Installation Guide

20
7. BALANCING THE UNIT (CONT’D)
7.4 BALANCING CHART AND PRESET SPEEDS TABLE (CONT’D)
Use the balancing chart to convert pressure (in. w.g.) values read from magnehelic gauge to airflow (CFM) values. While balancing,
the VT9W wall control screen shows which pressure taps have to be used. See example below.
FLOW FRESH STALE
CFM IN. W.G. IN. W.G.
120 0.71 0.73
125 0.67 0.70
130 0.63 0.67
135 0.59 0.64
140 0.55 0.61
145 0.51 0.58
150 0.47 0.55
UNIT BALANCING CHART
Plug magnehelic gauge
tubing to STALE airflow.
Plug magnehelic gauge
tubing to FRESH airflow.
STALE reading value with
its corresponding CFM
FRESH reading value with
its corresponding CFM
NOTE: The unit is considered balanced even if there is a difference of ± 10 CFM (or ± 5 L/s or 17 m³/h) between the two airflows.
PRESET SPEEDS TABLE
The special design of these units, combined with the VT9W main wall control, offer many preset speeds ranges according
to the unit models.
See preset speeds table example below.
UNIT MODEL
P
RESET
SPEEDS NO.
H
IGH SPEED
(CFM@ 0.4 IN. W.G.)
LOW SPEED
(CFM@ 0.2 IN. W.G.)
20/40/60
MIN.
C
ONTROL STALE AIR
(CFM@ 0.4 IN. W.G.)
R
ECIRCULATION SPEED
(CFM@ 0.4 IN. W.G.)
__
From 60 to 250
From 30 CFM to
75% of adjusted
TURBO speed
From 60 to 250 From 60 to 250
01 250 125 250 250
02 225 110 250 225
03 200 100 250 200
04 175 85 225 175
05 150 75 200 150
06 125 60 175 125
07 100 50 150 100
08 This speed must be used for HVI testing at 64 CFM @ 13°F (-25°C)
09 This speed must be used for HVI testing at 98 CFM @ 13°F (-25°C)
CONT
TURBO