Carrier Supra 650 Service Manual download pdf (Page 47)

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3.1.8 Auto Diesel Restart (Option)

If AC power is lost for five minutes or more, configuration

10 is active and TIME START is enabled, the diesel

engine will start and run until AC power is restored and

applied for five minutes. When the five minute shutdown

timer expires and AC power is present, the unit will shut

down the diesel engine and restart the standby motor. If

AC power is NOT present, the diesel engine will operate

as required.

Once the unit has cycled off, it will remain off for the

minimum off time of five minutes. This prevents rapid

cycling due to changes in air temperature. Air tempera-

ture in the box changes rapidly but it takes time for the

product temperature to change.

3.2 SEQUENCE OF OPERATION

3.2.1 Engine Drive

Refer to SECTION 6 for a schematic diagram of the unit

controls. To facilitate location of the components re-

ferred to in the written text, the schematic has map

coordinates added to the margins. These locations

have also been added to the legend. In order to provide

complete information, the following description is writ-

ten as if all options are installed. Indications of specific

unit applicability and optional equipment are provided

on the schematic diagram. The microprocessor controls

operation of the various relays and components by com-

pleting or by breaking the circuit to ground.

To start the unit, place the the RUN/STOP Switch ( RSS)

in the RUN position and the cab command I/O Switch in

the ON position. Operation of the control circuit is the

same for microprocessor or manual start except on

units equipped with a Manual Glow/Crank Switch

(MGC), the operator may use that switch to energize the

glow plugs and crank the engine.

With the switches positioned, the ROAD key is pressed

to begin the start process. Power flows from RSS

through fuse F2 to the Run Control Relay (RCR). RCR is

grounded by the microprocessor through the Door

Switch Relay (DSR) and cab command to energize

RCR. The RCR contacts close to provide power to the

control relays. Power to the Run Relay (RR) is depen-

dent on the High Pressure Switch (HPS) being closed. If

the high pressure switch is open, power will not be ap-

plied to microprocessor terminal M1 and operation will

not be allowed.

Energizing RR closes a set of contacts to supply power

to the alternator (ALT), Run Solenoid (RS), Fuel Pump

(FP) and Fuel Heater Relay (FHR). RS energizes to

open the engine fuel rack, FP energizes to pump fuel to

the injection pump and FHR energizes to close a set of

contacts supplying power to the fuel heater thermostat.

The fuel heater thermostat closes to energize the fuel

heater at temperatures below the option setting. The

engine is thus prepared for start up.

The microprocessor will now run the Auto Start Se-

quence (refer to Section 3.2.3) to start the engine. The

Glow Plug Relay (GPR) is energized to close a set of

contacts (SSC) and provide power to the Glow Plugs

(GP) as required to preheat the engine cylinders. The

Starter Solenoid Relay (SSR) will then be energized to

close a set of contacts and energize the Starter Sole-

noid (SS). Energizing SS closes a set of contacts to

energize the Starter Motor (SM) and crank the engine.

During cranking a signal is also supplied to microproces-

sor terminal L2. Once the engine starts and and the

alternator begins to produce power, the microprocessor

senses the power at terminal L3 and the start sequence

is terminated. The microprocessor ignores the Oil Pres-

sure Switch (OP) signal for 15 seconds to allow the

engine time to develop sufficient pressure to close OP.

The unit will start in High Speed Heat with unloaders

energized (850 and 950) and fans de--energized. After

30 seconds the unit will revert to normal temperature

control.

Once the engine has started, the microprocessor will

complete the Defrost Transistor (DT) circuit to energize

the Electric Fan Motor Relays (EFMR 1 through 3)

which close contacts to energize the Electric (Evapora-

tor) Fan Motors (EFM1 through 3).

The microprocessor continues to monitor inputs to de-

termine required modes of operation. The inputs include

the Suction Pressure Transducer (SPT), Water temper-

ature Sensor, Supply Air Sensor (SAS), and the Com-

pressor Discharge Transducer (CDT).

As required, the microprocessor will take the following

actions:

On Supra 850 and 950 units, when in the low speed

mode, the microprocessor also energizes the Unloader

Front Relay (UFR). Energizing UFR closes a set of

contacts to energize the compressor unloader (UF) de-

activating two cylinders.

For high ambient protection on Supra 850 units, the

unloader is controlled through the Compressor Clutch

Relay (CCR). CCR is energized through a second dis-

charge pressure switch (HP2). If high pressure is below

367 psig (25 bar) the compressor is in 4 cylinder opera-

tion (2 cylinder for 950). If pressure is above 440 psig (30

Bar) the compressor is in 4 or 6 cylinder operation.

On call for heat, the Heater Relay (HR1) is energized to

close a set of contacts and energize the hot gas bypass

olenoid valve (HGS2) and the hot gas valve (HGS1)

placing the unit in the heat mode. If the unit is equipped

with hot water heat, the contactor will open the hot water

heat solenoid valve. Units equipped with electric heat

will energize the heater elements.

On call for defrost, the microprocessor energizes the hot

gas bypass valve (HGS2) and the hot gas valve (HGS1)

in the same manner as in heat. Also, DT is de--ener-

gized, stopping the evaporator fan motors.

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Comments to this Manuals

Hermes Hurtado 13 Mar 2025 | 11:43:58

Soy mecánico mantenedor. Necesito manuales técnicos

Carrier Supra 650 Service Manual Page 47

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