Check Heating Control; Check Gas Input; Adjust Gas Input - Bryant 677E A Series Installation Instructions Manual

Fig. 12 - - Monoport Burner
Check Gas Heating Control
Start and check the unit for proper heating control operation as
follows (see furnace lighting instructions located on the inside of
the control access panel):
1. Place room thermostat SYSTEM switch in the GAS HEAT
position and the fan switch in AUTO position.
2. Set the heating temperature control setting several degrees
higher than the room temperature reading.
3. The induced- -draft motor will always start on high speed for
the ignition sequence, regardless of the heating stage called.
4. After a pre- -purge time of 15 sec with the induced- -draft mo-
tor on high speed, the sparker will be energized for 3- -to- -8
sec, and the gas valve will be energized on low stage. If the
burners do not light, there is a 20- -sec delay before another
ignition attempt. If the burners still do not light by the 4
consecutive ignition attempt, there is a lockout. To reset the
lockout, break the 24- -v power to W1 and W2.
5. Once flame is established the integrated gas unit controller
(IGC) will look for 24- -v power to W1 and W2. If there is
24- -v power to W1 only, the IGC will switch the induced- -
draft motor down to low speed and maintain low stage on
the gas valve. If there is 24- -v power to both W1 and W2,
the IGC will maintain the induced- -draft motor on high
speed and switch the gas valve to high stage.
6. With the desired temperature set several degrees higher than
the room temperature, most thermostats will energize low
and high stage. Verify that the gas valve is energized on
high stage and the induced- -draft motor is on high speed.
7. Verify proper operation of low stage (induced- -draft motor
on low speed and gas valve on high stage) by turning the
heating temperature control setting down until the desired
temperature is 1 degree above room temperature. Most ther-
mostats will energize low stage only with a 1 degree differ-
ential.
8. The evaporator fan will turn on 30 sec after the flame has
been established. If there is 24- -v power to W1 only, the fan
will run on low heat speed. If there is 24- -v power to W1
and W2, the fan will run on high heat speed. Once the heat-
ing coll is satisfied, the IGC will turn the fan off after a
field- -selectable fan delay of 90, 120, 150, or 180 sec is
completed.

Check Gas Input

Check gas input and manifold pressure after unit start- -up (See
Table 5). If adjustment is required proceed as follows:
S The rated gas inputs shown in Table 5 is for altitudes from sea
level to 2000 ft (610 m) above sea level. These inputs are based
on natural gas with a heating value of 1025 Btu/ft
specific gravity, or propane gas with a heating value of 2500
3
Btu/ft at 1.5 specific gravity.
BURNER FLAME
BURNER
MANIFOLD
C99021
th
3
at 0.60
IN THE U.S.A.:
The input rating for altitudes above 2,000 ft (610 m) must be
reduced by 4% for each 1,000 ft (305 m) above see level.
For installations below 2,000 ft (610 m), refer to the unit rating
plate.
For installations above 2,000 ft (610 m). multiply the input on the
rating plate by the derate multiplier in Table 3 for correct input rate.
If the natural gs is not de- -rated by the utility company refer to
Table 4 for correct orifice sizes and manifold pressures.
Table 3 – Altitude Derate Multiplier for U.S.A.*
ALTITUDE FT (M) PERCENT OF DERATE
0--- 2000
0
(0--- 610)
2001--- 3000*
8--- 12
(610--- 914)
3001--- 4000
12--- 16
(915--- 1219)
4001--- 5000
16--- 20
(1220--- 1524)
5001--- 6000
20--- 24
(1524 --- 1829)
6001--- 7000
24--- 28
(1829--- 2134)
7001--- 8000
28--- 32
(2134--- 2438)
8001--- 9000
32--- 36
(2439--- 2743)
9001--- 10,000
36--- 40
(2744--- 3048)
*In Canada see Canadian Altitude Adjustment.
{Derate multiplier factors are based on midpoint altitude for altitude range.
IN CANADA:
The input rating for altitudes from 2,000 (610 m) to 4,500 ft (1372
m) above sea level must be derated 10% by an authorized Gas
Conversion Station or Dealer.
EXAMPLE:
90,000 Btu/hr Input Furnace Installed at 4300 ft.
Furnace Input Rate at X Derate Multiplier
Sea Level Factor
90,000 X
When the gas supply being used has a different heating value or
specific gravity, refer to national and local codes, or contact your
distributor to determine the required orifice size.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in reduced unit
and/or component life.
Do Not redrill an orifice. Improper drilling (burrs,
out- -of- -round holes, etc.) can cause excessive burner noise
and misdirection of burner flame. If orifice hole appears
damaged or it is suspected to have been redrilled, check
orifice hole with a numbered drill bit of correct size.

Adjust Gas Input

The gas input to the unit is determined by measuring the gas flow
at the meter or by measuring the manifold pressure. Measuring the
gas flow at the meter is recommended for natural gas units. The
manifold pressure must be measured to determine the input of
propane gas units.
Measure Gas Flow (Natural Gas Units)
Minor adjustment to the gas flow can be made by changing the
manifold pressure(s). The manifold pressure(s) must be maintained
between 3.2 and 3.8 IN. W.C. for high stage and between 1.4 and
2.0 IN. W.C. for low stage (208/230 VAC models). For 460 VAC
models, manifold pressure must be maintained between 3.2 and 3.8
IN. W.C.
15
DERATE MULTIPLIER
FACTOR{
1.00
0.90
0.86
0.82
0.78
0.74
0.70
0.66
0.62
= Furnace Input Rate at
Installation Altitude
0.90 = 81,000