JohnMo

legionella, not really sure that's needed in the UK as all supplied water is disinfected with chlorine. OSO make some good cylinders with very low heat losses. SAP calcs should give total house instead of room by room. In the boffins corner on this site is a heat loss calculator. Simplistically in weather compensation mode the boiler runs 24/7, it manages the system flows by looking at flow and return temps. Once the delta between the two temps reduces, it shuts down the boiler, but continues circulation of CH water. Once the temperature difference increases it fired the boiler. My manual says Explanation when used as a 100% weather dependent controller The WiZe thermostat can be set to work as a 100% weather dependent controller. This means that the room in which the thermostat is located is no longer imperative for temperature control. Together with the information from the outside temperature, a central heating (CH) flow temperature is worked out which is sufficient to heat the house. Thermostat valves on the radiators allow an individual temperature setting for each room. Required installation parts: a. Outdoor sensor (boiler-specific) connected to a boiler (refer to boiler’s installation instructions). Mounting on north – north/east facade of the house. Prevent outside influences such as snow, ventilation air or chimney heat. b. Thermostatic radiator valves on the radiators in the house to individually control the rooms. c. If ALL radiators are fitted with thermostatic radiator valves, the installation MUST be fitted with an automatic bypass valve. Refer to to boiler installation manual. I take the thermostatic valves are there more as a limit stop on temp, so if you want the room at 21, you have balanced the system to give you 21, you set the thermostat at 22, so if the sun's shining in the window the heating is switched off in that room.

We have our manifold in the utility and all room pipes lead through hall. So instead of bunching them all together we spread them out, heating is from the flow and return pipes to other areas. Lounge has two loops, kitchen diner another, kitchen diner loop also travels through bathroom. All operated from single stat in hall. We also have loops in bedrooms and one ensuite. Ensuite loop is always on when pump running, bedrooms flow turned down so background heat only.

Advantages Smaller buffer or no buffer, less likely to short cycle the heat source. If well insulated, all the area will be at very similar temperature anyway. How do you have 5 zones with 4 stats? Do you mean 5 loops and 4 stats?

Think there may be a broken record that keeps saying "if it wasn't for Brexit..."

Really would not bother, UFH is a low temperature heating system and really needs to be on for lengthy periods and not really suitable for bedrooms where you want the room warm a short period before and after sleep, but not warm when in bed.

I really would specify everything suitable for a heat pump, it will all give advantages to a gas boiler. UVC, with a heat pump coil, will accept lower flow temps, which will in turn keep you inside condensing mode of the boiler. You can heat to circa 50 instead of 60 plus. The heat exchanger coil is huge compared a gas boiler, which will have a better approach temperature and quicker reheat time. Radiators, use double panel rads to get twice the area, or half the size. I would and do have electric only towel rails, use them any time of the year without have to fire up the heating. Just 400W elements in them, have UFH in the bathroom and en-suites. Operate in weather compensation flow temps are low, boiler are super efficient, running costs low whole house an even temperature, although with suitable balancing you can get cooler rooms if you want. Read heat geek website for some good info.

Make sure your ground floor is well insulated, 150 to 200mm PIR. After that you need a 6/7/8 port manifold, pump and mixer, the UFH pipe, wiring centre and a set of actuators. Pricing as above I did mine £1100 most my bits came from Outsourced Energy. Treat the whole ground floor as a single zone, operated from a single thermostat, something like a wired Salus SQ610. Try to go clever with phone app control and loads of zones, you will rack up costs and they are pointless as the time to switch on and have a warm house can be 6 or so hours. Keep it simple the boiler or heat pump will be happy and so will your pocket now and in the future. If you try to split the UFH heating you will need a buffer. Do the floor at 150 to 200mm pipe centres. Download LoopCad and have a play and design yourself.

Best bit if advise ever

But you get free postage (except Highlands and Islands), if your daft enough to pay 10x the normal price.

Atag manual has all the numbers, snapshot attached

I used https://www.itstechnologies.shop

I didn't go decentralised in the end, but did install two units instead of one. A small and a large unit. The small one does the two bedrooms and two en-suites. I only have to boost the small one when we use the shower.

First reason for a cylinder was to enable PV diverter and offset DHW and possibly heating/ adding to CH. Future plan is to also add solar thermal. Thermal panel currently sat in garage waiting to be installed. The buffer when in CH mode only gets heated to about 30 to 35, so heat loss is negligible, but it hot enough to pre heat water going to combi for DHW. Reason for combi was hot water on demand, without having to store hot water and the associated heat loss. To get everything to work sounds easy, but has taken a couple of revisions to get to it function efficiently.

This arrival tells you all about the heater etc. https://buildequinox.com/news/?id=4711

As I said loads of entries ago, the heater is stop liquid refrigerant forming in the lube oil. If you could or did disable the heater, you would be buying a new compressor quite quickly. The only way to stop this load is to switch the unit off at the mains. When the unit restarts it will go through a heat up period to ensure the refrigerant is expelled from the lube oil before starting the compressor. If you are using 5kWh a day on standby, while waiting to heat DHW, you may as just switch it off and use your immersion.

Min flow rates may be important for some combi boilers, but for anything else, min flow rates don't make much difference.

Deal directly. I did my own design, as there system didn't give the 0.5 ACH required without adding a third unit, for a new build in Scotland, so became cost prohibitive.

The other similar option is Fresh-R. When I was looking, they looked better flows and price. This is the scheme they quoted for me. House is 190m2.

Approved install only for the grant. Assume they would organise the EPC

There are only single or three phase, as far as I am aware, so you are really asking for two single phase meters. Double the standing charge of a single meter. No wonder they are confused. You seem to indicate you have there 100 amp fuses, only one is being used. So did your house at some point have 3 phase, hence the three fuses?

As mentioned if going weather compensation, don't waste money on flashy thermostats, the radiator just need TRVs, UFH as single zone. Set up weather compensation so UFH runs all the time without overheating the house, flow temps will be closer to 25 than 45 degrees. Radiators are you too late to increase size to future proof, set up with a max flow temp suitable for a heat pump. Boiler sizing can be difficult with a combi, as you want a big one for DHW, but they tend to be huge in a well insulated house for heating. So may benefit from a buffer to ensure long boiler run times. We have a big combi (Atag A35ECX) with only a max heating demand of around 3kW. Have a 160L buffer with a DHW coil in it for pre heating cold water to combi DHW. The buffer is also heated by solar, so big reduction in gas consumption in the summer. The water leaving the preheat coil, if it is above 45 goes straight to the taps, below 45 goes through the boiler heated to 55 degs. We can run three showers from a combi. If you are thinking combi, the only real way to get consistent performance all year round and the ability to run multiple outlets properly is with pre heat on the cold water. Not sure where low loss headers come in on a domestic install, just use close coupled tees, £2.50 instead of £250. Or if you have a buffer that gives you hydraulic desperation. I would have a pump and thermostatic mixer on each manifold for UFH, as it easily allows you to run different flow temperatures and it also automatically give hydraulic separation from boiler pump and also acts as limit stop on flow temperature to protect the floor.

Most likely the heat will be similar to an airing cupboard. You could insulate and box in the manifold and any of the pipes. We have Louvre doors on our airing cupboard, where the UFH manifold lives. If you want Louvre doors custom made, we used these for the ones we have. Good service, doors didn't even need painting. Simply Shutters Limited. Tel: 01842 814260 Fax: 01842 814460 http://www.simplyshutters.co.uk

This is all it needs, https://www.screwfix.com/p/bottle-air-vent-15mm/34359?tc=TA5&ds_kid=92700055281954514&ds_rl=1249404&gclid=Cj0KCQjwwJuVBhCAARIsAOPwGASEU9pcMfS0jV7msoGiH8MQI8Z0lWWqvgrLvrNS4x4WH42gipahiZsaAiwEEALw_wcB&gclsrc=aw.ds No idea where they get the need for external venting. I would check to see what else they are putting through the external wall.

For accoustic and other insulation you want no gaps. The additional for accoustic is you don't want the insulation bridging the upper, lower surfaces. Not really seeing any issues.

We used flexible external tile adhesive from B&Q for attaching stone slips. https://www.diy.com/departments/mapei-super-flexible-grey-tile-adhesive-20kg/38144_BQ.prd?ds_rl=1272379&ds_rl=1272409&ds_rl=1272379&gclid=CjwKCAjwnZaVBhA6EiwAVVyv9IssxJV-9uIJ6KgTYlWqGQqC49F8jyGu0_3At2PzDwuMc59QgehDIhoCg3YQAvD_BwE&gclsrc=aw.ds&storeId=1217