LG Heat Pump frustration
Comments
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Thank you for the support!
I split my time there, so I haven't been there since last weekend. I will be back tomorrow and report on the comfort level.
However, I suspect with the current tstat settings, I would be cold, as I was last weekend even with the setpoints substantially higher. Nothing has changed about comfortable the house is.
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I am in awe of the collective troubleshooting skills here!!
Unfortunately, I do not control the temp (or humidity) of the my residence (large apartment building).I can tell you that the room in which I am right now is 81F and 24%.
I think it is starting to sound like my problem is my problem.
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I can't believe @82°F you're comfortable.
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The OP may well be someone who prefers warmer thermostat settings.
That doesn't mean that his heat pumps are all working properly. I still think his first floor heat pump may not be working properly. It's running flat-out with no off-time except for defrost. That's only going to happen if it was perfectly sized for the heat loss, and @LRCCBJ has shown that is should have excess capacity even at 70 degrees delta T.
If the OP's thermometer reading at the supply duct was correct at 80 degree supply air, then the heat pump is not working correctly. We know the air handler supplies 1200 CFM. So the heat pump output in that case is
1200 x (80-72) x 1.08 = 10,368 BTU/hr, which would mean the heat pump is underperforming.
But if the contractor's claim on 100+ degree supply air is correct, then
1200 x (100-72) x 1.08 = 36,288 BTU/hr, which is right at the rated output.
Unfortunately the OP's thermometer reading at the supply grate may have been faulty, because in the photo, the thermometer is right on the edge of the supply grate where it will show a mixed reading from both supply and ambient air temps. A definitive test would be to place the thermometer directly on the middle of the supply grate and let it sit there for several minutes to reach equilibrium.
So it's an easy test. If the heat pump is running 100% of the time and putting out only 80 degree air at 1200 CFM, it's not working properly. But if it's running 100% of the time and putting out 100+ degree air, it's working properly.
Unfortunately the OP's thermometer photo doesn't give a definitive answer because of where the thermometer is located.
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@josephny, are you comfortable at 81degrees? Many people would find that to be uncomfortably hot. I have a friend who has Reynaud's syndrome. She always feels cold especially her hands.
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I need to get faster responding thermometers. Using a kitchen fridge magnet backed one.
I did not give it enough time after moving it into the room I’m in. It is a Thermopro brand and seems it is very very slow to adjust.It now reads 79F and 29%.
And I’m not feeling warm at all. Tiny bit chilly.
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Quite unintentionally, seems to me that one valuable lesson in this thread is that different people like or are comfortable in different space temperatures. This should be obvious, but… doesn't seem to be.
Maybe we'd all be better off if we had no thermometers with nice numbers on them — and just were able to set a thermostat (which also had not numbers) to where we felt comfortable and got on with it!
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
this thread took long enough to solve with numbers. Imagine how long it would take with just a blank dial 😅
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el
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All well and good but such an approach provides NO information as to whether the equipment is functioning properly. People do this all the time with boilers. As long as the house is warm, that box in the basement is completely ignored……………..for years!!! There is an ongoing thread on here today where the boiler has at least three different things wrong with it but it still runs………..barely.
I'm still baffled by the energy consumption of the first floor as compared to the heatloss. Something is amiss and it very well could be my estimated heatloss values.
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Wouldn't you expect a change in energy consumption as the unit went into defrost ASSUMing defrost is the period when the rom temp drops. I don't see one
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I would certainly expect to see a drop in output during the defrost cycle. I'm not confident of the data presented in the charts once it was confirmed that the temperature graphs were completely wrong.
Now we find that there is no accurate measurement of the vent temperatures as well.
Just forget it.
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"I still think his first floor heat pump may not be working properly. It's running flat-out with no off-time except for defrost."
It's a modulating heat pump. We know it's running, we don't know how hard. I would expect a properly sized unit to run continuously below about 40F.
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We do know the first floor heat pump is using about 3 kW continuously per his last bar chart. At an assumed COP of 2, that would be 20,400 BTU output, which is right in line with @LRCCBJ 's heat loss estimate of 20,000 BTU's for the first floor.
So that unit could be maintaining a 71 degree setpoint, while running at only half its 40,000 BTU rated capacity.
At 20,000 BTU output, the 1200 CFM air handler would be giving a temperature rise of about 15 degrees. 71 + 15 = 86 degrees supply air temp.
So it's possible that the first floor heat pump is operating normally, outputting 20,000 BTU/hr to match the first floor heat loss with the thermostat set to 71 degrees, with a supply air temperature of 86 degrees. Which is not going to feel warm to anyone.
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The problem is the fan speed is too high. OP needs to get rid of the logging thermostats and put back the original LG ones, and set them to automatic fan speed. Fan speed will be matched to heating load.
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DO we know where his data is coming from?
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Reducing the fan speed from 1200 CFM max to 749 CFM min would raise the DT by 50%, so that would be an improvement. Too bad the contractor didn't explain that to the OP.
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I wouldn't be at all surprised if the contractor came in, set the fan speed down, measured the temperature, then set the fan speed back and said, "yep, checks out!"
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Well, that was fun.
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Glad to hear it.
Informative, educational, and helpful, yes.
I don't know if the problem is the low humidity, or if there is something I am just not recognizing or able to articulate.
Thank you all so much! I learn so very much from you all.
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