Fresh Air Intake Design Recommendations - Suburban DynaPack S Series Architects And Engineers' Manual

FRESH AIR INTAKE DESIGN RECOMMENDATIONS

Suburban DynaPack A&E Manual 07/2019 Rev.6
NOTE: THE FRESH AIR INTAKE DESIGN IS ONLY FOR THE H SERIES
DYNAPACK UNITS .
1. Complete the duct design for the structure using the cfm
recommendations for each size unit. Determine the cfm for cooling,
heating and constant air circulation mode if desired. Once the duct
designs are completed for the Dynapack unit, estimate the return air
duct static pressure at the unit for cooling, heating, and constant air
circulation mode. It is expected that the return air static pressure
is negative.
2. Determine the blower speed that will be used for cooling, heating, and
continuous air circulation mode if desired. The Dynapack unit has
the option of running at the lowest speed or speed tap #1, whenever
the thermostat is switched to FAN ON. This can be accomplished by
connecting the G wire from the room thermostat directly to the #1
speed tap and bypassing the G terminal on the unit control board.
3. Determine the fresh air required for the structure using Ashrae Standard
62.2 or local codes. It may be necessary to consider the fresh air taken in
during all three modes of operation; cooling, heating, and continuous
air circulation.
4. See the charts on the following pages to determine the fresh air cfm to
be expected based on the diameter and length of the fresh air duct, the
expected return air static pressure, and the blower speed tap to be used
for cooling, heating, or continuous fan.
5. Select the fresh air duct diameter and length to supply the cfm required.
Fresh air inlet placement must be a specified distance from the furnace
flue vent. See
Figure 2
6. Use the "Load Calculation due to Ventilation" section to determine the
extra cooling load and extra heating load on the Dynapack unit due to
the addition of fresh air.
VENTILATION CALCULATION
Ashrae Standard 62.2 specifies the minimum whole building ventilation rate
as:
Qv = 0.01Acf + 7.5 (Nbr +1) where
Qv = required ventilation flow rate in cfm
Acf = building conditioned floor area in square feet
Nbr = number of bedrooms (not less than 1)
Some examples:
1400 square foot condo with 2 bedrooms equals 36.5 cfm
2000 square foot condo with 3 bedrooms equals 50 cfm
2600 square foot condo with 3 bedrooms equals 56 cfm
3200 square foot condo with 4 bedrooms equals 69.5 cfm
36
in the installation instructions.