Bryant 352AAV Installation, Start-Up, And Operating Instructions Manual page 58

ON/OFF
SWITCH
INLET
PRESSURE
TAP
MANIFOLD
PRESSURE
TAP
Fig. 58 - - Redundant Automatic Gas Control Valve
BURNER FLAME
MANIFOLD
Fig. 59 - - Burner Flame
Fig. 60 - - Burner Orifice
3. Verify Natural Gas Input Rate By Clocking Gas Meter.
NOTE: Be sure all pressure tubing, combustion-air and vent
LOW-FIRE
pipes, and burner enclosure front are in place when checking
ADJUSTMENT
ALLEN SCREW
input by clocking gas meter.
(UNDER CAP)
HIGH-FIRE
ADJUSTMENT
ALLEN SCREW
(UNDER CAP)
EXAMPLE:
Furnace Input Rate
NOTE: Clocking gas input rate MUST always be performed
A97358
with the burner box cover INSTALLED.
BURNER
NOTE: Be sure heating value of gas used for calculations is
correct for your altitude. Consult local gas utility for altitude
adjustment of gas heating value.
A89020
Example:
(0 - - 2000 ft altitude)
Furnace input from rating plate is 100,000 Btuh.
Btu heating input = Btu/cu ft X cu ft/hr
Heating value of gas = 975 Btu/cu ft
Time for 1 revolution of 2-cu ft dial = 70 sec
Gas rate = 103 cu ft/hr (from Table 17)
Btu heating input = 103 X 975 = 100,425 Btuh. In this
example, the orifice size and manifold pressure adjustment
BURNER
ORIFICE
is within ±2 percent of the furnace input rate.
NOTE: Measured gas inputs (high-heat and low-heat) must be
within ±2 percent of that stated on furnace rating plate when
A93059 installed at sea level or derated per that stated above when
installed at higher altitudes.
58
a. Calculate high-altitude adjustment (if required).
UNITED STATES
At altitudes above 2000 ft, this furnace has been
approved for 2 percent derate for each 1000 ft above
sea level. See Example and Table 16 for derate
multiplier factor.
100,000 Btuh input furnace installed at 4300 ft.
X Derate
at Sea Level Multiplier
Factor
100,000 X 0.91
CANADA
At installation altitudes from 2001 to 4500 ft, this
furnace must be derated 5 percent by an authorized Gas
Conversion Station or Dealer. To determine correct
input rate for altitude, see example above and use 0.95
as derate multiplier factor.
b. Reinstall burner box cover.
c. Check that gas valve adjustment caps are in place for
proper input to be clocked.
d. Obtain yearly heat value average for local gas supply.
e. Check and verify orifice size in furnace. NEVER
ASSUME THE ORIFICE SIZE. ALWAYS CHECK
AND VERIFY.
f. Turn off all other gas appliances and pilots.
g. Move setup switch SW-1 to ON position. This keeps
furnace locked in low-heat operation.
h. Jumper R-to-W/W1.
i. Let furnace run for 3 minutes in low-heat operation.
j. Measure time (in sec) for gas meter to complete 1
revolution. Note reading.
k. Refer to Table 17 for cubic ft of gas per hr.
l. Multiply gas rate cu ft/hr by heating value (Btu/cu ft).
m. Move setup switch SW-1 to OFF position and jumper
R and W1 and W2 thermostat connections. This keeps
furnace locked in high-heat operation. Repeat items 'i'
through 'l' for high-heat operation.
n. Remove jumper across R, W/W1, and W2 thermostat
connections to terminate call for heat.
= Furnace Input Rate
at Installation
Altitude
= 91,000