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JohnMo

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JohnMo last won the day on December 5

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  1. JohnMo
    So just do long cables, with no breaks between panels and inverter.
  2. JohnMo
    Yes, but you don't need to add anything for DHW. The way they test heat pumps is more for central Europe, which has a dryer atmosphere, so less defrosting goes on. So I would look at nearer 8-9kW (at -3) not a 6-7kW. But as mentioned turn down and modulation is important.
  3. JohnMo
    I got some stupid quote, a massive heat pump offered, even with an 'A' EPC. And an actual heat loss for house, close to 3.5kW even at -9 outside.
  4. JohnMo
    Just put the inverter in the loft, terminate direct to the inverter, then an AC isolation switch and then down to consumer units. Then you have PV array plugs and inverter plugs nothing else on DC side. Or just use longer DC cables and take then direct to the inverter location planned?
  5. JohnMo
    Really depends on heat loss - start with the basics do a heat loss calculation. Then you will know what size you need. 19 radiators in a heat seize of a house and 19 radiators in a low heat loss house require different heat inputs. This will give you an easy means of getting somewhere close https://heatgeek.com/articles/heat-loss-calculations
  6. JohnMo
    The reason I said in the first place was, that the flexibility comes from having a big energy store, then you can play tunes with how you heat your house. Pure weather compensation is fine with thin and thicker screeds, batch charge can only be done with thicker screeds. Batch charging can be useful with time of use tariffs. A few on here only heat on cheap rate periods. 40mm is more like a big radiator.
  7. JohnMo
    I would size heat pump based on a few criteria Over size ashp approx 1.2 to 1.4 for region of +5 to 0 to allow for defrosting. Make sure heat pump puts out a genuine minimum of 7kW at you design temp. Take note also of oversize to cover defrosting. Get a heat pump with good modulation. Size system volume based on 20L per kW output at minimum modulation of heat pump. Exclude in volume calculation any radiators with trvs and their pipe work. Exclude any UFH loops with actuators. Any volume needed, add by volumiser not buffer.
  8. JohnMo
    Pretty rubbish in a premium price point ASHP!
  9. JohnMo
    Put in 0 rather than empty. Put 0.3 to 0.5 in the ACH. This figure isn't airtightness its ventilation heat loss calculation. Airtightness does have an impact but its small if you are doing airtightness detailing.
  10. JohnMo
    Took my insulation at the wall edge out as far as the inside edge of the skirting. So bottom image but wider. I would do 200mm PIR and increase screed depth.
  11. JohnMo
    Via the same search, but direct wording from the Emneti website. The Tecno-Varia vent valves allow for automatic air evacuation, but with the patented Tecno-Varia version and the extra manual vent, it is also possible: - monitor the valve's regular operation; - accelerate air evacuation in specific conditions (e.g., system filling). Those were my words
  12. JohnMo
    You really should do an image search and let AI tell you Operation: For normal automatic operation, the top cap should be left slightly open. It also includes a manual vent function, which is useful for rapidly bleeding air when filling a new system. So is left slightly open to self bleed. Side to quickly manually bleed.
  13. JohnMo
    The trouble is, ASHP installer comes along and allows air into system. If air isn't fully purged after they finish the piping you get the situation described by @Nickfromwales. For me the ASHP installer should have revisited the purging.
  14. JohnMo
    Do you use a second pump (on the heater circuit), or does the system rely on buoyant flow across the heating element - similar to the original design for cylinder heating?
  15. JohnMo
    I used something similar on a 2kW heater it has a melt down after about about a month. You need a relay rated more like 20A, to put up with the switching loads. Build or buy something like this, this is what Grant Boilers use on heat pumps to switch immersions. Choose this link because it shows the inside of box. https://ebay.us/m/iXxCKs
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