Mini Split Install Questions.

buster · 04-18-12, 11:47 PM

I just installed a Gree Heat Pump 18,000 BTU. The outdoor unit was pre-charged for 25 feet of line set. The unit it rated for 208/230 volts which I have 246 volts. I happened to have a buck transformer, although not necessary, I wired in the buck transformer so since it's a minus 16 volt I have 230 volts. So I installed with 25 feet of total line set so I wouldn't have to adjust the charge. I pulled a vacuum to 20 microns and it settled after an hour at 196 microns. Yes, it took a day of running my vacuum pump to get it to that level. So I fired it up and it works really great. Here's my question - finally. I went out and grabbed the line set and they were HOT in heat pump mode. So I attached a Fluke thermal clamp to the 1/2" line (largest) and temperature ranged from 118 to 149 degrees F. On high, it finally settled down at 141 degrees. The current is supposed to max out at 12.49 amperes in heat mode. I measured 11.1 amperes maximum. The company that sold me the unit says I need to add freon due to the high temperature of the line set. I haven't taken pressure tests (only one fitting on the 1/2" line). I went inside to check inlet and outlet temperatures but the room was 86 degrees from my testing so I switched to cooling and the did some indoor measurements. Outside temp=51 degrees, inlet temperature inside=86, outlet temperature=61 for a 25 degree delta. Later inlet temperature=69 degrees, 40 degrees outlet for 29 degree delta. Does it sound like I need to do anything such as add some R410a? I didn't want to open the schrader valve to connect a pressure gauge if I don't have to. The Service Manual says it can only be charged by weight anyway so that's complicated. The seller says if it's low on freon, the compressor will burn up but I'm not seeing excessive current draws like I expected. Looking for any input and thanks so much.

04-18-12, 11:47 PM	#1
buster Lurking Renovator Join Date: Apr 2012 Location: Oregon Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	Mini Split Install Questions. I just installed a Gree Heat Pump 18,000 BTU. The outdoor unit was pre-charged for 25 feet of line set. The unit it rated for 208/230 volts which I have 246 volts. I happened to have a buck transformer, although not necessary, I wired in the buck transformer so since it's a minus 16 volt I have 230 volts. So I installed with 25 feet of total line set so I wouldn't have to adjust the charge. I pulled a vacuum to 20 microns and it settled after an hour at 196 microns. Yes, it took a day of running my vacuum pump to get it to that level. So I fired it up and it works really great. Here's my question - finally. I went out and grabbed the line set and they were HOT in heat pump mode. So I attached a Fluke thermal clamp to the 1/2" line (largest) and temperature ranged from 118 to 149 degrees F. On high, it finally settled down at 141 degrees. The current is supposed to max out at 12.49 amperes in heat mode. I measured 11.1 amperes maximum. The company that sold me the unit says I need to add freon due to the high temperature of the line set. I haven't taken pressure tests (only one fitting on the 1/2" line). I went inside to check inlet and outlet temperatures but the room was 86 degrees from my testing so I switched to cooling and the did some indoor measurements. Outside temp=51 degrees, inlet temperature inside=86, outlet temperature=61 for a 25 degree delta. Later inlet temperature=69 degrees, 40 degrees outlet for 29 degree delta. Does it sound like I need to do anything such as add some R410a? I didn't want to open the schrader valve to connect a pressure gauge if I don't have to. The Service Manual says it can only be charged by weight anyway so that's complicated. The seller says if it's low on freon, the compressor will burn up but I'm not seeing excessive current draws like I expected. Looking for any input and thanks so much.