9
3. Use #18 AWG wire for 24V control wiring runs not
exceeding 75 feet. Use #16 AWG wire for 24V control wiring
runs not exceeding 125 feet. Use #14 AWG wire for 24V
control wiring runs not exceeding 200 feet. Low voltage
wiring may be National Electrical Code (NEC) Class 2 where
permitted by local codes.
4. Route thermostat wires from sub-base terminals to the
unit. Control wiring should enter through the condenser
panel opening or through curb indicated in “Electrical
Entrance” figure. Connect thermostat and any accessory
wiring to low voltage terminal block TB1 in the main control
box.
NOTE:
Field-supplied conduit may need to be installed depending
on unit/curb configuration. Use #18 AWG solid conductor wire
whenever connecting thermostat wires to terminals on sub-base.
DO NOT use larger than #18 AWG wire. A transition to #18 AWG
wire may be required before entering thermostat sub-base.
NOTE: Refer to unit wiring diagrams for thermostat hookups.
GAS SUPPLY PIPING
T
O
PREVENT
PERSONAL
INJURY
OR
DEATH
DUE
TO
IMPROPER
INSTALLATION
,
ADJUSTMENT
,
ALTERATION
,
SERVICE
OR
MAINTENANCE
,
REFER
TO
THIS
MANUAL
. F
OR
ADDITIONAL
ASSISTANCE
OR
INFORMATION
,
CONSULT
A
QUALIFIED
INSTALLER
,
SERVICE
AGENCY
OR
THE
GAS
SUPPLIER
.
WARNING
IMPORTANT NOTE:
This unit is factory set to operate on natural
gas at the altitudes shown on the rating plate.
T
O
AVOID
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
WHEN
EITHER
USING
PROPANE
GAS
ALONE
OR
AT
HIGHER
ALTITUDES
,
OBTAIN
AND
INSTALL
THE
PROPER
CONVERSION
KIT
(
S
). F
AILURE
TO
DO
SO
CAN
RESULT
IN
UNSATISFACTORY
OPERATION
AND
/
OR
EQUIPMENT
DAMAGE
. H
IGH
ALTITUDE
KITS
ARE
FOR
U.S.
I
NSTALLATIONS
ONLY
AND
ARE
NOT
APPROVED
FOR
USE
IN
C
ANADA
.
WARNING
The rating plate is stamped with the model number, type of gas
and gas input rating. Make sure the unit is equipped to operate on
the type of gas available. Conversion to propane (LP) gas is permit-
ted with the use of the factory authorized conversion kit (see the
unit Technical Manual for the appropriate kit). For High Altitude
derates, refer to the latest edition of the National Fuel Gas Code
NFPA 54/ANSI Z223.1.
NATURAL
Min. 5.0" W.C., Max. 10.0" W.C.
PROPANE
Min. 11.0" W.C., Max. 14.0" W.C.
INLET GAS PRESSURE
Inlet Gas Pressure Must Not Exceed the Maximum Value Shown in Table Above.
The minimum supply pressure should not vary from that shown in
the table above because this could prevent the unit from having
dependable ignition. In addition, gas input to the burners must
not exceed the rated input shown on the rating plate. Overfiring
of the unit could result in premature heat exchanger failure.
P
IPING
IMPORTANT NOTE:
To avoid possible unsatisfactory operation or
equipment damage due to under firing of equipment, do not un-
dersize the natural/propane gas piping from the meter/tank to the
unit. When sizing a trunk line, include all appliances on that line
that could be operated simultaneously.
The rating plate is stamped with the model number, type of gas
and gas input rating. Make sure the unit is equipped to operate on
the type of gas available. The gas line installation must comply
with local codes, or in the absence of local codes, with the latest
edition of the National Fuel Gas Code NFPA 54/ANSI Z223.1.
Natural Gas Connection
1/2
3/4
1
1 1/4
1 1 /2
10
132
278
520
1050
1600
20
92
190
350
730
1100
30
73
152
285
590
980
40
63
130
245
500
760
50
56
115
215
440
670
60
50
105
195
400
610
70
46
96
180
370
560
80
43
90
170
350
530
90
40
84
160
320
490
100
38
79
150
305
460
Pressure= .50 PSIG or less and Pressure Drop of 0.3" W.C.
(Based on 0.60 Specific Gravity Gas)
Natural Gas Capacity of Pipe
in Cubic Feet of Gas Per Hour (CFH)
Nominal Black Pipe Size (inches)
Length of
Pipe in Feet
Heating Value of Gas (BTU/Cubic Foot
CFH =
BTUH Furnace Input
Refer to the Proper Piping Practice drawing for the general layout
at the unit. The following rules apply:
1. Use black iron pipe and fittings for the supply piping. The
use of a flex connector and/or copper piping is permitted
as long as it is in agreement with local codes.
2. Use pipe joint compound on male threads only. Pipe joint
compound must be resistant to the action of the fuel used.
3. Use ground joint unions.
4. Install a drip leg to trap dirt and moisture before it can
enter the gas valve. The drip leg must be a minimum of
three inches long.
5. Use two pipe wrenches when making connection to the
gas valve to keep it from turning.
6. Install a manual shut-off valve in a convenient location
(within six feet of unit) between the meter and the unit.
7. Tighten all joints securely.
8. The unit must be connected to the building piping by one
of the following methods:
• Rigid metallic pipe and fittings
