Auxiliary Limit; Burner Temperature Switch; Pressure Sensor; Flame Sensor - Intertek MES80 Installation Instructions Manual

Auxiliary Limit

The auxiliary limit control is located either on or near the
circulator blower and monitors heat exchanger compartment
temperatures. The control is a normally closed (electrically),
automatic reset, temperature activated sensor. It guards
against overheating resulting from insufficient air passing
over the heat exchanger. The auxiliary limit control is suitable
for both horizontal right and horizontal left installations.
Regardless of airflow direction, it does not need to be
relocated.

Burner Temperature Switch

The burner temperature switch is mounted on the burner
assembly to monitor the burner box temperature. It is normally
closed (electrically), auto-reset sensor. This switch guards
agianst the burner flames not being properly drawn into the
heat exchanger.

Pressure Sensor

The pressure sensor is mounted near induced draft blower.
Its function is to regulate the induced draft blower's speed in
order to maintain proper air-fuel ratio for clean and reliable
combustion. The pressure sensor also guards agianst
insufficient airflow (combustion air and flue products) through
the heat exchanger.

Flame Sensor

The flame sensor is a probe mounted near the burner
assembly which uses the principle of flame rectification to
determine the presence or absence of flame.

Troubleshooting

Diagnostic Chart

Refer to the troubleshooting chart in the Appendix for assistance
in determining the source of unit operational problems. The
red diagnostic LED blinks to assist in troubleshooting the unit.
The number of blinks refer to a specific code.
NOTE: To clear all alarm codes, depress the push button for
5 -10 seconds.

Fault Code Retrieval

The ignition control is equipped with a momentary push button
that can be used to display on the diagnostic LED the last five
faults detected by the control. The control must be in Standby
Mode (no thermostat inputs) to use the feature. Depress and
release the SW1 button for less than 5 seconds. The diagnostic
LED will then display the flash codes associated with the last
five detected faults. The order of display is the most recent
fault to the least recent fault.

Clear Fault Memory

The push button (SW1) on the ignition control can be used to
erase the fault code as well. The control must be in Standby
Mode (no thermostat inputs) to use the feature. Press and
hold SW1 button for more than 5 secs, but less than 10 secs
and the control will erase the stored fault code history. LED
will display rapid green flash to indicate the fault history has
been cleared.

Resetting From Lockout

Furnace lockout results when a furnace is unable to achieve
ignition after three attempts. It is characterized by a non-
functioning furnace and a fault code will be displayed . 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 120 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 then
reset to previous setting.
NOTE: If the condition which originally caused the lockout still
exists, the control will return to lockout. Refer to the Diagnostic
Chart for aid in determining the cause.
Maintenance
T
O AVOID ELECTRICAL SHOCK
ELECTRICAL POWER BEFORE PERFORMING ANY SERVICE OR
. O
MAINTENANCE NLY QUALIFIED SERVICER SHOULD SERVICE OR
PERFORM MAINTENANCE
Annual inspection
The furnace should be inspected by a qualified installer, or
service agency at least once per year. This check should be
performed at the beginning of the heating season. This will
ensure that all furnace components are in proper working
order and that the heating system functions appropriately. Pay
particular attention to the following items. Repair or service
as necessary.
• Flue pipe system: Check for blockage and/or leakage.
Check the outside termination and the connections
at and internal to the furnace.
• Heat exchanger: Check for corrosion and/or buildup
within the heat exchanger passageways.
• Burners: Check for proper ignition, and flame sense.
• Wiring: Check electrical connections for tightness
and/or corrosion. Check wires for damage.
• Filters: Check filters and determine if any need to be
replaced.
26
WARNING
, ,
INJURY OR DEATH DISCONNECT