Reznor UEAS Unit Installation Manual - Manual (Page 30)

9.3.2 Limit Control
All units are equipped with a temperature activated auto reset limit control. The
control is factory set and is non-adjustable. If the setpoint is reached, the limit con-
trol will interrupt the electric supply to the gas valve. This safety device provides
protection in the case of motor failure or lack of airflow due to a restriction at the
inlet or outlet. (For location, see FIGURE 28, page 37.)
CAUTION: The auto reset limit control will continue to
shut down the heater until the cause is corrected. Never
bypass the limit control; hazardous conditions could
result. See Hazard Intensity Levels, page 2.
9.3.3 Vent Temperature
Limiting Switch
All Model UEAS heaters are equipped with a door switch which prevents the
heater from operating when the service door panel is open. The service panel has
a pliable gasket material that fully seals the door to provide added protection from
building air entering the combustion zone of the heater. (For switch location, see
FIGURE 28, page 37.)
9.3.4 Door Switch
9.3.5 Fan Motor
Overload Protection
The fan motor is equipped with thermal overload protection of the automatic reset
type. Should the motor refuse to run, it may be because of improper current char-
acteristics. Make certain that the correct voltage is available at the motor.
This heater is equipped with a direct spark integrated control module (circuit
board). The module monitors the safety devices and controls the operation of the
fan and venter motors and the gas valve between heat cycles.
10.0 Ignition System
Control Status - Green LED Codes
Steady ON ....... Normal Operation, No call for heat
Fast Flash ........ Normal Operation, Call for heat
1 Flash ............. System Lockout, Failed to detect or sustain
flame
2 Flashes ......... Pressure Switch Did Not Close within 30
Seconds of Venter motor
3 Flashes ......... High Limit or Vent Temperature Limit
Switch Open
4 Flashes ......... Pressure switch is closed before venter
motor is energized
Steady OFF ..... Blown Fuse, No Power, or Defective Board
Flame Status - Yellow LED Codes
Steady ON ....... Flame is sensed
Slow Flash ....... Weak flame (current below 1.0 microamps
±50%)
Fast Flash ........ Undesired Flame (valve open and no call
for heat)
FIGURE 25 – DSI Integrated Control
Module (circuit board)
LED lights are visible through a viewport.
1097-83-218
MODEL 1097-218
LED
Lights
9.0 Controls (cont’d)
9.3 Safety Controls
(cont’d)
This heater is equipped with a temperature activated, manually reset switch to
limit the temperature of the vent gases to below 145°F. The switch is attached to
the side of the combustion air venter housing. If the setpoint is reached, the switch
will interrupt the electric supply to the gas valve. If the vent temperature switch
is activated, identify and correct the cause before resetting the switch. Refer to
the Maintenance Section for information on probable causes and instructions on
resetting the switch.
DANGER
If the manual vent temperature switch activates, identify and correct the cause
before resetting the switch. Never bypass the vent temperature switch; hazardous
conditions could result. See Hazard Intensity Levels, page 2.
Form I-UEAS, Page 30