JohnMo

Weight I believe, think they had issues before

But have floor output set at 50W/m² which huge, suspect you are nearer to 15 or below. We are 192m² living space, on 300mm spacing, our flow temp goes up to about 34 at -9,no way you would ever need over 30. Our heat loss with a very poor form factor is about 3.5kW, in fact just bought a 4kW heat pump. Do your own calculations, do not over size your heat pump. 7kW sounds huge.

Made from scratch by a local company, 4 miles from the house.

If you haven't try restarting the unit

Our glazed doors only came in double glazed, I upgraded to Krypton gas, quite happily sit next to them when it's super cold outside.

Bad idea for summer. But balance output, no issue, UFH in a low energy house is pretty good at self regulation, as floor temp isn't much warmer than room temp. So room heats up, floor stops output.

My stock answer is single zone, no mixers or additional pumps other that provided by heat source. Keeps it simple and costs low. All you need is pipes and manifold, no actuators or zone valves. If heat pump run everything from heat pump controller. Best design is to match floor output to room demand for each room. Then balancing is easy. No need for additional loops in halls, just space the loops transiting through halls out as if it was a loop. That hall is massive, would be stealing some space from it, for other rooms.

That's ok for cold, but you will waiting for ever for hot to arrive. I used a 15mm pipe from cylinder to a central manifold then 15mm to each wet room then split it to each outlet in the room. I would keep it simple just use Hep2O and add insulation if you have a secondary return system in place. Maybe some thin insulation if you feel you need it otherwise.

Not with a listed building on site. Ground mount them?

It will not need an additional jacket, keep your money in your pocket. The what steel is just a shell protector with insulation side. Mixer on the UFH, it's mixing the flow temp down to limit floor output and protect the floor. It will have a temp control knob,if you increase that the flow temp through the floor increases. The basic mixer just work on a ratio control, it's assuming 70 Deg hot water from a boiler, if you can turn it up do so. Adding even a couple degrees to flow temp will have a big effect on room temp (after 24 hrs) Other thing are you running the heating on all the time or an on off time cycle?

We are similar, but one room is 6m high and all glass bay window 6m tall also. We started zoned to death and it just didn't work for us, at the time the boiler just suffered from short cycling. We went fully open, single zone after a lot of iterations, and full weather compensation. Halved the gas usage at the same time. Now with ASHP we operate just the same. Now never feel this, full time heating also allows you to run the house way cooler, with no ill effects. In summer we just switch the heat pump to cooling to make the most of cold tiles and manage house temps. The mother of poor efficiency.

First complain to landlord or their agent, they are responsible to fix it and provide you heating that works. Start looking for a better rental property?

On a typical day we add 7 to 10kWh so we add 0.4kW heat pump sizing. This will vary by house size. But can fall back to immersion if we need to.

Not really correct, it's -3 in England and -5 for Scotland a minimum. But another figure you need to comply with designed to satisfy 99.7% of the year. So you ignore the odd day or two of very cold, but if but still needs to comply with -3/-5 and 99.7%. But you also design for a given user comfort. So various room temperature are specified in MCS and these are minimal design standards, a 90 year old or infirmed may want the room temps at 24 etc. There is no given numbers set in stone,it will vary by area. So be careful stating black and white numbers.

People generally do it to get to a plant room in the middle of the house. I would just run pipe along wall and cover in 25mm external insulation. Does that give any fire protection?

My cylinder and heat pump are long from each other and it was difficult wire, so I use the following - cheaper than a UPS A normal cylinder thermostat - like this - https://www.buildandplumb.co.uk//plumbing-heating-c36/heating-c264/heating-controls-c219/pipe-cylinder-thermostats-c358/eph-controls-eph-digital-cylinder-thermostat-with-high-limit-edbs-p11357/s29376 This operates via a time switch. So I have time and temperature sorted, this then powers a radio switch, which in turn powers a relay - but you could just use a wire to power a relay. The relay just moves to simulate the cylinder temp sensor, one setting is a resistor that simulates 20 degs, the other 50 degs. The heat pump controller is looking for 45 degs for DHW. So call for heat, relay moves to give a resistance equal to 20, once cylinder thermostat is happy relay is switched off, and heat pump thinks the cylinder is at 50 degs, so switches off all calls for DHW heating.

Going to add an automatic sanitizer to add chlorine (?) as needed, plus sand filter.

Manufacturers trying to be clever, without stepping back to understand what happens in reality. Ways around it?

Thanks all So looks like XPS300 should be ok,compressive strength wise. But I may need to to cover it with something to load spread to stop any point loads. So maybe slabs?

Think the bend radius for getting pipes through is way to small, firstly. Why run pipes through floor at all. Take them from outside direct in to house.

Need some help My next job is a hot tub, will be a round wooden one, heated by a heat pump. Looking to build an insulated base for it to sit on. Weight approx 2.4Te, diameter approx 1700mm. My initial thoughts were, dig down, DPM, PIR insulation 100-150mm thick covered in slabs (have loads to use up). But base will be square, hot tub round, heat will just move sideways out of the base and make the insulation useless. So not sure that works. Anyone any ideas?

Think you have the task of going the manual and the actual settings. There should be something that is flagged to do DHW as a priority after a power cut. It's not a normal ASHP behaviour. Normally resumes the last mode active.

In Scotland air tightness better than 3.0, balance inlet outlet ventilation mandatory, so MVHR. 3 to 5 MEV or dMEV (with trickle vents), after that whatever fancy passive vent intermittent fans etc, all with trickle vents.

There effectively a piece of string, but the string expands and contracts with changes in humidity - it senses room humidity it changes length as the humidity increases to open the vent more. You to have them coupled with MEV or dMEV fans in wet rooms. If these boost automatically, you get a system that self compensates for changes in room habitation etc. So example everyone in lounge in evening, vents in lounge window open, but rest of house vents go to min position, fans draw air through house taking most air from lounge. Everyone goes to bed, lounge vents close and bedroom vents start to open etc

Be careful using nameplate rating - you need a heat pump that does just under 6kW at -3 as you are England. Your defrost derate and DHW allowance takes it to just under 6kW. Most important bit is modulation at 7 to 10 degs, that where the heat pump operates most the time - long steady running at there temps makes the difference between SCoP of 4 or 5. They will come in thousands above grant, so why are you wasting your time. Your not going to get any change from the grant especially with SteibelEltron, as will cost as much as the grant just buying the unit.