Greenheck HB-120 Installation Manual

Part number 469620

HB series

Installation, Operation, and Maintenance Instructions

This manual is the property of the owner, and is required for future maintenance. Please leave it with the
owner when the job is complete.

RECEIVING AND HANDLING

Upon receiving dampers, check for both obvious
and hidden damage. If damage is found, record all
necessary information on the bill of lading and file
a claim with the final carrier. Check to be sure that
all parts of the shipment, including accessories, are
accounted for.

Dampers must be kept dry and clean. Indoor
storage and protection from dirt, dust and the
weather is highly recommended. Do not store at
temperatures in excess of 100°F(37ºC).

Due to continuing research, Greenheck reserves the right to change specifications without notice.

Improper installation, adjustment, alteration,
service or maintenance can cause property
damage, injury or death. Read the installation,
operating, and maintenance instructions
thoroughly before installing or servicing this
equipment.

SAFETY WARNING:

Instructions

The following instructions should be followed when trying to adjust counterbalance weights on HB series
dampers. This is not intended to be used to modification for use as pressure relief damper.

Heavy Duty/Industrial backdraft damper are adjusted
for the specified flow direction at the factory. The
external counterbalance is adjusted for “easy operation”.
These instructions address adjustment of the blade
counterbalance for the following:

• Damper mounting orientation and/or flow direction has
changed in the field

• Damper requires excessive start-open pressure or does
not close

• Blade seal has been removed in the field

• Counterbalance settings have been erroneously
“adjusted” in the field

Single section wide dampers will have external blade
counterbalance on one (linkage) side of damper. Dampers
with two sections will have linkage on both sides of
damper assembly. Arms are usually mounted on every
other axle, starting at the bottom, until the magnitude
of the counterbalance requires arms on every axle. The
steel airfoil models HB-230 and HB-330 will require more
counterbalance weights than model HB-120 with single
thickness blade or models HB-110 and HB-240 with
aluminum blades. The longer arms are angled so they
will nest when installed on every axle. Greenheck policy
is to distribute counterbalance evenly among blades to
minimize linkage loading and to improve blade closure.

Damper Maintenance

Greenheck's dampers are designed to be trouble free and hassle free under normal operation. Dampers are to be installed
square and straight so as to prevent binding during operation. The following annual damper maintenance suggestions will
help to insure proper damper operation and increase the life expectancy of the damper.

Foreign Matter Over the course of time, dirt and grime may collect on damper surfaces. The damper

surfaces should be cleaned to prevent hindrance to airflow.

Moving Parts Make sure that parts such as linkage, bearings, blades, etc. that are intended to move

freely, can do so.

Bearings. Plastic and pressfit ball bearings (without grease fittings) do not require

lubrication. Ball bearings with grease fittings should be lubricated as follows:

Maximum Duct
Temperature

°F °C Lubricant Minimum Frequency

250 121 NLGI Grade 2 lithium

12-hydrostearate grease

Closure Remove foreign materials that may be interfering with blade closure or effective sealing

of the blades with each other or with the frame. Inspect blade seals yearly and replace as
necessary.

Operation While operating the damper through its full cycle, check to see that the blades open and

close properly. If there is a problem, check for loose linkage.

twice a year

Counterbalance Adjustment Instructions

1. Adjust FULL OPEN blade stop first. On most models,
a bolt with a spacer is used through the top linkage
clevis arm. Open and close damper to verify there is no
interference between axles and the nested counterweight
arm.

2. Place damper in the installed mounting position and flow
direction.

3. Adjust blade counterbalance at full open position first.
Fan (flow) must not be operating. Rotate damper blades
open. the crankarms or counterweight arms are generally
180° from the damper blade centerline. On very small
dampers with aluminum blades, the crankarm may be
inclined towards damper outlet, due to the torque of the
linkage. Adjust counterweight plate center distance until
blades will start to close from full open position. Moving
plate(s) out will increase counterbalance. It may be
necessary to add or delete a plate. Counterweight plate
quantity per arm should not vary by more than one and
the distance outward from the axle centerline should not
vary more than 1/2 inch among counterweight arms.

4. Close damper. Blades should close completely (you
can feel the blade edge seals make contact) without
slamming. NOTE: Counterweight arms are welded to the
axles as shipped. Arm adjustment will require weld to be
removed and to be rewelded after modification.

• If closing too hard, loosen arm fastener to the axle and

rotate top of arm towards upstream of air entering side.
Retighten fastener.

• If not closing, loosen the arm fastener to the axle and

rotate top of arm towards downstream or discharge.
Retighten fastener.

Counterbalance weight assembly

(square axle units)

Counterbalance arm assembly

(long & short arm)