Installation Manual

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Specifications are subject to change without notice.
j. Move setup switch SW1--2 to off position after com-
pleting low--heat adjustment.
k. Leave manometer or similar device connected and
proceed to Step 4.
4. Adjust manifold pressure to obtain high fire input rate.
(See Fig. 45.)
a. Jumper R to W/W1 and W2 thermostat connections on
furnace control. This keeps furnace locked in high--
heat operation.
b. Remove regulator adjustment cap from high--heat gas
valve pressure regulator (See Fig. 45) and turn high
heat adjusting screw (3/16--in. or smaller flat--tipped
screwdriver) counterclockwise (out) to decrease input
rate or clockwise (in) to increase input rate.
NOTE: DO NOT set high--heat manifold pressure less than
3.2-- In. W.C. or more than 3.8 In. W.C. for natural gas. If
manifold pressure is outside this range, change main burner
orifices to obtain manifold pressure in this range.
c. When correct input is obtained, replace caps that con-
ceal gas valve regulator adjustment screws. Main
burner flame should be clear blue, almost transparent .
d. Remove jumpers R to W/W1 and R to W2.
5. Verify natural gas input rate by clocking meter.
NOTE: Gas valve regulator adjustment caps must be in place for
proper input to be clocked.
a. Turn off all other gas appliances and pilots served by
the meter.
b. Move setup switch SW1-- 2 to ON position. This
keeps furnace locked in low--heat operation.
c. Jumper R to W/W1.
d. Run furnace for 3 minutes in low-- heat operation.
e. Measure time (in sec) for gas meter to complete 1
revolution and note reading. The 2 or 5 cubic feet dial
provides a more accurate measurement of gas flow.
f. Refer to Table 13 for cubic ft. of gas per hr.
g. Multiply gas rate cu ft./hr by heating value (Btuh/cu
ft.) to obtain input. If clocked rate does not match re-
quired input from Step 1, increase manifold pressure to
increase input or decrease manifold pressure to de-
crease input. Repeat steps d through g until correct
low-- heat input is achieved. Re--install low heat regu-
lator seal cap on gas valve.
h. Move setup switch SW1--2 to OFF position and jump-
er R to W/W1, and W2. This keeps furnace locked in
high-- heat operation. Repeat items d through g for
high-- heat operation.
6. Set Temperature Rise
NOTE: Blower access door must be installed when taking
temperature rise reading. Leaving blower access door off will
result in incorrect temperature measurements.
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in shorten furnace
life.
Set air temperature rise within limits specified on the rating
plate to prevent reduced life of furnace components.
Operation is within a few degrees of the mid --point of rise
rangewhensetupswitchSW1--4isOFF.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in overheating the
heat exchangers or condensing flue gases in heat exchanger
areas not designed for condensate.
Temperature rise must be within limits specified on unit
rating plate. Operation is within a few degrees of midpoint
ofriserangewhensetupswitchSW1--4isOFF.
CAUTION
!
When setup switch SW1--4 is ON, operation will be near the high
end of the rise range for improved comfort.
Furnace must operate within ranges of temperature rise specified
on the furnace rating plate. Determine air temperature rise as
follows:
a. Place thermometers in return and supply ducts as near
furnace as possible. Be sure thermometers do not see
heat exchanger so that radiant heat does not affect
readings. This practice is particularly important with
straight-- run ducts.
b. When thermometer readings stabilize, subtract return--
air temperature from supply-- air temperature to determ-
ine air temperature rise.
NOTE: Temperature rise can be determined for low--heat
operation by placing setup switch SW1 --2 on furnace control in
ON position and jumping R to W/W1. For high--heat operation,
place setup switch SW1--2 in OFF position and jumper R to W1
and R--W2 on furnace control. DO NOT forget to return setup
switch to OFF position and remove jumper upon completion of
testing.
c. This furnace is capable of automatically providing
proper airflow to maintain the temperature rise within
the range specified on furnace rating plate. If temperat-
ure rise is outside this range, proceed as follows:
(1.) Check gas input for low-- and high --heat opera-
tion.
(2.) Check derate for altitude if applicable.
(3.) Check all return and supply ducts for excessive
restrictions causing static pressure greater than
0.5-- In. W.C..
(4.) Ensure setup switch SW1--4 (Comfort/Efficiency)
is in OFF=Efficiency position when a bypass
humidifier is used. (See Fig. 26 for switch
location.)
(5.) Make sure proper model plug is installed.
d. Remove thermostat jumpers and release blower access
door switch.
e. Repeat Steps a through c as required to adjust for high
heat temperature rise.
f. When correct high heat input rate and temperature rise
is achieved, turn gas valve ON/OFF switch to OFF.
g. Release blower access door switch.
h. Remove manometer or similar device from gas valve.
i. Re--install manifold pressure tap plug in gas valve.
(See Fig. 45.)