Carrier 48PG16 User Manual
Gas Heating/Electric Cooling
Single Package Rooftop Units
High Altitude Kit Accessory
Installation Instructions
Part No. CRNGHIAT002A00
HIGH ALTITUDE KIT USAGE AND CONTENTS
ACCESSORY PART NO. USAGE CONTENTS
CRNGHIAT002A00 48PG16
9 Burner Orifices, Drill Size No. 31, 0.120 in.
9 Burner Orifices, Drill Size No. 32, 0.116 in.
48PG16
SAFETY CONSIDERATIONS
Read these instructions entirely before installing the acces-
sory high altitude kit into the base rooftop unit.
Installation, start-up, and servicing of this equipment can be
hazardous due to system pressures, electrical components, and
equipment location (roofs). Only trained, qualified installers
and service technicians should install, start up, and service this
equipment.
When working on this equipment, observe precautions in
the literature and on tags, stickers, and labels attached to the
equipment. Also observe any other safety precautions that may
apply.
Before beginning any modification, close main gas supply
shutoff valve. Be certain that the main line electrical disconnect switch is in the OFF position and lockout tag is
installed. Electric shock or fire could result. Tag disconnect
switch and gas valve with suitable warning labels.
GENERAL
The high altitude conversion kit is used to install natural gas
units at elevations as high as 7000 ft. Recommended orifice
sizes will derate the heating input by approximately 4% per
1000 ft of elevation. For elevations above 7000 ft, see Table 1.
INSTALLATION
Step 1 — Remove Gas Manifold Pipe
1. Close the manual shutoff valve on the gas supply
piping.
2. Open gas section access door. See Fig. 1.
3. Set the switch on the main gas valve to the OFF position. See Fig. 2.
4. Shut off power to unit and install lockout tag.
5. Disconnect gas piping at unit gas valve.
NOTE: Use a backup wrench to avoid twisting the gas
manifold pipe.
6. Remove wires connected to gas valve. Mark each wire
to ensure proper reassembly.
7. Remove wires connected to the flame rollout switch.
Mark wires.
8. Remove wires connected to igniter and flame sensor.
Mark wires.
9. Remove the four screws that attach the gas manifold
pipe to the burner bracket and rotate the pipe away
from the unit. The pipe should NOT be removed from
the wire bundle connecting to the IGC (integrated gas
controller) board. See Fig. 3.
Table 1 — Altitude Compensation*
ELEVATION
(ft)
0-1,999 30
2,000 30
3,000 31
4,000 31
5,000 31
6,000 31
7,000 32
8,000 32
9,000 32
10,000 35
11,000 36
12,000 37
13,000 38
14,000 39
*As the height above sea level increases, there is less oxygen per cubic foot
of air. Therefore, heat input rate should be reduced at higher altitudes.
Includes a 4% input reduction per each 1000 ft.
†Orifices available through your Carrier dealer.
48PG16
NATURAL GAS
ORIFICE†
Step 2 — Replace Orifice Fittings
1. Remove standard orifice fittings from the manifold
pipe.
2. Select the correct orifice size based on local elevation.
Refer to Table 1.
3. Install new orifice fittings.
NOTE: Pipe sealant is not required. Never use Teflon
tape on fitting threads since loose pieces may plug gas
orifices.
Step 3 — Reinstall Manifold Pipe
1. Attach manifold pipe to the burner bracket using four
screws. See Fig. 3. Make sure that all orifice fittings
are properly seated in the burner inlets.
2. Reconnect wires to the igniter, flame sensor, flame
rollout switch, and gas valve.
3. Reconnect gas piping to the gas valve.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Ta b 1 a 6 a
Catalog No. 04-53480022-01 Printed in U.S.A. Form 48PG-21SI Pg 1 12-05 Replaces: New
ECONOMIZER HOODS
OUTDOOR AIR
SCREENS
(HIDDEN)
CONDENSER
COIL ACCESS
PAN EL
BAROMETRIC
RELIEF DAMPER
HOODS
ELECTRICAL
OPTIONS
PAN EL
HEAT
EXCHANGER
SECTION
COMBUSTION
FAN HOUSING
MAIN
BURNER
SECTION
Fig. 2 — Typical Gas Heating Section
FILTER
ACCESS DOOR
BASEPAN
CONNECTIONS
ACCESS PANEL
CONTROL BOX
AND COMPRESSOR
ACCESS DOOR
Fig. 1 — Panel and Filter Locations
4. Set the switch on the main gas valve to the ON position.
5. Call for high stage heat (W2 energized). The unit may
require several ignition attempts due to trapped air in
the manifold pipe.
6. When main burners ignite check orifice fittings for
leaks. Repair if necessary.
INDUCED
DRAFT
MOTOR
Never use a match or other open flame to check for leaks.
Use a soap and water solution. Fire or serious injury could
result.
MAIN GAS
VALV E
If unit is equipped with a 2-stage gas valve, ensure valve
has energized second stage (high fire) before adjusting
manifold pressure. Improper manifold pressures may cause
explosion or injury.
7. Verify that manifold pressure is between 2.7 and
3.0 in. wg while in high fire (W2 energized). Readjust
pressure if necessary.
GAS SECTION
ACCESS DOOR
Step 4 — Check Unit Operation and Make
Necessary Adjustments
NOTE: Gas pressure must not be less than 5 in. wg or greater
than 13 in. wg at the unit connection.
1. Remove pressure tap plug from manifold pipe and
connect a pressure gage or manometer.
2. Turn on electrical supply.
3. Open the manual shutoff valve on the gas supply piping. Check pipe connection to main gas valve for
leaks.
This unit is designed to operate at 3.0 in. wg (± 0.3 in. wg)
manifold pressure at high fire. Exceeding this pressure will
cause explosion or injury.
8. Shut down unit by turning down thermostat (units with
electro-mechanical control) or putting unit in Service
Test mode (units with ComfortLink™ control), shutting off manual gas valve, and shutting down power to
unit.
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