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Last seen: May 29, 2025
@robs Regarding the November operation as attached, the DT is increased to 8C to get 9kW at the flow of 16 l/min with both compressors. Mitsubishi o...
@robs Thank you. Interesting! I presume that the switch from 20 l/min to 15 l/min was made automatically by the heat pump, and not manually, to effec...
@robs Thank you for this. I attach a graph from the change you made. It is very interesting that you have reduced the flow to broaden the DT as this ...
@trebor12345 I will give you a quick simple explanation using the same diagram in non-defrost mode. Heat pumps work by extracting energy from the ai...
@trebor12345 @jamespa I do not know your timing sequences but I will try and venture an opinion here. I think that the unit is doing a two phase defr...
@agentgeorge I also have UFH with 4kW HP unit. I agree with your sentiments. UFH is the only way to go. Radiators just complicate things and it is w...
Theoretically there should be no penalty if there is no power surge on initiation. However, both Samsung and Daikin appear to have a designed-in perio...
@jamespa Talking about Mitsubishi, the @RobS post early on in this thread re 8kW R290 Mitsubishi is interesting as this unit is achieving constant 2k...
@old_scientist Apologies for the late reply. My 500,000 mile check-up was due with the quack. There are three DT’s to consider. Room-to-outside, emi...
I need to temper my previous statement. This Daikin is running a very high room temperature of 23C which means the flow temperature is too high for a ...
@jamespa These COP curves might explain something else that was puzzling me. Although the Daikin is running continuously at 1.6kW, its COP is not as g...
@jamespa @robs @trebor 12345 Attached is a more detailed power table. CAP and IPT are nominal integrated capacity and input power with defrost corre...
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Latest Posts
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RE: HeatGeek vs Octopus surveys: puzzling disparity - any ideas why?
Thanks for the update. Vaillant is a good choice, their...
By Batpred , 42 minutes ago
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RE: To re-pipe or not to re-pipe? Moving from oil boiler to air source heat pump.
@penval, really useful update. After all the discussion...
By Mars , 7 hours ago
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RE: Who's your electricity provider and what's your tariff?
@papahuhu I prefer to look at it simplistically. We d...
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RE: How Accurate Is My DIY Heat Loss Calculation?
D'oh - of course. I shouldn't post before my brain is f...
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RE: Questions about A2A for heating as well as cooling
@rob-of-york I would concur with the underfloor insulat...
By Toodles , 1 day ago
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RE: New Vaillant Arotherm controls link to existing thermostats ; wired vs wireless
Nothing attached! I have rads but UFH makes the case ...
By JamesPa , 2 days ago
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RE: Cooling with air to water heat pumps
Passive cooling should always be the first call. Keep ...
By JamesPa , 2 days ago
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RE: Do I add Air Con or MVHR to existing A2W ASHP?
@rob-of-york Thank you, I’m thinking along these same l...
By Toodles , 2 days ago
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@Mars Good questions! The downstairs unit did the maj...
By Rob of York , 2 days ago
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RE: Volumisers in Heat Pump Systems: Does Placement Matter?
@dave, I think @jamespa has probably identified the mos...
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RE: Plug and play solar. Thoughts?
My thought is simple. Bring it on and bring on plug in...
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RE: Heat Geek mini store vs pump size
Yes I agree, that’s why Heat Geek have most likely sele...
By Tomtheheatingengineer , 4 days ago
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@tomtheheatingengineer, thank you, and welcome to the f...
By Mars , 4 days ago
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RE: Is the "divide by 2900" rule still valid?
Really flow rate is a pipework limitation not a water p...
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