10
DETERMINE VENTILATION TIME SETTING
CALCULATING AIRFLOW REQUIREMENT
1.
The MINIMUM ventilation requirement is calculated using
ASHRAE 62�2-2010�
ASHRAE Airflow in CFM = [House Area in Sq. Ft. x 0.01] +
[(Number of Be1) x 7.5]
NOTE:
Use ‘Number of Be 1’ or ‘Number of
Occupants’, whichever is larger�
2. TABLE 3
shows the calculated airflow values to the nearest
5 CFM�
3.
Record the required CFM�
TABLE 3
– CFM REQUIRED
House
Sq. Ft.
Number of Bedrooms
2
3
4
5
6
7
1000
35
40
50
55
65
70
1500
40
45
55
60
70
75
2000
45
50
60
65
75
80
2500
50
55
65
70
80
85
3000
55
60
70
75
85
90
3500
60
65
75
80
90
95
4000
65
70
80
85
95
100
4500
70
75
85
90
100
105
5000
75
80
90
95
105
110
MEASURE VENTILATION AIR (CFM) DELIVERY RATE AND SELECT VENT TIME
1.
Measure the outdoor air flow (CFM) through the duct that is bringing in only outdoor air.
2.
Use the CFM Delivered along with the CFM required to find the Cycle Time per hour setting from
TABLE 4
. For example if the
ventilator is providing 120 CFM, and the requirement is 70 CFM, set the time to 35 minutes�
3.
Use the control knob to set the vent time to the determined minutes per hour�
NOTE:
knob can be set halfway between printed
numbers to achieve 5 minute increments�
TABLE 4
– CYCLE TIME SETTING (MINUTES) FOR AIRFLOW DELIVERED VS� AIRFLOW REQUIRED FOR 1 HOUR CYCLE
CFM Delivered
CFM Required
20
30
40
50
60
70
80
90
100
110
60
20
30
40
50
60
80
15
25
30
40
45
55
60
100
15
20
25
30
35
40
50
55
60
120
15
15
20
25
30
35
40
45
50
55
140
15
15
15
20
25
30
35
40
45
50
160
15
15
15
20
25
25
30
35
40
45
180
15
15
15
20
20
25
30
30
35
40
200
15
15
15
15
20
25
25
30
30
35
220
15
15
15
15
20
20
20
25
30
30
