JohnMo

Notice the original poster of this thread was on the site specifically to post this and not been seen since. Was on the site about 5 mins in total.

Think you have answered your own question.

We have a similar buildup, but with a 150mm of steel reinforced concrete below the PIR. We did our floor with fibre reinforced concrete, 100mm thick with UFH pipe stapled to the PIR, finish was power floated, then either tiles bonded oak floor or carpet. Had to do some self leveling compound here and there. Aim for about 200mm of PIR insulation.

I would a - leak is immediately visible (by watching pressure gauge). If water, do it with water and anti freeze or just air. I filled mine with water and Screwfix antifreeze and left as it was, pressurised until I commissioned the UFH. I installed the manifold on some marine ply and made a foot so it was self supporting and cast it into the concrete. Run standard 16mm pipe. I'm on 300mm centres 200mm will be fine. Depth depends on how you want to operate. 100mm deep allows batch charging overnight on cheap rate, 40mm maybe not. Not sure I would bother paying for pre pressurised pipes. Pert-al-Pert pipe is nice to use as it has no memory unlike PEX.

No idea, but you would certainly be charged council tax, no getting around that, for long.

We are getting our council tax banding sorted out, I noticed that Scottish Water get involved as they are part of the charging on the council tax in Scotland. We got copied on an email where the council was confirming with Scottish Water if we were connected. If you don't do thing properly you will be tripped up one way or another.

As it's not saying % it's the unit prior to conversion to a percentage efficiency, so would read 97.4%. As the temperature get a wider difference apart the efficiency will likely drop. Not really being asked to do much looking at your figures.

Trouble with a leakage rate done at 50Pa, that's basically the same as gale on all 4 sides of the building at all times, which isn't real. From a SAP report a leakage rate of 7 at 50Pa, is an infiltration rate of 0.4217. So use that, plus any forced ventilation and MVHR efficiency of 0 if you don't have that.

Concrete screed is 100mm thick. Have an electric meter dedicated to the heat pump and all its associated controls etc. All the discussion below relates to house heating not DHW. Had a couple of days at a very steady 7 degs, so ran steady state for 26 hrs (but that included heating around 50T of concrete floor up from about 18 degs to 23 degs, a check on CoP that was about 4.2, when comparing calculated heat loss compared to electric consumption. So straight electric consumption for 26hrs running was 13.1kWh - Heat pump heating cycle was basically one on/off cycle per hour. Theoretical CoP should have a little over 5. The batch heating is a bit of a funny one, because on the face value the CoP is not as good as running for 24/7. But the run hours are way less, less than 7hr compared to 24hrs per day and during batch charging each run cycle was continuous, with no stop starts. But if it's cold the crankcase heater is on when you are standing idle, so is using electric. On the 15th at 5pm the heat pump stopped house heating. The meter read was 625.21kWh. Made some changes to force it to batch charge only including changing the WC curve. A reread of the meter just now and its on 638.2kWh, so 13kWh used over a period of 3 days and 4 hrs. ASHP run time was only 6.75 hrs of that, the crankcase heater on for remainder. If the heat pump was delivering it's full rated capacity for 6.75 hrs, that's 40.5 kWh, so CoP 3.1 including running the crankcase heater. But running for only 6.75 hrs, compared to running 24/7 over those 3 days if I ran normal WC, about 70 stop/start cycles instead of 2. Or comparing average consumption per hour, 24/7 running is 0.5kWh. Batch heating is equivalent of 0.17kWh per hour. Not sure how accurate that is, due to different temperatures and solar gain, but will monitor.

You really need to do the math. Look up the allowable pressure drops for your system, then look at the pressure drops across the different duct sections and any bends. Otherwise it's all guess work, rubbish in rubbish out.

Start with the basics are all or some of the radiators getting hot? Did you turn down the flow temperature on the heating last year? If you are not sure what you are looking at, get the plumber in.

Mine did, made2measure have them on their site for downloading. But the structural engineer stated what the wind and impact loading were. But calcs are for the whole systems they sell. I needed the purchase receipt and the supporting calcs for building control.

That makes sense.

Mix of hydro, gas and import, I give it few Watts free of charge

If you don't have a heat and unlikely to get on if you are happy A2A, why even think heat pump cylinder? Get one that fits the space. Sorry can't help you with the eddy. But we have a cool energy diverter, it powers 2 immersions, and has timers built in also.

Most of the UK fleet of nuclear is well past its original use by date, so not much of the forward thinking and planning ahead going on. Wind, and solar is quick to plan and implement, in Scotland at least. With a bit more thinking tidal and wave will get there also, tidal being a 24/7 generation option. Offshore wind most of the time option. We are, nuclear is just stupid expensive compared to other sustainable options. They have had since the 1950s and far, the option seems to drop bits in concrete and place in a cave, but mostly in warehouses or put it on a ship and keep sailing. And the plot of land the site was on after a couple decades decommissioning, construct a wire fence and pay for aimed guards to keep people away. Bit more thinking required. Today in my area (NE Scotland) the electric grid consists of 10% hydro and 90% wind. Scotland is mostly zero carbon already.

Tried up to 32 flow temp, but house was getting way to hot, and that was about 3-4 degs outside, think the summer house got to 14 deg after 24 hrs. Think the two layers of OSB and the laminate floor (and its underlay) are just to much for the low flow temps to break through. Would need a min flow temp of about 35 and above to make a dent in the heating. That's too hot for the house. The other issue is the house heating needs are so low and we are not needing the heating on for long. Did try to run the heat pump 24/7, running at the lowest flow temp (25), but the ASHP was below min output modulation, so ran for 20 mins and 40 mins off - so wasn't much use, could run the house like that, but didn't seem the most effective, as each start/stop cycle dents the efficiency. Found the happy temp for the heat pump is 28 or higher and it would run almost non stop over many hours, so have a WC curve set to 28 deg when it's 10 degs (OAT) and above, and at -8 to run at 36 degs and I am going back to batch charging the floor of the house overnight. Found this worked well at the end of the last heating season with the gas boiler. Have set the inside thermostat to force floor charging overnight if at midnight the house is below 19.4 Degs and at 7am the thermostat reverts to 18.5 deg to effectively force the heating cycle to stop. If the OAT well below zero and the house hasn't exceeded 18.5 deg, the heating would just stay on as long as required. - basically getting ready for E7 in a week or so. The other night the OAT dropped to 1 deg and the heat pump charged the floor, running continuously for 5.5 hrs, then not starting again for 24hrs and only ran for a 1-1/4 hours. Good thing so far is no defrosts have been needed, when it was 1 deg OAT, I went to have a look for frost on the evaporator and it was completely frost free.

A couple of thousand years to manage the waste for one. A few decades to build is another. Cost per kWh a third.

The thermostat

As a follow on from my previous topic on our summer room, which the wife uses as healing space. We installed UFH, which was to be run from the house heating system, but unfortunately the heat output of the system is pretty rubbish (due to the low flow temps for the house. Only getting the summer house to 15 degs. So purchased an electric radiator. Thought buy a decent one, so opted for a Dimplex. It has a built in timer and thermostat. One basic issue is the thermostat is built into the unit, so is measuring the temperature local to the radiator, not the room temperature. Room heat up time seemed very long, temp variable in the room. So solution was it install a wireless thermostat (has 16A switching capacity) - I had left over from the house build. A Salus WQ610RF, which comes with a self learning algorithm for electric heating and has predicted stop and start, so room learns when to start and stop heating. So thermostat on radiator is set to maximum, and timer is disabled. All programs are run from the thermostat. Screenshot of the heater activity (smart plug) prior to modification, lots of starts and stops of the heater, as a result heat up time was very long and room temperature varied quite a bit. After modifications, nice long heater run to get room up to temp quickly. Very short on off periods to keep room temp stable. Also note the power input seems to be modulated as same power setting is used on the heater.

What's that mean?

Computherm Q7RF, Amazon was the best price I found. Works pretty well for heating and cooling. If you are getting big overshoot turn the flow temp down a degree or so.

Yes, you then adjust the heat output by altering the flow rate, with the flowmeter, to balance the whole system. The way to trial it is to move the thermostats to say 24 and see what happens. Not sure the depth of screed you have, but batch charging the floor works well, we have 100mm, and can charge the floor up over 5 to 7 hours and we are finding that to be the cheapest way to heat the house. We take a hit in CoP on the heat pump, but the run hours are pretty low.

If you are only adding 100mm insulation upgrade to PIR.

Made2Measure.co.uk do them