GC9C96 Service Manual
SCHEDULED MAINTENANCE
19
Periodically during the heating season make a visual check of
the burner ames. Turn the furnace on at the thermostat. Wait
a few minutes since any dislodged dust will alter the normal
ame appearance. Flames should be stable, quiet, soft and
blue with slightly orange tips. They should not be yellow. They
should extend directly outward from the burner ports without
curling downward, oating or lifting o the ports.
Check the
Burner Flames for:
1. Stable, soft and blue.
2. Not curling, floating
or lifting off.
Before attempting to diagnose an operating fault code, run
a Heating Performance Test to determine if the heating
system is performing within 5% of the BTU input found on
the rating plate of the unit being tested. To conduct a heating
performance test, the BTU input to the unit must be calculated
(see Clocking a Gas Meter). Before clocking a gas meter,
contact your local utility to provide the caloric value (BTU
content) of the natural gas in the area.
It is also important to conrm the airow (CFM) is within the
temperature rise range (see Airow Data in spec sheet) and
external static pressure range (approximately 0.5” water
column). How-to instructions can be found in the service
manual under Checking External Static Pressure and
Checking Temperature Rise.
1. Turn o all gas appliances in the home.
2. Turn on the furnace. Ensure the furnace is operating at
a 100% ring rate on 2 stage and modulating furnace
product.
3. Once heating cycle is at a steady state (typically 15
minutes of operation), use a stopwatch to time how
long it takes the smallest unit of measure dial on the
gas meter to make a full revolution. In Table 1, one
cubic foot is selected. The smallest unit of measure will
vary depending on the gas meter.