Hitachi RAC-25YH4, Service Manual, Page: 112 / 121

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HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT
MODEL RAC-25YH4, RAC-35YH4
1. Turn off the power switch.
2. Remove the electrical box cover.
3. Turn on the power switch
4. After waiting for 30 seconds, push the service switch for a second.
LD303 (red) will light and the unit will operate in the forced cooling mode at this time.
Never operate the unit for
more than 5 minites.
(Cautions)
(1) If interface signal (DC 35V) terminals C and D are not connected when the outdoor unit is in forced cool mode,
the outdoor unit defect indicator (LD301) will blink 9 times during operation to indicate communication error.
(2) If checking is done with the compressor connector disconnected, the unit will stop and LD301 will blink 4 times.
Be sure to push the service switch for a second again to stop the forced cool operation..
HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY
1. Connect the large dia. pipe side and small dia. pipe side service valve using a pipe.
Parts to be prepared
(1) Reducing union
2/8” (6.35 mm)
3/8” (9.52 mm)
(2) Copper pipe (2/8” and 3/8”)
Connect the small diameter service
value and the large diameter service
valve using the reducing union and
copper pipe as shown on the right.
Charge refrigerant of 300g
after vacuuming (*1)
The operation method is the same as “How to operate using the connector to servicing the outdoor unit”.
*1 The charging amount of 200g is equivalent to the load in normal operation.
Do not operate for more than 5
minutes
Electrical box cover
Unit top cover
Large dia. service valve
Reducing union
(2/8” and 3/8”)
Copper pipe
(2/8”)
Small diameter
service valve
Reversing
valve
Compressor
Outdoor unit
RAS_25_35_AW_109-118 2003.12.31, 11:00 AM 110