Greenheck Fan 470656 Check Operation - Recirculating Units optional, Recirculation Operation

Check Operation - Recirculating Units (optional)

NOTE

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

Recirculation Operation

The recirculation operation option is recommended when the ventilation equipment provides the primary source of heating for the space. Recirculation can

Building Pressure Control - a

modulating spring return actuator is used to control the return air amounts. The return air damper modulates from fully open to fully closed based on a signal from a remote pressure sensing device.

Turn both knobs to the upper most pressure setting. You may have to remove the outdoor pressure tap tubing. The return air damper should close.

BLOWER

EXHAUST

(OPTIONAL)

SUPPLY

		MAIN VALVES
HEAT
		DIRTY FILTERS
75	70
80	65	(OPTIONAL)
85	60
90	55

PHOTOHELIC

Building

Pressure Control

vary from 100% return air to 100% outside air. Control strategies include 2-position and modulating dampers.

Before the unit is left in service, the recirculation control system should be tested.

Set both knobs at the lowest setting and the damper should open. It may take one to two minutes for the damper to reach the desired position.

Reset the correct pressure limits before starting the unit.

2-Position Damper

A 2-position spring return actuator is used to control the return air amounts. The damper moves from open

to closed. If power is cut to the unit,	EXHAUST		BLOWER
the outdoor air damper will fail to		(OPTIONAL)
	SUPPLY
close.	HEAT		MAIN VALVES
Turn the recirculating switch on	RECIRCULATION
the remote control panel to each			DIRTY FILTERS
position and confirm that the return
	80 75 70	65	(OPTIONAL)
air damper adjusts accordingly. The	85	60
	90	55

damper actuator may take a few	2-Position
minutes to open or close.
	Damper Control

This picture shows a typical photohelic setting. Typical settings are 0.0 in. wg for the lower and 0.10 in. wg for the upper pressure setting. The needle in this photo 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

Modulating

Potentiometer Control - a modulating spring return actuator is used to control the return air amounts. The return air damper modulates from fully open to fully closed based on a signal from a remote potentiometer.

External Signal - a modulating spring return actuator is used to control the return air amounts. Return air damper modulates from fully open to fully closed based on an external 2-10 VDC or 4-20 mA signal (by others).

The return air damper will close with a 10 VDC or

20 mA signal. The return air damper should open with

To test potentiometer operation, turn the potentiometer to the two extremes. Confirm that the return air damper fully opens and fully closes. When the potentiometer is at 0, the return air damper will open. When the potentiometer is at 100, the return air damper will close. The damper actuator may take a few minutes to open or close.

BLOWERS

EXHAUST

(OPTIONAL)

SUPPLY

MAIN VALVES

HEAT

DIRTY FILTERS

(OPTIONAL)

Potentiometer

Control

a 2 VDC or 4mA signal. The damper actuator may take a few minutes to open or close.

®

Model IG / IGX Make-Up Air 37