JohnMo

Everyone has different ideas, I just refuse to go under walls (for any reason), where a mad joiner can drill holes straight into a pipe by not being careful. Also hate small loops as this ends up driving a buffer, bigger manifold for a needless loop, manifold actuators etc.. Trial copy of loopcad will tell you if you are likely to overheat any areas, so any remedial actions can be completed before you install.

Are you reading from vertical or horizontal, from horizontal makes zero sense. 0 tilt i.e. horizontal/flat will give best part of nothing in winter.

I have a cool energy diverter, this can provide electric to two immersions sequentially, heat top first then bottom.

I really wouldn't install loops in these rooms, your manifold will be in this room and all the pipes having to go through the doorway. Big curve through that room with the pipes will provide more than enough heat. Then just do it all a single zone

With all piping systems you need to keep a watchful eye on head loss, with plastic being smaller than copper. Fitting have a quite big head loss and several in a line can have a dramatic effect once you start adding them up.

Me neither and I am over 60, soon as saw BTU I moved to the next thread. Leave BTU to USA.

A sanity check is your gas usage. Not sure of your DHW usage, but say it take 7kWh for that, each day. So you need your kWh usage for the heating season (your bills is a good place to find that) so, divide by number of days since you switched on the heating, to get an average per day, take away 7 for DHW. That will be the average kWh per day, double that figure will be somewhere near your worst day. Then divide that by 24 to give a kW heat input. Total kWh / days heating = average kWh per day Average - 7 = average heating day Average day x 2 = worst day Worst day / 24 = heat input kW On the worst day - most days not that

No it's based on the return temperature not the flow temperature

I just used white solid plastic pipe

I checked and ours wanted photos only, but had to show a tape measure to prove size. But check with your planning officer they are all different with different expectations.

The heating system and cylinder are run independently via a diverter valve so the cylinder doesn't care about the heating system. Only way to be sure is to do a head loss calculation. Our head loss to the cylinder was too big, so installed an additional pump in the return line at a fixed speed, pump starts at the same time as the diverter valve moves to cylinder heating and shuts off as the valve moves to UFH.

Why not cut out the middle man get the heat pump you want and a local plumber to install? Could be cheaper than the grant from the sounds of it.

Get accoustic ones https://www.titon.com/uk/products/window-door-hardware/window-vents-window-door-hardware/sf-xtra-sound-attenuator-vent/ But ideally also humidity activated ones. They are available https://brookvent.co.uk/acoustic-vents/ Also Duco and Aereco.

For me V2G is just a red herring, the suppliers will do just that - supply to grid. Tech been about for years. I would question if you actually need a 9kW heat pump hydrid. It would suggest your heat load is massive, the ASHP should run on its own down to about 7 degs and that is how you would size it, the boiler starts to kick from there and takes over the additional capacity required. It is more normal to see a 4 or 6kW heat pump a hybrid system. Battery for starting the ASHP. Battery size is really the important bit it's the inverter capacity - how many amps it will kick out on demand. I know my all in one starts a 6kW ASHP without issue. Size will determine how long you can draw from it before it goes flat. Question is do you need 100% capacity for all situations, answer is no. Last two days have been rubbish for solar and close to zero overnight battery ran out at 7 pm. No big deal. Really cold day, your hybrid will be mostly gas boiler run, so way less of an issue for battery capacity.

Mine started with a combi boiler, same as the original poster. If starting from scratch with an unvented cylinder you really should take the cold water from the UVC inlet group as a balance supply. If retrofitting as I did, I have a house inlet pressure control valve, as well as inlet control group on the UVC with the cold balance feed closed off. You also need a check valve on the UVC hot outlet to stop any reverse flow. Ideally you would feed cold to the cylinder inlet group, and balanced cold water from inlet control group to the cold water manifold. Hot water direct from cylinder to manifold.

We have the same, two of in the house, never ran out of water.

I don't disagree. But they all do apprenticeships, if joining those trades as a 16 or 17 year old, those apprenticeship would have taken 3 to 4 years. Why aren't they learning these basic skills or are they, and they choose not use them, as a rule of thumb is simple, even if its wrong or inappropriate. I did most of my plumbing because I could and what I didn't know, enjoyed the learning curve. Not because I didn't want to pay a fair wage. Electrics not interested in the subject, so paid the professionals for everything start to finish. They charged me their normal rate - used same company for the last 10 years, on 4 house renovations and a new build.

It says to me the plumbing and heating engineer apprenticeship is p**s poor and pretty much always has been or they have been trained with skills and choose just to use rules of thumbs etc because it's easy. Understanding heat loss and boiler, radiator and pipe sizing, condensing theory should all be bread and butter skill sets. Just because heat pumps came on the scene shouldn't really have changed anything - it's just another heat source.

Yes the only difference is the coil size, it's way bigger, so you excellent heat transfer. You could flow at low temps heat to 48-50, get very little heat loss at the same time. If you are future proofing make sure you size for a typical heat pump i.e. how many litres it holds, will be bigger than a normal gas boiler cylinder.

I did something similar to you, but slightly simpler. All plastic pipe (almost) Cold water entered house, tee one side to cold water manifold the other to the combi. Ran to combi in 22mm and then reduced down. Ran a single cold pipe into each wet room then branched inside the wet room in 15mm Hot water came from combi in 15mm to manifold and then one hot pipe to each wet room and then branched in the room as per cold. Each run from manifold in 15mm. Keeps number of pipe runs down, simpler, cheaper, same functionality. We are all UFH.

Bit of info on PDHW both articles are by Intergas, only because they came up first. https://theintergasshop.co.uk/content/189-why-hot-water-priority-pdhw-is-the-reason-s-and-y-plan-should-be-banned https://www.google.co.uk/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.intergasheating.co.uk/app/uploads/2022/07/IG_The-Knowledge_PDF_Final.pdf&ved=2ahUKEwii-OjQleeEAxUBgP0HHaqLC6AQFnoECCUQAQ&usg=AOvVaw0y-sovRdn1eVMgk6F1mGQ7

No problem at all, most likely a small boiler would do it. But do the heat loss calculation, if you don't know where to start post another question on a new thread, post as much information as you can, house plan, wall, roof and floor make up/insulation levels etc. Also any idea on airtightness etc. Also how do you ventilate?

Let's start from scratch First you need to understand your heat loss this will determine boiler size. Chucking the biggest boiler you can find is foil hardy will lead to rubbish performance due to likely short cycling. An unvented cylinder will give way better performance from DHW than a Combi. You can make them perform well, but most plumbers have zero idea. Boiler control Say a big fan NO to S or Y plan, you need priority hot water on demand and weather compensation for the heating. Ideally you will have an electronic mixer on the UFH so that is also controlled by the boiler. Cylinder use a heat pump cylinder with a 3m2 coil. Size the radiators for dT 25 The above will give a very efficient system and lowest gas usage.

That's a rubbish design. My Triton units uses Automatic Frost Protection During very cold weather, Automatic Frost Protection will detect temperatures that could form ice inside the unit. Automatic Frost Protection will reduce the supply ventilation rate to prevent ice build up within the heat cell. Automatic Frost Protection reduces the flow rate of cold air, thus allowing the warmer stale air to raise the temperature within the heat cell to such a level that prevents the formation of ice. As internal temperatures rise Automatic Frost Protection will increase the supply ventilation flow rate back to the commissioned settings.

The supplier said the underlay was, but wife wanted decent wool carpet, so not the best for performance. But not a fan of UFH in bedrooms really, now we have it. Our last house was built in 1830 and we never switched the heating on on the bedroom ever.