White Rodgers NP110 Install Manual page 23

Symptom
No Heat
Possible Cause
1. Pilot light not lit.
2. SYSTEM Switch not set to HEAT.
3. Loose connection to thermostat
or system.
4. Furnace Lock-Out Condition.
Heat may also be intermittent.
5. Heating system requires
service or thermostat requires
replacement..
Corrective Action
Re-light pilot.
Set SYSTEM Switch to HEAT and raise setpoint temperature
above room temperature.
Verify thermostat and system wires are securely attached.
Many furnaces have safety devices that shutdown when a
lock-out condition occurs. If the heat works intermittently
contact the furnace manufacturer or local service person for
assistance.
Diagnostic: Set SYSTEM Switch to HEAT and raise the
setpoint above room temperature. Within a few seconds
the thermostat should make a soft click sound. This sound
usually indicates the thermostat is operating properly. If the
thermostat does not click, try the reset operation listed below.
If the thermostat does not click after being reset contact your
heating and cooling service person or place of purchase for
a replacement. If the thermostat clicks, contact the furnace
manufacturer or a service person to verify the heating is
operating correctly.
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