Balancing Rocedure; What You Need To Balance The Unit; Preliminary Stages For Balancing The Unit; Installation Of Flow Collar - NuTone GSEH3K Installation Instructions Manual

8. BALANCING PROCEDURE (GSVH1K, GSHH3K AND GSEH3K UNITS ONLY)
All units are prebalanced. However, if your construction code requires to balance the unit, follow this procedure.
8.1 W Y N
HAT OU EED TO
• A magnehelic gauge capable of measuring 0 to 0.5 inches water gauge (0 to 125 Pa)
and 2 plastic tubes.
• Two flow collars (the size will vary depending of duct diameter).
8.2 P S
RELIMINARY
Seal all the unit ductwork with tape. Close all windows and doors. Turn off all exhaust devices such as: range hoods, dryers and
bathroom fans. Make sure balancing dampers are fully open (F and G in figure below).
Choose an appropriate location for the 2 flow collars according to figure below:
• On the exhaust air duct (first measuring location, A)
• On the fresh/filtered air distribution duct (second measuring location, B)
• At least 36" (914 mm) away from the unit; at least 12" (304 mm) before or after 90° elbow and at least 12" (304 mm) away from a register.
• At least 12" (304 mm) away a from a balancing damper (F and G in figure below).
12¨(304mm)
VP0014A
8.3 I
NSTALLATION OF
Insert the flow collars in the ducts at each location (A et B on figure above). Make sure their arrows are pointing in the direction of the
airflow. Tape collars in place temporarily.
8.4 B P
ALANCING ROCEDURE
1. Set the unit to high speed.
Make sure that the furnace blower is ON if the installation is in any way connected to the ductwork of the cold air return. If not leave
furnace blower OFF.
2. Place the magnehelic gauge on a level surface and adjust it to zero.
3. Connect tubing from gauge to flow collar in exhaust air stream (location A in illustration above). Be
sure to connect the tubes to their appropriate high / low fitting. If the gauge reading drops to below
zero, reverse the tubing connections.
NOTE: It is better to start with the exhaust air flow reading because the exhaust typically has more
restriction than the fresh air, especially in cases of stand alone and central draw point installations.
Hold or place the magnehelic gauge upright and level. Record the reading.
4. Move tubing to the other side of the unit (location B in illustration above and note reading. Adjust the fresh
air balancing damper F until the reading at B is approximately the same as the reading at A. If the reading
at B is less than the reading at A then go back and adjust the exhaust balancing damper G to equal the
fresh air flow.
5. Remove flow collars and reconnect the duct, then, seal with duct tape. Write the required airflow information on a label and stick it
near the unit for future reference: (date, maximum speed airflows, your name and phone number and business address).
NOTES: 1. Most flow collar kits provide a conversion chart situated on the collar which enables you to convert magnehelic gauge readings
to equivalent cfm values.
2. A difference of ± 10 cfm ( ± 0.015 inches water gauge) between the 2 readings is considered balanced.
3. If you are using only one flow collar, then, after completing the first reading, transfer this measuring device to the other side
of the unit and take the second reading.
B U
ALANCE THE NIT
B
TAGES FOR ALANCING THE
OR
12¨(304mm)
B
12¨(304mm) 36¨(914mm)
F C
LOW OLLAR
U
NIT
F
- 32 -
Flow collar
VP0005
12¨(304mm)
G A
36¨(914mm)
FRONT DOOR
VP0003
VP0004