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[
VII
Control ]
-13- Subcool Coil Control (Linear Expansion Valve <LEV1>) <PUHY>
The amount of super heat is controlled and kept constant based on the bypass outlet temperature (TH8) of subcool coil
every 30 seconds.
The degree of opening is controlled based on the subcool coil outlet/inlet temperature (TH5, TH7), high pressure (Pd), and
discharge temperature. The LEV will be closed (0) during heating operation and when the compressor is stopped, and it
will be open during cooling operation with Thermo off.
The LEV stays open at 480 during defrost operation.
-14- Control at Initial Start-up <PUHY>
When the unit is started for the first time, it will run the following course of operation.
(1) Flow chart of initial operation mode
(2) Initial start-up control of P168-P234 models: time chart
Example
Start of initial operation mode
Step 1
P72~P144
P168~P234
Operation of No.1 compressor only
Exception : Completed if discharge superheat reaches above 25 C [77 F] within
5 minutes of start-up.
Step 3
Forced operation of only No.2 compressor only
Completed in the integrated operation time of 5 minutes
Completion of initial operation mode
f 60 Hz. Completed in the integrated operation time of 25 minutes.
60 Hz or less for the first 30 minutes , 85 Hz or less after 30 minutes.
No.2 compressor not in operation.
Completed in the integrated operation time of 40 minutes.
:
:
P168 - P234 types
P72 - P144 types
No.1 compressor
ON/OFF
No.2 compressor
ON/OFF
Completion of initial operation mode
40 minutes
Step 1
Step 3
5 minutes
Summary of Contents for PUHY-P168
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Page 38: ... 29 II Restrictions ...
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