Major Functional Parts - Daikin FTX25JVEA9 Service Manual

Refrigerant System and Function of Functional Parts of Outdoor Unit
1.2

Major Functional Parts

104
Compressor : JT100F-VD
The application of Inverter drive enables the capacity control for 1 Hz/step at 25 to 98Hz in
cooling operation or at 30 to 105Hz in heating operation.
Oil separator
Collects oil discharged from the compressor. The oil discharged passes through filter,
capillary tube and accumulator to return to the compressor.
4-way valve
Carries out switching of the cooling/heating operations.
EVP : Discharge to Suction bypass motorized valve
Motorized valve for capacity control.
[When small-capacity indoor unit is operating, opens to activate the high pressure rising
protection function (in heating operation) or the freeze protection function (in cooling
operation)]
EVL : Liquid pipe motorized valve
In cooling operation, it judges based on outdoor unit's SC control whether there is surplus
refrigerant or not, and EVL opens or closes to adjust the surplus refrigerant amount in the
receiver.
In heating operation, if EVG is opened, when the surplus refrigerant is in receiver the entire
system control is provided.
EVG : Gas pipe motorized valve
In cooling operation, if EVL is opened, when the surplus refrigerant is in receiver the entire
system control is provided. In heating operation, if surplus refrigerant treatment is required
(the opening of EVT is minimum), feed the surplus refrigerant in the receiver with reverse
discharge pipe temperature control. If small-capacity indoor unit is connected and the high
pressure rises, open the EVG to increase auxiliary heat exchanger capacity and decrease
the high pressure.
Outdoor unit fan
The upper limit of the fan speed is provided to secure the differential pressure in low-
temperature cooling operation. The fan runs with H-tap in overloaded cooling and low-
temperature heating. For other cases the fan runs with L-tap.
Capillary tube for gas purge
When the unit is operated in pump down mode, this tube serves as gas purging capillary
tube.
Check valve
When the liquid refrigerant in the receiver overflows, flows the liquid refrigerant to accelerate
the evaporation in cooling operation, or prevent the liquid refrigerant from intrusion into the
receiver in heating operation.
Check valve
When the liquid refrigerant in the receiver overflows, prevents the liquid refrigerant from
flowing into the suction pipe in cooling operation, or prevent the liquid refrigerant from EVL
from flowing into the discharge side when heating.
Cooling piping
When EVP is open, cools the discharged gas once and protects the EVP from abnormal
high temperature.
EVU : Motorized valve in operating room BP unit
When EVL opens in cooling operation, activates SH control to carry out self-determination of
the refrigerant control in BP unit. When EVL is closed, carries out the entire system control
and distribution control (gas pipe isothermal control). In heating operation, carries out the
controls equal to Super-multi unit control (entire system control and SC control).
Si18-201
Main Functions