Intertek ACVC96 Service Instructions Manual page 77

MAINTENANCE
CONDENSATE DRAINAGE SYSTEM (QUALIFIED
SERVICER ONLY)
The drain tubes, trap, and field supplied drain line must be
checked annually and cleaned as often as necessary to
ensure proper condensate drainage.
FLAME SENSOR (QUALIFIED SERVICER ONLY)
Under some conditions, the fuel or air supply can create a
nearly invisible coating on the flame sensor. This coating
acts as an insulator, causing a drop in the flame sensing
signal. If this occurs, a qualified servicer must carefully clean
the flame sensor with steel wool. After cleaning, the flame
sensor output should be as listed on the specification sheet.
BURNERS
HIGH VOLTAGE
E
LECTRICAL COMPONENTS ARE CONTAINED IN BOTH
T
COMPARTMENTS. O AVOID ELECTRICAL SHOCK, INJURY OR
DEATH, DO NOT REMOVE ANY INTERNAL COMPARTMENT COVERS
OR ATTEMPT ANY ADJUSTMENT.
SERVICE AGENT AT ONCE IF AN ABNORMAL FLAME
APPEARANCE SHOULD DEVELOP.
Periodically during the heating season make a visual check
of the burner flames. Turn the furnace on at the thermostat.
Wait a few minutes since any dislodged dust will alter the
normal flame 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, floating or lifting off the ports.
Burner Flame
Proper equipment promotes faster, more efficient service and
accurate repairs resulting in fewer call backs.
HEATING PERFORMANCE TEST
Before attempting to diagnose an operating fault, run a heat-
ing performance test and apply the results to the Service
Problem Analysis Guide.
WARNING
C
ONTACT A QUALIFIED
Check the
Burner Flames for:
1. Stable, soft and blue.
2. Not curling, floating
or lifting off.
To conduct a heating performance test, the BTU input to the
furnace must be calculated.
After the heating cycle has been in operation for at least
fifteen minutes and with all other gas appliances turned off,
the gas meter should be clocked.
To find the BTU input, multiply the number of cubic feet of
gas consumed per hour by the heating value of the gas be-
ing used. (The calorific value of the gas being used is found
by contacting your local utility.)
EXAMPLE: It is found by the gas meter, that it takes forty
(40) seconds for the hand on the cubic foot dial to make one
complete revolution, with all appliances off, except the fur-
nace. Take this information and locate it on the gas rate
chart. Observe the forty (40) seconds, locate and read across
to the one (1) cubic foot dial column. There we find the num-
ber 90, which shows that ninety (90) cubic feet of gas will be
consumed in one (1) hour.
Let's assume the local gas utility has stated that the calo-
rific value of the gas is 1,025 BTU per cubic foot.
Multiplying the ninety (90) cubic feet by 1,025 BTU per cu-
bic foot gives us an input of 92,250 BTUH.
Checking the BTU input on the rating plate of the furnace
being tested.
EXAMPLE:
INPUT: 92,000 BTU/HR
OUTPUT CAP: 84,000
A
LWAYS CONNECT A MONOMETER TO THE OUTLET TAP AT THE GAS
VALVE BEFORE ADJUSTING THE PRESSURE REGULATOR.
SHOULD THE FINAL MANIFOLD PRESSURE VARY MORE THAN PLUS OR
MINUS .3 INCHES WATER COLUMN FROM 3.5 INCHES WATER COLUMN
FOR NATURAL GAS OR 10 INCHES WATER COLUMN FOR PROPANE GAS.
To adjust the pressure regulator on the gas valve, turn down
(clockwise) to increase pressure and input, and out (coun-
terclockwise) to decrease pressure and input.
The dissipation of the heat transferred to the heat exchanger
is now controlled by the amount of air circulated over its
surface.
The amount (CFM) of air circulated is governed by the exter-
nal static pressure in inches of water column of duct work,
cooling coil, registers, etc., applied externally to the unit
versus the motor speed tap (direct drive) or pulley adjust-
ments of the motor and blower (belt drive).
A properly operating unit must have the BTU per hour input
and CFM of air, within the limits shown to prevent short cy-
cling of the equipment. As the external static pressure goes
up, the temperature rise will also increase. Consult the proper
tables for temperature rise limitation.
CAUTION
I
N NO CASE
77