Carrier X-POWER Series Service Manual page 27

Carrier service manual
2.12~16HP have two DC inverter compressors.
Key Components:
Oil Separator: used to separate oil from high pressure & temperature gas refrigerant, which is pumped
out from compressor. The separation efficiency is up to 99%, it makes the oil return back to each
compressor very soon.
Low pressure receiver: It is used to store the liquid refrigerant and oil, it can protect the compressor
from liquid hammer.
Four-way valve control (ST1): Closed in cooling mode and open in heating mode
EXV control:
1) Max. Open degree is 480 pulses.
2) Generally, when system is plug in the EXV closes 700pulse first, then opens to 350 pulse and stand
by. When then the unit started, it opens to the right pulse.
3) When the running outdoor unit receives OFF signal, the EXV of slave unit will stop, while master unit
is running and slave unit stopped at the same time. If all outdoor units stopped, the EXV will close first,
and then open to the pulse of stand-by.
4) 8HP~12HP models have one EXV; 14~16HP models have double EXVs.
SV2: spray a little liquid refrigerant to cooling compressor. Open when any compressor discharge
temperature is higher than 100 .
SV4: oil returning valve. Opens after the DC inverter compressor has been run for 5 minutes and then
closes 15 minutes later. (For the system has only one outdoor unit).
Every 20 minutes, SV4 of each outdoor unit opens for 3 minutes. (For the system has more than one
outdoor unit)
SV5: for defrosting. In defrosting mode, the opening of SV5 can cut the refrigerant flowing circle, so the
defrosting process will takes less time. In cooling mode, it is always off.
SV6: for by-pass. Closed when the unit stands by and system is running at heating mode. Open when
the discharge temperature is over-high in cooling mode, and close when the unit is standby or system is
in heating mode.
High pressure sensor: to supervisor the discharge pressure of the compressor and to control the DC
fan speed.
For example:
Cooling mode launch sequence (The unit has accomplish commissioning):
Plug in and unit start----------SV4, SV5 open
Inverter compressor start at 40 Hz
compressor start (This step is omitted for 8HP&10HP models)
frequency will adjust according the capacity requirement.
3.2 Valve explanation
1
2
Note: For a single modular that is not necessary to connect with oil balancer

Connect the liquid pipe (accessory, field installation)

Oil balance pipe

Connect the gas pipe

Gauge point (cooling only type without)
Specification & Performance
60s later
U U
50s later
Inverter compressor start at 30hz
U U
3
4
60s later
SV5 closed
U U
40s later
Inverter compressor running
U U
R410a DC Inverter 60Hz
40s later
SV4 closed
U U
20s later
Fix scroll
U U
25