Carrier MMY-MAP0724FT9UL Service Manual page 68

<Other points to note>
1
Cooling operation under low outside temperature conditions
1) If pressure falls to extremely low levels, indoor units may be shut down via freeze prevention control
based on the indoor TC sensor.
2) If pressure falls to extremely low levels, frequency may be reduced via cooling capacity control.
3) When the discharge temperature sensor reading falls below 140°F (60°C), the frequency may be
increased above the level called for by the commandreceived from the indoor unit.
2
PMV (Pulse Motor Valve)
1) When the power is turned on, PMVs generate a tapping sound as they are initialized. If this sound is not
heard, there is a possibility of faulty PMV operation. However, in a noisy environment, it may simply be
drowned out by ambient noise.
2) Do not separate the actuator (head section) from any PMV during operation. It may result in an
inaccurate opening.
3) When transporting (relocating) the set, do not, under any circumstances, keep the actuator separated. It
may damage the valve by causing it to close and exposing it to pressure from sealed liquid.
4) When reattaching the actuator after its removal, push it in firmly until a click sound is heard. Then, turn
the power off and back on again.
<Schematic diagram for oil equation control>
Unit
transferring oil
Header unit (MMY-MAP0964FT
PMV1 PMV2
PMV4
TE1
TE2
SV11
SV
SV
SV5
SV
TL
SV6
FP
SV3D
separator
SV
Liquid
SV41
tank
SV
TD1
Comp.
1
SV1
SV3E
FM
TO
High pressure sensor
SV2
Accumulator
SV
Oil
SV42
SV3C
SV
TD2 TD3
HP HP
TK4 HP
SW
SW
SW
Comp.
Comp.
2 3
TK1 TK2 TK3
SV3F
TK5
SV
SV3A
SV3B
SV
Balance pipe
Liquid pipe
Dischage gas pipe
Suction Gas pipe
Unit
receiving oil
∗
)
PMV1 PMV2
TE2
4-way
valve
Low pressure
TS1
sensor
TL
TS2
FP
FP
SV43
Liquid tank
SV
SV1
Check joint
(Liquid)
– 68 –
Follower unit (MMY-MAP0724FT
FM
PMV4
TE1
SV11
SV
SV5
SV
SV6
High pressure sensor
SV3D
Oil
separator
SV
SV41
SV3C
SV
TD1
HP TK4
SW
Comp.
1
TK1
Oil header
TK5
SV3E
SV3A
∗
)
TO
4-way
valve
TS1
Low
pressure
TS2
FP
SV2
Accumulator
SV
SV42
SV
TD2
HP
SW
Comp.
2
TK2
SV3B
SV