber frame build, strip foundations, I beam joist floors, insulated and covered in OSB. Lay battens (following joists) Lay UFH pipes. Fill gap with dry pug mix sand / cement as a heat spreader. Lay Engineered Oak floor as structural floor spanning battens.

No thought from anyone? My choices seem to be spend £40 to replace the diaphragms in the ET100. Yes that will get it working again. BUT you have to buy a kit that also contains a new armature (2 magnets moulded into a plastic armature) I am not convinced that needs replacing and I have not found anywhere to buy just the diaphragms. And as for being forced to buy unnecessary parts, there is also 2 sets of flap valves in this pump that do not get replaced with this service kit. The larger Charles Austen pumps do replace the flap valves as part of the service kit. So one has to question how many times can you service this pump with this kit before the flap valves give up? OR I can spend £44.99 to buy a completely different but new pump. It will all be new. It may be better and last longer, it may not. But if the "service" cost when it needs it is only £5 more to get a completely new pump next time, it has to be worth a try? Is there nobody reading this that has tried alternative pumps and can post their findings, in particular how long they last and can they be serviced or do they need replacing compete?

I sprayed my coffee all over my laptop when I read that. Made my day. Great sense of humour.

Out in the garden today, I noticed there was no noise from the treatment plant, the Charles Austen ET100 has failed again. I have once replaced the diaphragms in this pump, I don't recall exactly when and I can't find my previous post about it, but it does now seem very long ago that I replaced them. (if anyone can find my previous post please post a link to it) So the question is, do I replace them again? And accept this is a design of pump with an inbuilt short design life of the diaphragms? Or are there alternatives available that are better, more reliable and possibly lower power? I know these are generally talked of as good pumps, but to me something that needs servicing so frequently does not seem a good design. How about this: https://www.ebay.co.uk/itm/315879624105?_skw=100l%2Fm+piston+air+pump&itmmeta=01JJ2C6CWW195RC06F730H2JT0&hash=item498be48da9:g:dOUAAOSwa2VnEMrs&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKm21zAzCS4zNd2jnxfrrOBkOhQYhAk7CosWXuQypC5wJb6PfvsNVkMOBejzWhXwVDjHUnawcrurG%2FiIsbWdtpK%2Fn8IwRJZJP8M7oQQgPTxjf%2BRiq7GH1iDIoBnPZGgGTwO4j0vTT7Wimo9wYGyM0IRgNX79VT%2B0F5RTNeR24E6dCJ86hGQoWhtrDsRU4%2BExDuMp6nvrHeqB6iyjGykP7uwnOH4F0eSd%2BtG3ikLuqrSuKWOLLWQVKQ1ID679iWiY4E4eWE5W00urRUrvWQ%2FZacju8p3mCAHzPjJTq1hBl4CtUw%3D%3D|tkp%3ABFBMzs6ZzJBl An 82L/min piston air pump that consumes 60W of power for £46.99 To put that into perspective the ET100 diaphragm pump is 100L/min and the service kit alone costs £40 each time it goes wrong and it consumes 105W of power.

The overall flow temperature you are seeing is the result of the return temperature, the flow rate, and the power you are putting into it with the heater. I would wager if you valved off the "off" heater, you would see exactly the same figures as you are still putting in the same amount of heat.

Download the heat loss spreadsheet from this post, it proved very accurate for my build. I would be looking to improve floor insulation in your build. We have suspended wooden floors with UFH but wood or slate flooring throughout and that achieved a U value of I think it was 0.13 and works well with the UFH. Carpets will slow down heat delivery

1) What U values are you expecting to achieve for the walls, roof etc? your house is about 92 square metres. Ours is 150 square metres and has a heat demand of about 2.3Kw at -10 outside. What dis you use to calculate your heat loss? Why not UFH? Easy to design and build at construction stage, leaves all your walls free of clutter and runs at a lower temperature than radiators so more efficient for the ASHP. Typically out HP will spend an hour per day heating DHW, so your HP would need to provide the required heat in 23 hours to allow that. Heat pumps generally do heating or hot water, never both together, and most allow different flow temperatures from the HP for each. 2) heat loss through the roof is exactly the same calculation as the walls, you just have to work out the surface area of the sloping roof, which will be more than if you had put a flat roof on the building. 3) depends where you are. I calculated worst case heat loss for -10 outside and +20 inside. The cold spell a couple of weeks ago we got to -12 here and some parts to -16. You don't want average coldest unless you are prepared to be cold, or use another heat source (e.g. wood stove) when it gets really cold, which is why I designed for -10. the average is much higher than but a winter anticyclone and the cold can hang around a long time.

My point was I believe (correct me if I am wrong) you can only get the BUS grant is cooling is not enabled? When you dig into the exemptions and conditions, you could be forgiven for thinking the government want to make it appear they are promoting heat pumps, but then put in conditions that restrict the number of installs, and then at some future point they will say something like we had the policies but people did not take it up, so not our fault there are not enough.

Let them get built in. If they even notice and complain, apply retrospectively, and if refused fit some ON roof ones over the top to demonstrate what nonsense it is. During my planning, I only realised at the last minute that I needed PP for the ASHP so quickly added that at the last minute. All these sort of green updates should not be needing PP imho.

I find it absurd that they exclude heat pumps that "can be used for cooling" for being eligible for any grant. The objective is to get people to reduce fossil fuel usage. Someone with a gas boiler has the incentive "it might be very slightly cheaper to run if the install is perfect" but even with the grant it will cost you a big wad of £££. That is it. No wonder they are not queuing up. If they were offered a system that not only would cut your fossil fuel use, might be a bit cheaper to run, AND could cool your house in a heatwave, they might be a little more interested?

Is that a warm roof, or do you have insulation to go in first?

Yes picture of what you are trying to board onto. It does not matter if the last support of the PB is not right at the edge, it is not that bendy. One of our gable ends (closest we have to a hip) before the counter battens went on And after plasterboarding

Hot having seen all the floor plans, if you went got 5 bedrooms all en-suite, would there be any shower or toilet that was NOT accessed through a bedroom?

Just to avoid thread drift, if we want to discuss failed government projects, perhaps someone could start a separate thread for that.