IX.
VENTING
Refer to the enclosed Installation Instructions, (Vent Tables For 1-
and 2-Stage Category I Fan-Assisted Furnaces) for quick, easy
reference, and national or local installation code such as National
Fuel Gas Code NFPA 54-1999/ANSI Z223.1-1999 in the United
States, or the National Standard of Canada Natural and Propane
Installation Codes CAN/CGA-B149.1- and .2-M95 in Canada, for
proper vent sizing and installation requirements.
After fully assembling the vent connector to the furnace flue
collar, securely fasten the vent connector to the collar with 2
field-supplied, corrosion-resistant, sheet metal screws located
180 degrees apart and midway up the collar.
The horizontal portion of the venting system shall maintain a
minimum of 1/4-in. upward slope per linear ft, and it shall be
rigidly supported every 5 ft or less with hangers or straps to
ensure that there will be no movement after installation.
X.
START-UP, ADJUSTMENT, AND SAFETY CHECK
A.
General
The furnace must have a 115-v power supply properly connected
and grounded. Correct polarity must be maintained to enable gas
heating operation.
The gas service pressure must not exceed 0.5 psig (14-in. wc), and
no less than 0.16 psig (4.5-in. wc).
Thermostat wire connections at R and W/W1 are the minimum
required for gas heating operation. W2 must be connected for
2-stage heating thermostats. C
OM
, Y/Y2, and G are required for
cooling, heat pumps, and some clock thermostats. These must be
made at the 24-v terminal block on the control. (See Fig. 11.)
This furnace can be installed with either a single-stage heating or
a 2-stage heating thermostat.
For single-stage thermostats, connect thermostat W to W/W1 at
furnace control terminal block. (See Fig. 9.) For single-stage
thermostats, the control will determine, based on length of previ-
ous heating on and off cycles, when to operate in low- and
high-gas heat for optimum comfort. Setup switch-2 (SW-2) must
be in the factory-shipped OFF position. See Fig. 12 and Tables 6
and 7 for setup switch information.
If a 2-stage heating thermostat is to be used, move SW-2 to ON
position at end of furnace installation. This overrides built-in
control process for selecting high and low fire and allows the
Fig. 10—Heating and Cooling Application Wiring Diagram 2-Stage Thermostat and Condensing Unit
A99072
115-V FUSED
DISCONNECT
SWITCH
(WHEN REQUIRED)
JUNCTION
BOX
CONTROL
BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-
ONLY
SEVEN
WIRE
2-STAGE THERMOSTAT TERMINALS
FIELD-SUPPLIED
FUSED DISCONNECT
2-SPEED
CONDENSING
UNIT
FURNACE
G
R
W2
Y2
G
Y1
C
GND
GND
GND
GND
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
Y2
Y1
C
WHT
BLK
WHT
BLK
W1
R
W2
COM
W/W1
Y/Y2
NOTES:
1. Connect Y-terminal as shown for proper operation.
2. Some thermostats require a "C" terminal connection as shown.
3. If any of the original wire, as supplied, must be replaced,
use same type or equivalent wire.
TABLE 6—SETUP SWITCH DESCRIPTION
SETUP
SWITCH NO.
NORMAL
POSITION
DESCRIPTION
OF USE
SW-1
Only High-Gas Heat
OFF (Staged Gas
Heat)
Turn switch on to obtain only high-gas-heat operation on any call
for heat regardless of whether R-W/W1, or R-W/W1, -W2 is
closed. SW-1 overrides SW-2.
SW-2
Low-Gas Heat (Adaptive Mode)
OFF (Single-Stage Thermostat)
Turn switch off for installations with single-stage thermostats; con-
trol selects low-gas-heat or high-gas-heat operation based on pre-
vious cycles. Turn switch on for installations with 2-stage thermo-
stats to permit only low-gas-heat operation in response to closing
R-W/W1. High-gas heat is supplied only when R to W/W1 and W2
are closed.
SW-3 and SW4
ON, OFF
Switches control gas heating mode blower off delay. (See Table
7.)
TABLE 7—BLOWER OFF DELAY SETUP
SWITCH (SW) POSITION
DESIRED HEATING
MODE BLOWER OFF
DELAY (SEC)
SETUP SWITCH
SW-3
SW-4
90
OFF
OFF
135
OFF
ON
180
ON
OFF
225
ON
ON
—10—