Rollout Limit; Pressure Switches; Flame Sensor; Troubleshooting - Amana MVM97 Installation Instructions Manual

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),
auto-reset sensors. These limits guard against overheat-
ing 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 prop-
erly 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/mani-
fold assembly which uses the principle of flame rectifica-
tion to determine the presence or absence of flame.

Troubleshooting

Electrostatic Discharge (ESD) Precautions

NOTE: Discharge body's static electricity before touch-
ing unit. An electrostatic discharge can adversely affect
electrical components.
Use the following precautions during furnace installation
and servicing to protect the integrated control module
from damage. By putting the furnace, the control, and
the person at the same electrostatic potential, these
steps will help avoid exposing the integrated control
module to electrostatic discharge. This procedure is
applicable to both installed and uninstalled (ungrounded)
furnaces.
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 elec-
trostatic 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 elec-
tricity; (i.e., do not move or shuffle your feet, do not
touch ungrounded objects, etc.). If you come in con-
tact 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 Codes for assistance in de-
termining the source of unit operational problems. The
dual 7-segment LED display will display an error code that
may contain a letter and number. The error code may be
used to assist in troubleshooting 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 a E 0 code displayed on the dual 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 nor-
mal 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 sec-
onds then reset to previous setting.
NOTE: If the condition which originally caused the lock-
out still exists, the control will return to lockout. Refer
to the Troubleshooting Codes for aid in determining the
cause.
WARNING
.