Greenheck MSX (470658) - Manual (Page 37)

37 Modular Supply Make-Up Air Unit
®
Reference
Typical Control Center Layout
7
8
4
6
9 11
12
10
5
14
2
13
18
3 1
16
15 17
1. Primary Fuses — provides proper fusing to low
voltage transformer.
2. Low Voltage Transformer — provides low
voltage to controls and optional evaporative cooling
controls.
3. Low Voltage Fuse — provides proper fusing to
controls and optional evaporative cooling controls.
4. Control Terminal Block — provides wiring
access to controls.
5. Building Freeze Protection Timer (optional) —
prevents the discharge of cold air into the building.
6. Fan Relay — allows power to pass to energize
motor starter.
7. Supply Motor Starter — 24 volt magnetic
contacts for starting supply motor.
8. Supply Overload — provides electronic overload
protection to supply motor.
9. Auxiliary Contact (optional) — provides one
normally closed and one normally open contact for
other equipment.
10. Exhaust Fuses (optional) — provides proper
fusing for exhaust fan motor(s).
11. Exhaust Motor Starter (optional) — 24 volt
magnetic contacts for starting exhaust motor.
12. Exhaust Overload (optional) — provides
electronic overload protection to exhaust motor.
13. Inlet Air Sensor (optional) — outdoor air stat
that automatically controls the cooling based on
outdoor air temperature.
14. Cooling Relay (optional) — allows power to pass
to cooling controls.
15. Reset Timer (optional) — resets cooling system
to run a time interval.
16. Auto Drain Relay (optional) — assures supply
pump does not operate during drain interval. Allows
pump to operate in cooling mode.
17. Cooling Timer (optional) — allows for automatic
draining of the evaporative cooling system based
on time schedule.
18. Dirty Filter Switch (optional) — monitors filter
pressure drop, turns on indicating light when
pressure drop is above field adjustable set point.
Dirty Filter Switch
Negative Pressure
after the filters
Common
Normally Open
Normally Closed
CCW to Decrease Trip Point
CW to Increase Trip Point
Positive Pressure
before the filters