Hitachi RAF-25NH5 Instructions De Service page 193

EFROST
Reversing valve defrost system is employed: it consists of balancing period
･
(1) efrost start condition
When all the following conditions are established, defrost is executed:
･
Normal operation
①
Heat exchange temperature is within defrost range specified by outdoor temperature and heat exchange temperature.
②
efrost inhibit period linked to outdoor temperature has passed.
③
(2) efrost release condition
If any one of the following conditions is established, defrost is released:
･
Heat exchange temperature returns (heat exchange temperature
①
efrost max time of 12 minutes has elapsed.
②
Released by condition
･ ①
condition (ASTUS=0).
Released by condition
･ ①
(3) Outputs during defrost
Indoor defrost request: Transmitted to all units being operated in heating mode.
･
Compressor : Balancing period for [T F414] seconds
･
[TSKTM2] seconds
period until defrost MAX speed [ EFMAX] is reached
Electric expansion valve
･
Unit being stopped : [FULL CLOSE] 30 seconds after balancing period has passed
Unit being operated : [ FCTPS] 30 seconds before balancing period is finished
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during balancing period: When remaining balancing period has elapsed, returned to initial
or during reversing cycle period: [T F415] Shifted to balancing period.
②
→
Accelerating by [ FSTEP]min
→
reversing cycle period [PCLOSH$] 15 seconds before balancing period is finished
→
of rotation speed of compressor, opened by [ FSPPS] pulses and reaches MAX opening
degree [ EFSMX] when rotation speed of compressor reaches [ EFMAX].
- 222 -
reversing cycle period
→
EFOFF).
≧
Starting of reversing cycle period by [S RCT2] min
/[T FSPT] seconds in remaining reversing cycle
-1
Balancing period for [T F415] seconds
→
→
balancing period.
→
for
-1
[FULL CLOSE] during
→
Synchronized with step-up