Carrier Performance 48VR-A Manual de instrucciones descargar pdf (Pagina 27)

Normal Operation

An LED (light--emitting diode) indicator is provided on the

integrated gas unit controller (IGC) to monitor operation. The IGC

is located by removing the control access panel (see Fig. 20).

During normal operation, the LED is continuously on (See Table 6

for error codes).

Airflow and Temperature Rise

The heating section for each size unit is designed and approved for

heating operation within the temperature--rise range(s) stamped on

the unit rating plate.

Tables 10 show the approved temperature rise range for each

heating input and stage, and the air delivery cfm at various

temperature rises for a given external static pressure. The heating

operation airflow must produce a temperature rise that falls within

the approved range for each heating stage.

Refer to Indoor Airflow and Airflow Adjustments section to adjust

heating airflow when required.

Gas Heating Sequence of Operation

(See Fig. 14, 16, 17 and unit wiring label.)

On a call for low stage heating, terminal W1 on the thermostat is

energized. On a call for high stage heating both terminals W1 and

W2 are energized. Regardless of the stage of the heating call, the

induced--draft motor is turned on to high speed for a 15 sec

pre--purge time. After the pre--purge, when the pressure switch

senses that sufficient combustion air is being moved by the

induced--draft motor, the ignition sequence begins. The IGC will

energize the sparker and the low stage gas valve solenoid. Upon

sensing flame, the IGC will check the heating call. If W2 is not

energized, the IGC will drop the induced--draft motor to low speed

and maintain the gas valve on low stage. If W2 is energized, the

IGC will maintain the induced--draft motor on high speed and

energize the high stage gas valve solenoid. Thirty sec after flame is

sensed the IGC will turn on the evaporator fan motor. If W2 is not

energized, the evaporator fan motor will run on low heat speed. If

W2 is energized, the evaporator fan motor will run on high heat

speed. After the call for heat is satisfied, the IGC will run the

evaporator fan motor an additional field--selectable time of 90, 120,

150, or 180 sec before shutting the evaporator fan motor off.

Limit Switches

Normally closed limit switch(es) (LS) complete the control circuit.

Should the leaving--air temperature rise above the maximum

allowable temperature, the limit switch opens and the control

circuit “breaks.” Any interruption in the control circuit instantly

closes the gas valve and stops gas flow to the burners. The blower

motor continues to run until LS resets.

When the air temperature at the limit switch drops to the

low--temperature setting of the limit switch, the switch closes and

completes the control circuit. The direct--spark ignition system

cycles and the unit returns to normal heating operation.

Table 6 – LED Indications

STATUS CODE LED INDICATION

Normal Operation

No Power or Hardware Failure Off

Limit Switch Fault 2 Flashes

Flame Sense Fault 3 Flashes

Four Consecutive Limit Switch Faults 4 Flashes

Ignition Lockout Fault 5 Flashes

Pressure Switch Fault 6 Flashes

Rollout Switch Fault 7 Flashes

Internal Control Fault 8 Flashes

Temporary 1 hr auto reset

9 Flashes

NOTES:

1.This code indicates an internal processor fault that will reset itself in one

hr. Fault can be caused by stray RF signals in the structure or nearby. This

is a UL requirement.

2. LED indicates acceptable operation. Do not change ignition control

board.

3. When W is energized the burners will remain on for a minimum of 60 sec.

4.IfmorethanoneerrorcodeexiststheywillbedisplayedontheLEDin

sequence.

Rollout Switch

The function of the rollout switch is to close the main gas valve in

the event of flame rollout. The switch is located above the main

burners. When the temperature at the rollout switch reaches the

maximum allowable temperature, the control circuit trips, closing

the gas valve and stopping gas flow to the burners. The indoor

(evaporator) fan motor (IFM) and induced draft motor continue to

run until switch is reset. The IGC LED will display FAULT CODE

Step 3 — Start--up Cooling and Make Adjust-

ments

Complete the required procedures given in the Pre--Start--Up

section before starting the unit. Do not jumper any safety devices

when operating the unit. Do not operate the compressor when the

outdoor temperature is below 40F(4.4C) (unless accessory

low--ambient kit is installed). Do not rapid--cycle the compressor.

Allow 5 minutes between on cycles to prevent compressor damage.

Checking Cooling Control Operation

Start and check the unit for proper control operation as follows:

1. Place room thermostat SYSTEM switch or MODE control

in OFF position. Observe that blower motor starts when

FAN mode is placed in FAN ON position and shuts down

when FAN MODE switch is placed in AUTO position.

2. Thermostat:

On a typical two stage thermostat, when the room temper-

ature rises 1 or 2 degrees above the cooling control setting

of the thermostat, the thermostat completes the circuit

between thermostat terminal R and terminals Y1, O and G.

These completed circuits through the thermostat connect the

contactor coil (C) (through unit wire Y1) and indoor fan

board (through unit wire G) across the 24--v. secondary of

transformer (TRAN).

On a typical two stage thermostat, when the room temperat-

ure is several degrees above the cooling control setting of

the thermostat, the thermostat completes the circuit between

terminal R and terminals Y1, Y2, O and G.

3. When using an automatic changeover room thermostat

place both SYSTEM or MODE control and FAN mode

stitches in AUTO positions. Observe that unit operates in

Cooling mode when temperature control is set to “call for

Cooling” (below room temperature).

NOTE: Once the compressor has started and then has stopped, it

should not be started again until 5 minutes have elapsed.

IMPORTANT: Three--phase, scroll compressors are direction

oriented. Unit must be checked to ensure proper compressor

3--phase power lead orientation. If not corrected within 5 minutes,

48VR-- A

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Carrier Performance 48VR-A Manual de instrucciones Pagina 27

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