1HP should be enough.

The surface area in contact between the 2 pipes are too small, the effect is negligible + the distance of travel between the 2 pipes also practically very short in between indoor & outdoor. Hence, it did not give much impact either.

There is another possibility. When the ambient is too hot, your AC capacity actually is reduced because the ability of the heat rejection is being reduced. The AC unit should perform well if the outdoor temperature within the factory temperature test range , if the ambient temperature exceeded the factory test range, indirectly the capacity of the unit will be reduced.

During the night time, the outdoor ambient is easily within/below the factory test range temperature , hence there is no issue arising from the possibility of capacity drop.

Your remote setting. You got check you set it with the "snowflake" icon or "water droplet" icon ? This one may effect also.

I guess the other may be correct, you need to get the unit to be serviced.

deleted - double post

This post has been edited by nihility: Feb 28 2022, 08:12 AM

Actually what is the reason you want to change from split to inverter / multi split?

For the non-inverter vs inverter, only the long usage time like light commercial / industrial will benefits from the inverter. For light usage for the residential, non-inverter vs inverter, the benefits may not be that obvious.

For the multi split, basically the system is actually few units of slit unit but they house the compressors in a compact space. Inside the single outdoor of multi split, there are 2 or 3 compressor. The piping to the indoor units will still be 1(indoor) to 1 outdoor(2). The piping length will still be limited to the capacity of the individual unit within the multi-split.

Prone to damage ? It should be same like the normal split unit. The only different, the cost for the new multi-split will be easily 30% higher than the total split unit of the same configuration / capacities because the factory have to change their production line for the multi-split production & the volume demand in the market is not high.

Normally the developer will provide the piping based on the worst case scenario, meaning the pipe can be used for both inverter & non-inverter. Yes, the AC installer will be able to check & confirm.