Weather-Rite UHA100 Installation, Operation & Service Manual - page 41
SECTION 12: U
SER
I
NSTRUCTIONS
33 of 51
Figure 19: Manual Reset Limit Switch
12.3 Lighting Instructions
12.3.1 To Turn On Heater
1. Ensure that the electrical and gas supplies to
the heater are on. Check that the on site
controls are "ON".
IMPORTANT: The thermostat setting must be above
the ambient temperature for the heater to operate.
2. The automatic firing sequence will begin as
described on Page 29, Figure 16. The heater
will now operate automatically under the control
of the on site controls.
12.3.2 To Turn Heater Off
Set the thermostat to the "OFF" position.
The burner will turn off immediately.
The fan will continue to run for 90 seconds.
To restart, turn the thermostat on or above room
temperature.
12.4 Simple Troubleshooting
Some possible reasons for the heater not operating
are:
1. Gas supply not "ON".
2. Electricity supply not "ON".
3. The time and/or temperature controls are not
"ON".
4. A limit switch may have operated. This may be
caused by an interruption of the electrical
supply, failure of the distribution fan or vent or
heat exchanger blockage.
If a temperature limit switch persistently trips, there
is a fault which must be investigated by a contractor
qualified in the installation and service of gas-fired
heating equipment.
12.4.1 Simple Troubleshooting (Burner Faults)
If the burner fails to ignite for any reason, it will retry
for ignition (four trials total). After four unsuccessful
ignition trials, the control will put the heater into
lockout for one hour.
Lockout should not occur during normal operation of
the heater and indicates there is a fault condition
which must be corrected. There is an LED light on
the ignition control that flashes codes to assist in
fault correction. See Page 33, Figure 20 for LED
indication codes.
Figure 20: LED Diagnostic Codes
Reset Button
To reset manual reset limit switch, press reset
button. NOTE: To reset, the switch must be cool.
Description
Part Number
Manual Reset Limit Switch
90412106
LED INDICATION FAULT MODE
Slow Flash
Normal Operation - No call for heat.
Fast Flash
Normal Operation - Call for heat.
2 Flashes
Ignition Lockout - No flame detected.
3 Flashes
Airflow Fault - Pressure switch open or closed.
4 Flashes
Temperature Limit or
Manual Reset Limit Switch Open
5 Flashes
Flame Sense Error - Gas valve not energized.
Steady On
Internal Control Failure