Hitachi RAM-68NP3B, Service Manual, Page: 37 / 79

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MODEL RAM-
68
NP
3
B
EXPANSION VALVES
*
Compressor rotation speed
Indicate number of operating indoor unit
The compressor speed and duration during steady speed period is as below:
When the compressor is started, it will be in steady speed period.
TSKSPT (sec) until the target speed is reached.
After the steady speed period is finished, the speed increases at the rate of SDSTEP (min-1) within
SDRCT1_C2
SDRCT1_C1
when the outdoor temperature at start 40°C or more, and to PSTARTC*_d when it is less than 40°C.
steady speed period is fi nished, the TD control is entered. The start openings are set to PSTARTC*K_d
The start openings are held during the steady speed period when the compressor is started. After the
The expansion valves are initialized when power is supplied. The valve for unit 1 is fully closed (–520
pulses), and then that for unit 2 is fully opened (480 pulses). The valve for unit 2 is fully closed (–520
pulses), and then that for unit 3 is fully opened (480 pulses). The valve for unit 3 is fully closed (–520
pulses). When the valve for unit 1, 2, 3, is fully closed (0 pulse), start-up is possible.
Outdoor
Temperature (°C)
Duration
(sec)
COMP Speed
(min¯¹)
≤ STAROTP_C
> STAROTP_C
TSKTM1_C2
TSKTM1_C1