Discharge Temperature Control; Pulse Modulating Valve (P .M.v.) Control - Carrier 42cvur018-703 Service Manual

Item

10. Discharge temperature control

Td value
Judges as an error and stops the compressor.
117°C
Reduce the compressor speed.
112°C
Reduce slowly compressor speed.
108°C
Keeps the compressor speed.
105°C
If the operation is performed with lower speed than one
commanded by the serial signal, speed is slowly raised
up to the commanded speed.
98°C
Operates with speed commanded by the serial signal.
11. Pulse This function controls throttle amount of the
Modulating refrigerant in the refrigerating cycle.
valve (P.M.V.)
According to operating status of the air conditioner,
control
this function also controls the open degree of valve
with an expansion valve with pulse Modulation.
initial position
SH control
PMV open degree control
Stop by
remote controller
Power OFF
* SH (Super Heat amount) =
Ts (Temperature of suction pipe of the compressor) –
Tc (Heat exchanger temperature at evaporation side)
* PMV: Pulse Modulating Valve
Operation flow and applicable data, etc.
Control operation
Starting up
Initialize
Move to
Compressor ON
Td
release control
Room temp. sensor
(Ta sensor) control
1. Purpose
This function detects error on the
refrigerating cycle or error on the com-
pressor, and performs protective control.
2. Operation
• Control of the compressor speed
The speed control is performed as
described in the left table based upon
the discharge temperature.
1) When starting the operation, move the
valve once until it fits to the stopper.
(Initialize)
* In this time, "Click" sound may be
heard.
2) Adjust the open degree of valve by super
heat amount. (SH control)
3) If the discharge temperature was exces-
sively up, adjust the open degree of valve
so that it is in the range of set tempera-
ture.
(Discharge temp. control)
4) To turn off the compressor while the air
conditioner stops by control of the
thermostat or by remote controller, adjust
the open degree of valve to the setup
value before stop of the compressor.
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32
FILE NO. SVM-12052
Description