Control Center Layout - Greenheck VSU Installation, Operation And Maintenance Manual

Reference

Control Center Layout

13
14
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/cooling enable controls.
4. Control Terminal Block — provides wiring
access to controls.
5. Fan Relay — allows power to pass to energize
motor starter.
6. High Voltage Enclosure — provides protection
from high voltage circuits.
7. Auxiliary Contact (optional) — provides one
normally closed and one normally open contact for
other equipment.
8. Exhaust Motor Starter (optional) — 24 volt
magnetic contacts for starting exhaust motor.
9. Exhaust Overload (optional) — provides
electronic overload protection to exhaust motor.
10. Transformer Fuse (optional) — provides proper
fusing for cooling transformer.
11. Terminal Block — provides wiring access to high
voltage circuits.
12. Exhaust Fuses (optional) — provides proper
fusing for exhaust fan motor(s).
13. Dirty Filter Switch (optional) — monitors filter
pressure drop, turns on indicating light when
pressure drop is above field adjustable set point.
14. Inlet Air Sensor (optional) — outdoor air stat
that automatically controls the heating and/or
cooling based on outdoor air temperature.
15. Remote Temperature Selector (optional) —
allows for remote temperature set point.
16. Heat Relay — allows power to pass to heating
controls.
17. Heating Terminal Block — provides wiring
access to heating controls.
®
22
19 20
18
21
17
10
24 25
11
27
26 28
4
15
18. Flame Safeguard/Spark Generator (Direct
Spark) — monitors flame, shuts down unit when
unsafe conditions are detected.
19. High Limit — prevents unit from discharging air
above a set point.
20. Low Voltage Transformer — reduces voltage to
Maxitrol system.
21. Amplifier — controls modulating valve, assures
the desired temperature is delivered.
22. Transformer (optional) — provides voltage to
optional evaporative cooling pump.
23. Cooling Relay (optional) — allows power to
pass to cooling controls.
24. Cooling Terminal Block (optional) — provides
wiring access to cooling controls.
25. Low Voltage Transformer (optional) — reduces
voltage to cooling controls.
26. Reset Timer (optional) — resets cooling system
to run a time interval.
27. Auto Drain Relay (optional) — assures supply
pump does not operate during drain interval.
Allows pump to operate in cooling mode.
28. Cooling Timer (optional) — allows for automatic
draining of the evaporative cooling system based
on time schedule.
Dirty Filter Switch
Negative Pressure
after the filters
Positive Pressure
before the filters
6
12
3
1 7 8
2 9
Common
Normally Open
Normally Closed
CCW to Decrease Trip Point
CW to Increase Trip Point
Model VSU Make-Up Air 35