
47
Reference
Control Center Layout
Reference
1.
Heating/Cooling Inlet Air Sensor (Optional) - Ductstat that automatically de-energizes burner when inlet air
temperature rises above set point, or shuts down cooling when temperature falls below set point.
2.
Flame Safeguard/Spark Generator - Monitors flame, shuts down unit when unsafe conditions are detected.
3.
High Limit - Prevents unit from discharging air above a set point.
4.
Building Freeze Protection (Optional) - Prevents unit from discharging air below a set point after a time
delay. Temperature and time delay are field adjustable.
5.
Filter Gauge (Optional) - Monitors filter pressure drop, turns on indicating light when pressure drop is
above field adjustable set point.
6.
Terminal Strip - 24 Volt power strip for control wiring.
7.
Main Disconnect - On/Off switch, provides single point power connection to unit.
8.
Grounding Lugs - Completes electrical circuit
9.
Motor Starters - 24 Volt magnetic contacts for starting motors, comes standard with electronic overload,
may be provided with auxiliary contacts.
10.
Amplifier - Controls modulating valve, assures the desired temperature is delivered.
11.
Low Voltage Transformer - Reduces voltage to the Maxitrol system.
12.
Control Transformer - Provides 24 Volts for controls and 120 Volts for valves.
13.
Secondary fuses - Provides proper fusing for all electrical components other than the motors.
14.
Motor Fuses - Provides proper fusing for supply and exhaust fan motor(s).
Figure 67.
Direct Spark Gas Control Center
1
2
10
3
4
6
11
13
14
9
7
8
12
5