Function And Control - Carrier 40VM Series Service Manual

Function and Control

ELECTRONIC EXPANSION VALVE OPERATION — Electronic expansion valves of the indoor unit regulate the refrigerant
flow to control superheat during cooling operation and subcooling during heating operation.
CAPACITY INDEX
7~18
24
30
36
Larger than 48
CAPACITY
Less than 12
15~18
24
30
Larger than 36
500P EEV Operation Driver
When the indoor unit receives the following signal:
• Signal to turn OFF
• Indoor unit error signal
• Indoor unit turns to fan mode
• Indoor unit turns to thermo-OFF
• Indoor unit shut down due to low temperature protection on the evaporator
The EEV's control uses the following logic:
• If the outdoor unit shuts down without cooling capacity requirement:
The EEVs keep previous opening for three minutes.
Then EEVs conduct 300P opening (EEV whose opening is not equal to zero will close to 0P first, then open to 300P).
• If the cooling capacity requirement of the outdoor unit is not equal to 0, the EEVs keep the previous opening for 25 seconds
after the indoor unit turns off, then close to -16P to reset the opening and standby.
When the indoor unit receives the turn ON signal, the EEVs control uses the following logic:
Table 6 —List of 500P EEV Opening in Cooling Mode
INITIAL OPENING
120
120
120
120
120
Table 7 —List of 2000P EEV Opening in Cooling Mode
INITIAL OPENING
300
200
300
400
400
MINIMUM OPENING
54
54
54
54
54
MINIMUM OPENING
104
104
104
104
104
7
MAXIMUM OPENING
480
480
480
480
480
MAXIMUM OPENING
2000
2000
2000
2000
2000