User guide

1220 Watson Center Road • Carson, CA 90745
Tel: [phone] • Fax: [phone]
www.anemostat.com • [e-mail]
11
Minimum and Maximum Airflow Settings
REFER TO THE CONTROLS MANUAL CM-1 FOR THE PROPER FIELD ADJUSTMENT
OF THE MINIMUM AND MAXIMUM AIRFLOW SETTINGS ON TERMINALS PROVIDED
WITH PRESSURE INDEPENDENT CONTROLS.
Some adjusting tips:
1. Allow sufficient time for the controller to respond to adjustments.
2. Cycling of the thermostat to check maximum and minimum airflow settings is often
required.
3. On units with pneumatic controls, do not turn the adjustment knobs excessively.
Altitude Correction Factors
Barometric
Pressure Altitude Density Correction
(in h.g.) (feet) lb/ft
3
Factor
29.92 0 .075 1.03
20.28 500 .074 1.01
28.85 1000 .072 0.99
28.33 1500 .071 0.98
27.82 2000 .070 0.96
27.32 2500 .068 0.95
26.81 3000 .067 0.93
26.33 3500 .066 0.91
25.84 4000 .065 0.89
25.37 4500 .064 0.88
24.89 5000 .062 0.86
24.44 5500 .061 0.85
23.98 6000 .060 0.83
23.54 6500 .059 0.82
23.09 7000 .058 0.80
Example: Determine the airflow sensor signal of a 6” unit at 500 CFM located
at an elevation of 5000 ft., for a 3000 series pneumatic controller.
To use the correction factor:
Correction factor X CFM at unit location = .86 x 500 = 430 CFM
Referencing the 6” flow curve, shown on page 10, find 430 CFM @ .80” w.c.
sensor signal pressure. The velocity controller set at .80” signal pressure will
result in 500 CFM at 5000 ft. elevation.
Notes:
1.Minimum and maximum airflow with pressure independent controls based on the
following
flow sensor signals:
Model 51 Controller - 1 VDC – 10 VDC
Model 31 Controller - 0.03” w.g. – 1.0” w.g.
Models 23, 24 Controllers - 0.04” w.g. – 1.0” w.g.
2.Settings below the minimum are not recommended for accurate control when using
pressure independent controls. Minimum airflow for pressure dependent applications is
0 cfm.
3.Pressure independent controls may be set for 0 CFM, at or above the minimum airflow
shown in table 4, but not between.
4.Model 23 controller available as direct acting for normally open or model 24 controller
available as reverse acting for normally closed damper positions. Factory set non-field
adjustable start point and reset span.
5.Model 31 controller can be used either as direct or reverse acting for normally open or
normally closed damper positions. Field adjustable start point and reset span.
6.Models 23, 24, 31 controllers equipped with separate adjustable knobs for maximum
and minimum airflow settings.
7.Model 51 electronic analog controller maximum and minimum airflow settings field
adjustable at the thermostat.
Control Inlet Min Airflow Max Airflow
1
Type Size (CFM) (CFM)
Model 51 5 22 305
Electronic 6 45 470
Analog 7 70 635
Controller 8 90 835
9 115 1100
10 145 1355
12 155 1740
14 250 2300
16 447 3390
24x16 650 6480
Model 31 5 50 287
Pneumatic 6 81 469
Controller 7 106 612
8 150 867
9 190 1098
10 234 1353
12 312 1802
14 428 2469
16 583 3366
24x16 1101 6358
Models 23, 24 5 57 287
Pneumatic 6 94 469
Controllers 7 122 612
8 173 867
9 220 1098
10 271 1353
12 360 1802
14 494 2469
16 673 3366
24x16 1272 6358
1
Airflow rates above maximum shown are available. Contact your Anemostat representative for application assistance.