How to get broken heatpump fixed and running with replaced electronic.
Got Samsung ae080rxydgg 8kW air to water heatpump outdoor unit. There was holes in heat transfer pipes that had to be repaired first
Pipes have very thin wall and difficult to weld
After repairing, leak testing, vacuuming and filling R32 tried to get compressor starting with pump own controller. it turned out to be impossible without indoor unit. Next step was to try cheap Chinese variable frequency drive.
Bad luck! This VFD didn’t understand anything about BLDC motors. It was only able to speed up around 10Hz and then going to fail state because of over current.
Compressor type was BLDC Twin Rotary UB8TN8265FJWSG. There was not very much information available about it.
Next try with Optidrive VFD. Those have well documented BLDC option.
Following parameters were used:
P-07 kE = 160V
P-08 IN = 9 A
P-09 fN = 200Hz
P-14 = 201
P-51 motor type = 3 (BLDC)
P-52 Auto tune = 1
Optimal kE value was searched using minimum magnetising current pinciple presented in Tip & Tricks chapter.
Compressor was smoothly ticking to 200 Hz after parameter setup!
First test without automatic EEV valve control
This was quite bad result indeed but the compressor was working! Evaporation temperature was pretty soon exeeding outdoor temperature and energy was transfered to air instead of taking energy from it. Warming energy was coming from compressor used electricity.
Control Electronics
Temperature Sensors
There is 7 NTC temperature sensors in the unit.
8 pin connector:
1: Outdoor 10k NTC
2: Evaporator 10k NTC (moved to evaporator input)
3: Hot gas 100k NTC
4: Compressor 100k NTC
4 pin connector:
1: Water in 10k NTC
2: Water in 10k NTC
2 pin connector
Liquid line 10k NTC (moved to suction line)
Sensors are connected to bread board using voltage division principle using same label value resistor pair as NTC has. Voltage division outputs were connected to Arduino analog input pins 8..14 because some lower pins had interferencing resistance.
