Controls, Start-Up, Operation, Service and ... - Climayoreo

Gas System Adjustment (48P Only)
GAS VALVE ADJUSTMENT — The gas valve opens and
closes in response to the unit control.
When power is supplied to valve terminals D1 and C2, the
main valve opens to its preset position.
The regular factory setting is stamped on the valve body
(3.3 in. wg).
To adjust regulator:
1. Set thermostat at setting for no call for heat.
2. Switch main gas valve to OFF position.
3. Remove 1/ 8-in. pipe plug from manifold or gas valve
pressure tap connection. Install a suitable pressuremeasuring
device.
4. Switch main gas valve to ON position.
5. Set thermostat at setting to call for heat.
6. Remove screw cap covering regulator adjustment
screw (see Fig. 90).
7. Turn adjustment screw clockwise to increase pressure
or counterclockwise to decrease pressure.
8. Once desired pressure is established, set thermostat
setting for no call for heat, turn off main gas valve,
remove pressure-measuring device, and replace 1 / 8-in.
pipe plug and screw cap.
MAIN BURNERS — For all applications, main burners are
factory set and should require no adjustment.
MAIN BURNER REMOVAL AND REPLACEMENT
1. Shut off (field-supplied) manual main gas valve.
2. Shut off power to unit.
3. Remove gas section access door, door frame, and corner
post.
4. Disconnect gas piping from gas valve inlet.
5. Remove wires from gas valve.
6. Remove wires from rollout switch.
7. Remove sensor wire and ignitor cable form IGC board.
8. Remove 2 screws securing manifold bracket to basepan.
9. Remove 2 screws that hold the burner support plate
flange to the vestibule plate.
10. Lift burner assembly out of unit.
11. Replace burner assembly. Reinstall by reversing Steps 1
to 10.
INLET PRESSURE
TAP (ON SIDE)
1/8-IN. 27 NPT
LOW-FIRE REGULATOR
ADJUSTMENT SCREW
Fig. 90 — Gas Valve
OUTLET PRESSURE
TAP (ON SIDE)
1/8-IN. 27 NPT
HIGH-FIRE REGULATOR
ADJUSTMENT SCREW
163
Moisture/Liquid Indicator — A clear flow of liquid
refrigerant indicates sufficient charge in the system. Bubbles
indicate undercharged system or the presence of noncondensables.
Moisture in the system measured in parts per million
(ppm) changes the color of the indicator:
Green — moisture below 45 ppm (dry)
Chartreuse — 45 to 130 ppm (caution!)
Yellow — moisture above 130 ppm (wet)
Change filter driers at the first sign of moisture in the system.
See Carrier Charging Handbook for more information.
IMPORTANT: Unit must be in operation at least
12 hours before moisture indicator can give an accurate
reading. With unit running, indicating element must be
in contact with liquid refrigerant to give a true reading.
Filter Drier — Replace whenever the moisture/liquid indicator
shows moisture in the system.
Liquid Line Service Valves — Use caution when
closing liquid line service valves. The expansion of a trapped
liquid can create dangerously high pressures. Remove refrigerant
immediately from trapped sections or attach a hose from
the high side to the low side of the system to provide relief. If
equipped with a liquid line solenoid valve in the evaporator
section, it will be closed during the off-cycle. This creates the
potential for a liquid trap between the solenoid valve and a
closed service valve. Remove refrigerant immediately from the
section or attach a hose for relief.
Protective Devices
COMPRESSOR PROTECTION
Overcurrent — Each compressor has one manual reset,
calibrated trip, magnetic circuit breaker. Do not bypass connections
or increase the size of the circuit breaker to correct trouble.
Determine the cause and correct it before resetting the
breaker.
Overtemperature — Each compressor has a protector to protect
it against excessively high discharge gas temperatures.
Additionally, some units contain Copeland compressors
equipped with advanced scroll temperature protection (ASTP).
A label located above the terminal box identifies Copeland
Scroll compressor models that contain this technology. See
Fig. 91. Advanced scroll temperature protection is a form of internal
discharge temperature protection that unloads the scroll
compressor when the internal temperature reaches approximately
300 F. At this temperature, an internal bi-metal disk
valve opens and causes the scroll elements to separate, which
stops compression. Suction and discharge pressures balance
while the motor continues to run. The longer the compressor
runs unloaded, the longer it must cool before the bi-metal disk
resets. See Fig. 92.
To manually reset ASTP, the compressor should be stopped
and allowed to cool. If the compressor is not stopped, the motor
will run until the motor protector trips, which occurs up to
90 minutes later. Advanced scroll temperature protection will
reset automatically before the motor protector resets, which
may take up to 2 hours.