5750156-UIM-B-0919
10
Johnson Controls Ducted Systems
• The unit and its equipment shutoff valve must be disconnected
from the gas supply system during any pressure testing of that
system at test pressures in excess of 1/2 psi (3.48 kPa).
• The unit must be isolated from the gas supply piping system by
closing its individual manual shut-off valve before conducting any
pressure testing of the gas supply piping system at test pressures
equal to or less than 1/2 psig (3.48 kPa).
HIGH ALTITUDE GAS CONVERSION
This furnace is constructed at the factory for natural gas-fired operation
at altitudes up to 2,000 ft above sea level. For installations located
above 2,000 ft, the gas input rate to the burners must be reduced by 4%
per 1,000 ft above sea level. It may be necessary to change to smaller
orifices at high altitude. See the table below for the correct orifice size to
use.
FLUE VENT AND AIR INTAKE HOOD
The flue vent hood and air intake hoods are shipped loose. These
hoods must be installed to ensure proper unit operation. The hoods
must be fastened to the outside of the side gas control/electrical com-
partment with the screws provided. See Figure 8.
WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result in serious
injury, death or property damage.
Never test for gas leaks with an open flame. use a commercially
available soap solution made specifically for the detection of leaks to
check all connections. A fire or explosion may result causing property
damage, personal injury or loss of life.
!
Table 10:
High Altitude Gas Orifice Sizing
Elevation Above Sea Level (ft)
Gas Type
Cabinet
Size
0–2000
(Factory)
2001–
3000
3001–
4000
4001–
5000
5001–
6000
6001–
7000
7001–
8000
8001–
9000
9001–
10000
Natural Gas Orifice Sizes
B
36
37
38
38
39
40
41
41
42
A
42
42
43
43
43
44
44
45
46
LP Gas Orifice Sizes
B
51
51
52
52
52
52
53
53
53
A
54
54
55
55
55
55
55
56
56
WARNING
Flue hood surfaces may be hot.
CAUTION
The flue exhaust hood must be properly installed and within the rec-
ommended clearances. Further communications and action must be
given to the home or building owner(s) to eliminate any unauthorized
human contact around this area during the heating cycle. Flue hood
surfaces and the immediate area reach high temperatures during the
heating cycle.
!
!
FIGURE 8:
Flue Vent Outlet Air Hood
AIR INTAKE HOOD
AIR INTAKE SCREEN
EXHAUST HOOD
A0284-001
Table 11:
Natural Gas Application Data - PCG4
Available on Models
Input (MBH)
1
High Fire
1. Heating capacity valid for elevations up to 2000 ft above sea level. For elevations above 2,000 ft, rated capacity must be reduced by 4% for each 1,000 ft above
sea level.
Output (MBH)
High Fire
Gas Rate
2
Cubic Feet per Hour
High Fire/Low Fire
2. Based on 1075 BTU/ft
3
.
Number of
Burners
Temperature Rise ºF
at Full Input
3
3. The airflow must be adequate to obtain a temperature rise within the range shown. Continuous return air temperature must not be below 55°F.
Minimum Maximum
2, 2-1/2 Tons
50
41
46
2
40
70
3 Tons
50
41
46
2
35
65
4, 5 Tons
65
53
60
2
40
70
2, 2-1/2, 3, 3-1/2 Tons
75
61
70
3
40
70
3, 3-1/2 Tons
100
81
93
4
40
70
4, 5 Tons
100
81
93
3
40
70
4, 5 Tons
125
101
116
4
40
70