Goodman ACVC96 BA Series Service And Troubleshooting page 37

SYSTEM OPERATION
Primary Limit
The primary limit control is located on the partition panel and
monitors heat exchanger compartment temperatures. It is a
normally-closed (electrically), automatic reset, temperature-
activated sensor. The limit guards against overheating as
a result of insufficient conditioned air passing over the heat
exchanger.
Auxiliary Limit
The auxiliary limit controls are located on or near the circulator
blower and monitors blower compartment temperatures. They
are a normally-closed (electrically), manual-reset sensors.
These limits guard against overheating as a result of insufficient
conditioned air passing over the heat exchanger.
Rollout Limit
The rollout limit controls are mounted on the burner/manifold
assembly and monitor the burner flame. They are normally-closed
(electrically), manual-reset sensors. These limits guard against
burner flames not being properly drawn into the heat exchanger.
Pressure Switches
The pressure switches are normally-open (closed during
operation) negative air pressure-activated switches. They monitor
the airflow (combustion air and flue products) through the heat
exchanger via pressure taps located on the induced draft blower
and the coil front cover. These switches guard against insufficient
airflow (combustion air and flue products) through the heat
exchanger and/or blocked condensate drain conditions.
Flame Sensor
The flame sensor is a probe mounted to the burner/manifold
assembly which uses the principle of flame rectification to
determine the presence or absence of flame.
Check the burner flames for:
1. Stable, soft and blue
2. Not curling, floating, or lifting off.
Burner Flame
Troubleshooting
Electrostatic Discharge (ESD) Precautions
NOTE: Discharge body's static electricity before
touching unit. An electrostatic discharge can adverse-
ly affect electrical components.
Use the following precautions during furnace instal-
lation and servicing to protect the integrated control
module from damage. By putting the furnace, the con-
trol, and the person at the same electrostatic potential,
these steps will help avoid exposing the integrated
control module to electrostatic discharge. This pro-
cedure is applicable to both installed and uninstalled
(ungrounded) furnaces.
Figure 55
1. Disconnect all power to the furnace. Do not touch the
integrated control module or any wire connected to the
control prior to discharging your body's electrostatic charge
to ground.
2. Firmly touch a clean, unpainted, metal surface of the furnace
away from the control. Any tools held in a person's hand
during grounding will be discharged.
3. Service integrated control module or connecting wiring
following the discharge process in step 2. Use caution not to
recharge your body with static electricity; (i.e., do not move or
shuffle your feet, do not touch ungrounded objects, etc.). If
you come in contact with an ungrounded object, repeat step
2 before touching control or wires.
4. Discharge your body to ground before removing a new control
from its container. Follow steps 1 through 3 if installing the
control on a furnace. Return any old or new controls to their
containers before touching any ungrounded object.
Diagnostic Chart
HIGH VOLTAGE !
T
O AVOID PERSONAL INJURY OR DEATH DUE TO
,
ELECTRICAL SHOCK DISCONNECT ELECTRICAL POWER
BEFORE
PERFORMING ANY SERVICE OR MAINTENANCE
Refer to the Troubleshooting Chart in the back of this
manual for assistance in determining the source of unit
operational problems. The 7-segment LED displays
will display an error code that may contain a letter and
number. The error code may be used to assist in trou-
bleshooting the unit.
Resetting From Lockout
Furnace lockout results when a furnace is unable to
achieve ignition after three attempts during a single
call for heat. It is characterized by a non-functioning
furnace and an  code displayed on the 7-segment
display. If the furnace is in "lockout", it will (or can be)
reset in any of the following ways.
1. Automatic reset. The integrated control module will
automatically reset itself and attempt to resume normal
operations following a one hour lockout period.
2. Manual power interruption. Interrupt 115 volt power to
the furnace.
3. Manual thermostat cycle. Lower the thermostat so that
there is no longer a call for heat for 1 -20 seconds
WARNING
.
37