Check system parameters
Split ODU – 6 720 817 722 (2015/06)
36
5
Check system parameters
6
Electronic expansion valve
Fig. 34 EEV driving circuit
Output pulse sequence
– In valve close state: 1 -->2 -->3 -->4 -->5 -->6 -->7 -->8 -->1
– In valve open state: 8 -->7 -->6 -->5 -->4 -->3 -->2 -->1 -->8
1. If EEV open angle does not change, all of output phase will be OFF.
2. If output phase is different or continuously in the ON state, motor will
not operate smoothly and start vibrating.
Temperature difference between inlet and outlet
depends on water flow rate and exchange-surface of the
heating system.
Symptom
Remark
No temperature difference between water inlet and outlet
Power consumption is low (<80% of rated current)
Refrigerant completely leaked
Check cycle
Temperature difference is ok (5-10K)
Power consumption is low (<80% of rated current)
Leakage of refrigerant or clog of cycle
Defective compressor
Temperature difference is ok (5-10K)
Power consumption is high (over rated current)
Too much refrigerant
Temperature difference is ok (5-10K)
Power consumption is in range of rated current (
10%)
Normal operation
Table 38 Temperature difference and power consumption
Suction pressure
Outlet temperature
Reason
Result
Higher than normal value
Higher than normal value
Defective compressor
Defective 4-way-valve
Current is low
Normal value
Too much refrigerant
High pressure does not quickly
increase when compressor starts
Lower than normal value
Higher than normal value
Insufficient amount of refrigerant
(leakage) or clogging
Current is low
Table 39 Pressure and temperature
6 720 817 722-37.1I
Output (Ø ) No.
Output state
1
2
3
4
5
6
7
8
Ø 1
ON
OFF
OFF
OFF
OFF
OFF
ON
ON
Ø 2
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
Ø 3
OFF
OFF
ON
ON
ON
OFF
OFF
OFF
Ø 4
OFF
OFF
OFF
OFF
ON
ON
ON
OFF
Table 40 Pulse signal output value and valve operation
