Protection Control - Sanyo SPW-C483GYH8 Service Manual

1. Compressor Control
(6) For outdoor units, when one compressor is running, the other compressor starts after the high-pressure valve is
held off, the low-pressure valve held on, and the save valve held on, all for 30 seconds. (22.4 kw, 28 kw outdoor
units)
(7) The control in (3) ~ (6) above takes precedence over all other control.
(8) After cumulative number of minutes (180 min. – number of indoor units connected) of continuous compressor
operation, the unit stops operation for 3 minutes to detect outdoor temperature by thermo sensor located at heat
exchanger.
(9) Current capacity speed increase
The microcomputer selects the optimum value for the speed at which the current capacity increases according to
the operating conditions. In the fastest case, the current capacity immediately increases to the maximum; in the
slowest case, the current capacity increases at 1 step / 90 seconds.

1-2. Protection control

(1) Main principles
If the current capacity decreases, it does not increase again for 3 minutes.
(2) Evaporation temperature control
1
Of the E1 and E2 indoor coil temperature of all the thermo-on indoor unit operating in cooling mode. The
lowest is taken as the minimum evaporation temperature (=Te) and the control indicated below is performed
every 30 seconds.
Minimum evaporation
temperature (Te)
↑
7.0 ˚C
6.5 ˚C

3.0 ˚C
2.5 ˚C
↓
2
When TEST RUN selected for even one of the indoor units operating in cooling mode, the current capacity is
always allowed to increase.
3
For 3 minutes after the compressor start, the current capacity decrease is the current capacity increase
inhibited.
4
At the minimum current capacity, if evaporation temperature control requires further current capacity decrease,
it is treated as current capacity increase inhibited for 10 minutes and the unit does not stop operation.
(3) Condensing temperature control
1
Of the E1 and E2 indoor coil temperatures of all the connected indoor units, the highest is taken as the
maximum condensing temperature (=Tc) and the control in the table below is performed. This control is
performed every 30 seconds.
Minimum condensing
temperature (Tc)
↑
63.5 ˚C
63.0 ˚C

57.5 ˚C
57.0 ˚C

50.0 ˚C
49.0 ˚C
↓
2
At the minimum current capacity, if condensing temperature control requires further current capacity decrease,
it is treated as current capacity increase inhibited for 10 minutes and the unit does not stop operation. When
this 10 minutes is up, if the condensation control is still on current capacity decrease, the unit stops operation.
However, if the maximum condensing temperature is 63.5 ˚C or higher, the unit stops operation immediately.
The 10-minute timer is cleared if the control is moved into any area other than current capacity decrease or if
all the compressors are stopped.
Control
Current capacity increase allowed
Current capacity increase inhibited
Current capacity decreases 1 step
Control
Thermo-off
Current capacity decreases 1 step
Current capacity increase inhibited
Current capacity increase allowed
II - 3
Processes and Functions
SM830052
2