Thermo Pride MODEL OPA User Manual
Page 67

All installations and services must be performed by qualified service personnel.
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This procedure can be repeated to determine the airflow for each room in the
residence. The results of these calculations are given in Table 6, below.
Table 6: Required Room Air Flowrates Based on Floor
Area for Example 2
We will assume the airflow is approximately equally split between all registers in
a particular room. This completes steps (a) through (d) of the duct sizing method.
For step (e), static pressure drops for each system, branch, and component must
be selected. Since the appliance circulating blower can only tolerate a maximum
pressure of 0.4 in. W.G., the combined resistance of the supply and return air
systems cannot exceed this amount.
Room
Room
Floor Area
(Sq. Ft.)
Room Air
Flowrate
(CFM)
Number of
Registers
Flowrate per
Register
(CFM)
Living
400
350
3
1 @ 120
2 @ 115
Dining
120
105
1
105
Kitchen
144
126
1
126
Master
Bedroom
360
315
2
2 @ 157
Bedroom
224
196
1
196
Bedroom
224
196
1
196
Master
Bathroom
64
56
1
56
Bathroom
64
56
1
56
Total
1600
1400
11