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DGX Industrial Space Heating
Typical Control Center Layout
Dirty Filter Switch
Reference
7 15
14
12
13
4
1 6
2
3
5 8
9
10
11
1. Supply Motor Starter — 24 volt magnetic contacts
for starting supply motor.
2. Supply Overload — provides electronic overload
protection to supply motor.
3. Low Voltage Transformer — provides low voltage to
fan/heat enable controls.
4. Control Terminal Block — provides wiring access to
controls.
5. Fan Relay — allows power to pass to energize
motor starter.
6. Auxiliary Contact (optional) — provides one
normally closed and one normally open contact for
other equipment.
7. Dirty Filter Switch (optional) — monitors filter
pressure drop, turns on indicating light when
pressure drop is above field adjustable set point.
8. Heat Relay — allows power to pass to heating
controls.
9. Heating Terminal Block — provides wiring access to
heating controls.
10. Flame Safeguard — monitors flame, shuts down
unit when unsafe conditions are detected.
11. High Limit — prevents unit from discharging air
above a set point.
12. Low Voltage Transformer — reduces voltage to
Maxitrol system.
13. Amplifier — controls modulating valve, assures the
desired temperature is delivered.
14. Spark Generator — provides spark to ignite the
burner.
15. Transformer — provides voltage to Flame
Safeguard.
Common
Normally Open
Normally Closed
CCW to decrease trip point
CW to increase trip point
Negative Pressure
after the filters
Positive Pressure
before the filters
®