C would stop being as cold as when it was initially turned on after a certain amount of time. Why is that?
I have a split-type inverter A/C (LG HS-24IST). When initially powered-up, it cools down the room sufficiently and I can hear the compressor from the outdoor unit going at full speed. The compressor speed would gradually go down, presumably as the A/C is approaching the set room temp. But after a couple of hours or so, the room would feel not quite as cold. During then, if I listen at the compressor, it appears to be idling at a low speed. The problem is, even if I set the temperature to a lower setting (16°C, the coldest it could go), the compressor RPM will only marginally increase. The only way to make the compressor spin up to full speed is if I either turn off the A/C for a minute then turn it back on OR I temporarily set it to FAN (turning off just the compressor), then back to COOL mode. In either case, I can only get it to spin up to full speed to cool the room sufficiently if the compressor (and only the compressor) came from an off state. Before I call the repair guy and potentially get ripped off, what could be the likely issue with this A/C? Thanks!
Heating & Cooling - Inverter
Answers & Comments
Call the HVAC man, nobody on earth can answer this in a text box. the man does tests to find Truth, not guessing.
not only that but this is USA forum. we don't have your AC here at all.
it could be normal or is set that way for , low carbon emission reasons, why in the world ask here.
AC have many modes that run in, to AVOID PROBLEMS AND TO LOWER emissions.
if you read the manual on the AC and controller and are lost. why would you not call the AC man and get this resolved. (and learn to find one that is not a crook, sure)
the whole purpose of the variable speed compressor is to be lower carbon emissions. (greener)
that is what it does, if it messes up you get to pay the man.
Plus it has more things that can break, so that is what you bought.
"The compressor speed would gradually go down, presumably as the A/C is approaching the set room temp"
yes and no...
only if the room thermal load demand is less than the AC can do.
20000BTU, if you need more the compressor will go full tilt what else can it do?
you should read the manual and also see what options your has, a huge list I see.
That is a more helpful reply. Thank you. I will have to check for icing or if the temp sensor on the indoor unit is properly mounted.
Anyway, Jet mode essentially sets everything to max: Max compressor cooling at max fan speed for a certain duration (30 minutes, if I recall correctly) and switches back to a fixed 18 degrees after that. I had to use some home automation to set it back to comfort cooling (24 degrees). That command is sent via IR (Alexa). But I digress.
Anyway, back to the issue at hand... it was never like this when it was new. Let me give you a scenario:
Caveat: The percentage figures given are rough approximations only for the sole purpose of illustrating the issue I am experiencing.
When it was new:
I turn on the A/C, set to 24 degrees. The compressor spins up to 100%. The room cools down to near 24 degrees and the compressor speeds down to 50%, then idles down to 30% once the room temp of 24 degrees has been met. At this point, it will maintain the temp at 24 and will automatically speed up the compressor (and fan), on-demand, if the ambient room temp increases (ie. noon time). Now, if I turn on Jet mode, regardless of room temp, the compressor spins up to 100%, as do the fan speed and behaves like what I've described above. Needless to say, this is the normal behavior I expect.
Current behavior:
I turn on the A/C, set to 24 degrees. The compressor spins up to 100%. The room cools down to near 24 degrees and the compressor slows down to 50%, then progressively down to 30% once the room temp of 24 degrees has been met. That's normal so far, but this time, it doesn't seem to increase cooling as the ambient temperature gets hotter towards noon. If I enable Jet mode, the fan speed goes to max, but the compressor speed seems to be stuck at 30-50% duty only.
To make the compressor spin faster, I still have to "power-cycle" the outdoor unit, as I have described previously.
As before, I have disabled any weird modes, particularly energy saving. The A/C is setup to effectively work like a basic inverter A/C.