Greenheck Fan 470658 MSX manual Building Pressure Control a

®

85

55

90

GREENHECK

Potentiometer

Control

60

BLOWER

MAIN VALVES

DIRTY FILTERS

(OPTIONAL)

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.

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.

GREENHECK

®

2-Position

Damper Control

(OPTIONAL)

DIRTY FILTERS

Turn the recirculating switch on the remote control panel to each position and confirm that the return air damper adjusts accordingly. The damper actuator may take a few minutes to open or close.

MAIN VALVES

BLOWER

75 70

RECIRCULATION

HEAT

SUPPLY

EXHAUST (OPTIONAL)

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, the outdoor air damper will fail to close.

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 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.

2-Position Damper

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

GREENHECK

With Maxitrol 44 Room Thermostat

Building

Pressure Control

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.

80

85

65

60

This picture shows a typical photohelic setting. Typical settings are 0.0 inch wc for the lower and 0.10 inch wc 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

90

55

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

EXHAUST

(OPTIONAL)

SUPPLY

HEAT

75 70

80

65

Model MSX Make-Up Air 23