Hi all!
Very mild heating today. Outside temp only 10°F below the 61°F setpoint in garage.
Thought id check the minimum modulation current on the mini split. Room temp was extremely close to set point but it was not off, it was throwing a healthy supply of luke warm air. Supply volts 119.2-120.8- 1 volt for line loss. 239v @ 1.75A. = 418w. Ive no idea if it can go lower but ive never seen it this low.
This is a 12000btu unit. They make 9000 btu units that would be capable of modulating lower than this one, guessing they could hit 200w or less. Very nice. Two of the 3 arrays were off most of today. Kinda sad but good problem to have i guess.
Friday evening i noticed programmable relay control rebooting by itself every 20 sec or so and relays of all kinds switching back and forth. I killed power and fixed it this morning. Turned out to be a 48-12 buck converter that was unable to put out 250ma while rating is 10A. I had a spare, swapped it in and running in a few minutes. The culprit i suppose is this P75NF75 FET, 75V 80A driven by a UC3845A PWM controller. Will order a few tomorrow. Its been running several years so i cant complain. Nice thing is the control switched to grid without anyone even knowing there was an issue. (My sweetheart is very easy to get along with as long as her cell phone and the electricity are working properly...whew