Heat Wagon 1800, Installation And Maintenance Manual

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MODEL 1800 & 1800 SL
SEQUENCE OF COMPONENT OPERATION
1) POWER SUPPLY
Plug the heater into a 120 Volt grounded receptacle. Power is now at the 20 amp fuse and the 3
amp circuit breaker.
2) 20 AMP FUSE & 3 AMP BREAKER
If the circuit breaker and fuse are good there will be power at the thermostat and at the motor
relay (normally open).
3) THERMOSTAT
When the thermostat calls for heat there will be power at the fan switch.
4) FAN SWITCH
With the fan switch ON it sends power to the burner switch and the control relay.
5) BURNER SWITCH
This sends power to the airflow switch.
6) CONTROL RELAY
After receiving power from the fan switch it closes, sending power to the fan delay timer.
7) FAN DELAY TIMER
Receives power from the control relay and closes. Energizes the motor relays holding coil.
8) MOTOR RELAY
With its coil energized it closes its contacts, sending power to the fan motor.
9) FAN MOTOR
Turns the fan blade causing the air flow switch to close.
10) AIR FLOW SWITCH
Received its power from the burner switch and sends the power to the indicator light and the
flame safeguard control.
11) FLAME SAFEGUARD CONTROL
This sends power to transformer and the igniter and sends power out to the high temperature
limit switch.
12) HI TEMPERATURE LIMIT SWITCH
This switch has normally closed contacts, it sends power to the gas solenoid valve.
13) GAS SOLENOID VALVE
With its coil energized, the valve opens, gas passes through to the burner and ignites.
14) FLAME SAFEGUARD CONTROL
This is now sensing flame through the flame rod and the spark stops. The heater is operating.
15) THERMOSTAT
When it is satisfied, the contacts open taking power away from the ignition control, the gas
valve closes, and the fan delay timer is activated.
16) FAN DELAY TIMER
This will operate the fan motor for approximately 10 seconds and turns the fan off.
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