BLOWERS
EXHAUST
(OPTIONAL)
SUPPLY
MAIN VALVES
HEAT
DIRTY FILTERS
(OPTIONAL)
Potentiometer
Control

Check Operation - VAV Units (optional)

NOTE

Blower Start-Up, Steps 1-5 should be performed before the blower is run.

NOTE

For maintenance issues associated with variable frequency drives, consult the drive’s manual supplied with the unit. The drives are programmed at the factory and should not need any adjustment during installation and start-up. For kitchen applications, the drive may be located in the kitchen

Building Pressure Control —

a variable frequency drive is controlled according to input from a pressure sensing device.

Turn both knobs to the upper most pressure setting. You may have to remove the outdoor pressure tap tubing. VAV systems should go to maximum speed. Set both knobs at the lowest setting and the VAV systems should go to minimum speed.

Reset the correct pressure limits before starting the unit.

BLOWER

EXHAUST

(OPTIONAL)

SUPPLY

 

 

MAIN VALVES

HEAT

 

 

 

DIRTY FILTERS

75

70

 

80

65

(OPTIONAL)

85

60

 

 

90

55

 

PHOTOHELIC

Building

Pressure Control

or in the unit.

Variable Volume Operation

The variable volume option is recommended when a building’s exhaust volume may vary. This option enables the make-up air volume to track with the exhaust volume, providing only the amount of make- up air required. Control strategies include 2-speed VFD motors and modulating blowers. Before the unit is left in service, the variable volume control system should be tested.

This picture depicts a typical photohelic setting. Typical settings are 0.0 in. wg for the lower pressure setting and 0.10 in. wg for the upper pressure setting. The needle indicates a negative building pressure. During correct operation, the indicating needle will remain between or near the setting needles.

Pressure Indicating

Pressure Setting

Needle

Needles

Pressure Setting Knobs

Photohelic Gauge

2-Speed VFD Motor

A variable frequency drive (VFD) is used on a single speed motor to control air volumes. The VFD is factory-programmed for 2 speed operations. It can be switched to low or high speed from a remote control panel. Turn the fan speed switch on the remote control panel to each position and confirm that the fan speed adjusts accordingly.

External Signal — a variable

frequency drive is controlled according to input from an external 2-10 VDC or 4-20 mA signal (by others).

A 2 VDC or 4 mA signal will send the blower to low speed. The blower will go to maximum speed with a 10 VDC or 20 mA signal.

Variable Kitchen Control — A variable frequency drive is controlled by input from a remote speed control. This unit allows automatic adjustment of make-up air volumes based on varying cooking loads.

Modulating

Potentiometer Control — a variable frequency drive is controlled by input from a remote

speed selector (potentiometer). This

unit allows easy manual adjustment of make-up air volumes. To test

potentiometer operation, turn the

potentiometer to the two extremes. With variable volume, make sure the

fan goes to maximum and minimum speed.

When the potentiometer is at 0, the fan speed will be at its minimum. When the potentiometer is at 100, the fan will be at its maximum speed.

36 Model IG / IGX Make-Up Air

®

Page 36
Image 36
Greenheck Fan 470656 manual Check Operation VAV Units optional, Building Pressure Control, External Signal a variable