Bryant 311AAV Series 100 Installation, Start-Up, And Operating Instructions Manual page 24

INLET
PRESSURE
TAP
Fig. 31–Redundant Automatic Gas Control Valve
CAUTION: DO NOT bottom out gas valve regulator
adjusting screw. This can result in unregulated manifold
pressure and result in excess overfire and heat exchanger
failures.
NOTE: If orifice hole appears damaged or it is suspected to have
been redrilled, check orifice hole with a numbered drill bit of
correct size. Never redrill an orifice. A burr-free and squarely
aligned orifice hole is essential for proper flame characteristics.
BURNER FLAME
MANIFOLD
Fig. 32–Burner Flame
d. After correct manifold pressure is obtained, replace gas
valve regulator adjustment screw cap and verify adjusted
gas input rate using method outlined in item 4.
e. Burner flame should be clear blue, almost transparent.
(See Fig. 32.)
6. Verify natural gas input rate by clocking gas meter.
NOTE: Be sure pressure tubing and vent pipes are in place when
checking input by clocking gas meter.
a. Calculate high-altitude adjustment (if required).
UNITED STATES
At altitudes above 2000 ft, this furnace has been ap-
proved for a 4 percent derate for each 1000 ft above sea
level. See Table 10 for derate multiplier factor.
ON AND OFF
SWITCH
GAS PRESSURE
REGULATOR
ADJUSTMENT
MANIFOLD
PRESSURE TAP
A00157
BURNER
A89020
CAUTION: DO NOT redrill orifices. Improper drilling
(burrs, out-of-round holes, etc.) can cause excessive
burner noise and misdirection of burner flames. This can
result in flame impingement of heat exchangers, causing
failures.
TABLE 8–ALTITUDE DERATE MULTIPLIER FOR U.S.A.
ALTITUDE
(FT)
0–2000
2001–3000
3001–4000
4001–5000
5001–6000
6001–7000
7001–8000
8001–9000
9001–10,000
* Derate multiplier factor is based on midpoint altitude for altitude range.
EXAMPLE:
88,000 BTUH INPUT FURNACE INSTALLED AT 4300 FT.
Furnace Input Rate
at Sea Level
88,000
CANADA
At installation altitudes from 2000 to 4500 ft, this furnace must be
derated 10 percent by an authorized Gas Conversion Station or
Dealer. To determine correct input rate for altitude, see example
below and use 0.90 as derate multiplier factor.
b. Check that gas valve adjustment cap is in place for
proper input to be clocked.
c. Obtain yearly heat value average for local gas supply.
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.
—24—
BURNER
ORIFICE
Fig. 33–Orifice Hole
PERCENT DERATE MULTIPLIER
OF DERATE FACTOR FOR U.S.A.*
0 1.00
8–12 0.90
12–16 0.86
16–20 0.82
20–24 0.78
24–28 0.74
28–32 0.70
32–36 0.66
36–40 0.62
Derate Furnace Input Rate
X Multiplier = at Installation
Factor Altitude
X 0.82 = 72,160
A93059