Bryant 987MB Installation, Start-Up, Operating And Service And Maintenance Instructions page 53

987MB: Installation, Start-up, Operating and Service and Maintenance Instructions
4. Remove funnel; replace collector box drain plug.
5. Connect field-supplied 5/8-in. (16 mm) ID tube to middle collector
box drain port.
6. Pour one quart (liter) of water into funnel/tube. Water should run
through collector box, overfill condensate trap, and flow into open
field drain.
7. Remove funnel and tube from collector box and replace collector
box drain plug.
Purge Gas Lines
If not previously done, purge the lines after all connections have been
made and check for leaks.
WARNING
!
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death,
and/or property damage.
Never purge a gas line into a combustion chamber. Never test for gas
leaks with an open flame. Use a commercially available soap solution
made specifically for the detection of leaks to check all connections. A
fire or explosion may result causing property damage, personal injury
or loss of life.
Adjustments
CAUTION
!
FURNACE DAMAGE HAZARD
Failure to follow this caution could result in reduced furnace life.
DO NOT push or force gas valve adjusting screw. This can result in
damage to the adjustment screw resulting in incorrect manifold
pressure, which can result in a no heat situation or shorten the life of the
heat exchangers.
CAUTION
!
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in reduced furnace life.
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, see Fig. 62.
Fig. 62 – Orifice Hole
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
For proper operation and long term reliability, the Furnace input rate
must be within +/-2 percent of input rate on furnace rating plate or as
adjusted for altitude.
The gas input rate on rating plate is for installations at altitudes up to
2000 ft. (609.6M).
The NATURAL GAS manifold pressure adjustments in Tables 18 and
19 compensate for BOTH altitude AND gas heating value. DO NOT
apply an additional derate factor to the pressures show in
Table
are AS-MEASURED AT ALTITUDE.
The heating content of natural gas at altitude may already provide for a
reduction in capacity of the furnace. Be sure to obtain the expected
in-season gas heating value of the gas from the gas supplier BEFORE
making any adjustments for capacity or altitude. Refer to
Table
for certain gas heating values.
Refer to the instructions provided in the factory-specified LP/Propane
conversion kit for instructions for setting gas manifold pressures for
LP/Propane applications.
In the USA, the input rating for altitudes above 2000 ft. (609.6M) must
be reduced by 2 percent for each 1000 ft. (304.8M) above sea level.
Refer to
In Canada, the input rating must be reduced by 5 percent for altitudes of
2000 ft. (609.6M) to 4500 ft. (1371.6M) above sea level. The natural gas
manifold pressures in Tables 18 and 19 adjust for BOTH altitude and
natural gas heating value.
*Derate multiplier factors are based on midpoint altitude for altitude range.
NOTE: For Canadian altitudes of 2000 to 4500 ft. (610 to 1372 M), use
USA altitudes of 2001 to 2000 ft. (611 to 914 M) in
To adjust manifold pressure to obtain the proper input rate, first,
determine if the furnace has the correct orifice installed. At higher
altitudes or different gas heat contents, it may be necessary to change the
factory orifice to a different orifice. Tables have been provided in the
furnace installation instructions to match the required orifice to the
manifold pressure to the heat content and specific gravity of the gas.
THERE ARE TWO MANIFOLD PRESSURE TABLES
Use Table 18 for all models EXCEPT 987MB60060C21
Use Table 19 for all models 987MB60060C21 ONLY
BURNER
To do this:
ORIFICE
1. Obtain average yearly gas heat value (at installed altitude) from
2. Obtain average yearly specific gravity from local gas supplier.
A93059 3. Find installation altitude range for your installation in the manifold
53
NOTICE
!
20. The values in this table are NOT referenced to sea level; they
20. No adjustments to the furnace may be necessary at altitude
Table 16.
Table 16 – Altitude Derate Multiplier for U.S.A.*
ALTITUDE
FT. M
0–2000 0-610
2001–3000 610-914
3001–4000 914-1219
4001–5000 1219-1524
5001–6000 1524-1829
6001–7000 1829-2134
7001–8000 2134-2438
8001–9000 2438-2743
9001–10,000 2743-3048
NOTICE
!
local gas supplier.
pressure tables. See Table 13
Table 19
Table 19
PERCENT DERATE
OF MULTIPLIER
DERATE FACTOR*
0 1.00
4-6 0.95
6-8 0.93
8-10 0.91
10-12 0.89
12-14 0.87
14-16 0.85
16-18 0.83
18-20 0.81
Table 13.
for 20,000 BTUh Max-Heat/8,000
or
or