HR150, 200; ER150, 200 FRESH AIR VENTILATION SYSTEMS
5
68-0269
Sizing
There are several methods that can provide satisfactory
results for sizing a ventilator to provide adequate ventilation
for a home. The ASHRAE Standard 62-1989 Ventilation for
Acceptable Indoor Air Quality suggests the following:
— .35 air changes per hour (ach) but not less than 15 cfm per
person for living areas = house size (sq ft) • ceiling height
(ft) / 60 (min) •.35 (ach)
Example:
= 2000 sq ft • 8 ft / 60 min •.35 ach = 93 cfm
— 50 cfm intermittent or 20 cfm continuous capacity for
bathrooms
Example:
50 cfm intermittent • 3 bathrooms = 150 cfm
20 cfm continuous • 3 bathrooms = 60 cfm
— 100 cfm intermittent or 25 cfm continuous capacity for
kitchens
Example:
100 cfm intermittent • 1 kitchen = 100 cfm
25 cfm continuous • 1 kitchen = 25 cfm
Option 1: Fresh Air Ventilation System provides continuous
fresh air supply of 93 cfm, and intermittent capacity for
bathrooms of 150 cfm. A separate 100 cfm exhaust fan is
used for the range hood.
Supply air flow required = 93 cfm
Exhaust air flow required = 150 cfm
Any Total Comfort System ventilation unit provides suitable
ventilation capacity. See Fig. 1.
Option 2: Fresh Air Ventilation System provides continuous
fresh air supply of 93 cfm, intermittent exhaust capacity for
bathrooms of 150 cfm, and continuous kitchen ventilation of
50 cfm.
Supply air flow required = 93 cfm
Exhaust air flow required = 200 cfm
Total Comfort System HR200/ER200 have the exhaust
capacity required to meet the ventilation needs of this
application. See Fig. 1.
Mounting Position and Location
The HR150/ER150 and HR200/ER200 can be suspended
from exposed ceiling joists or the ceiling surface, or floor
mounted. The ventilator must be level for the drains to
function properly.
• Locate the fresh air intake 6 ft (2m) or more from the stale
air exhaust to avoid re-entry of the exhaust air.
• Locate the ventilator where the length of ducting required is
minimal.
Install the HR150/ER150 and HR200/ER200 in a conditioned
space using these guidelines:
• Pipe the drain line from the ventilator to a drain.
• Use an existing electrical outlet with the appropriate
current rating (or install one) close to the ventilator power
cord.
• Allow space for the drain line by placing the ventilator at
least 10 in. (254 mm) off the floor.
• For access and removal of the ventilator core, allow at
least 25 in. (635 mm) of open space in front of the unit.
Ducting
Ducting between the ventilator and the outdoors must be
insulated and have a continuous air vapor barrier. See Fig. 5.
IMPORTANT
All ducting to the outdoors must be terminated above
anticipated snow lines and be fitted with a weather
cap that incorporates bird screening.
Fig. 4. Sealing insulated duct terminations.
Design and installation of ductwork must be in accordance
with standard HVAC practice to deliver required quantities of
fresh air to the temperature-controlled space and exhaust
equivalent quantities of room air to the outside.
Keep intake and exhaust duct runs as short as possible with
few bends or elbows.
• Keep duct sizes as large as possible throughout the
installation.
• Use a 6 in. diameter round duct for all connections to and
from the ventilator.
• Separate outside intake and exhaust vents by at least 6 ft
(2m).
NOTES:
—
Do not locate the fresh air vent where it blows
directly onto occupants or the thermostat.
—
Do not locate the fresh air intake close to known
sources of pollutants such as automobile exhaust,
a dryer vent or chimney smoke.
• Ducting the supply outlet and/or the exhaust inlet of the
ventilator to the return air plenum of the air handler is an
excellent way to distribute fresh air and exhaust stale air
from all parts of the house, while reducing installation
costs. When choosing this method, balance the ventilator
when the air handler is running and interlock the ventilator
so that it can run only when the air handler runs. See
Fig. 6. An alternate method is to balance the ventilator
when the air handler is not running and let the ventilator
run whether the air handler is running or not, see Fig. 7. An
independent installation is shown in Fig. 8.
INSULATED
FLEX DUCT
COLLAR ON
VENTILATOR
SEAL INTERIOR LINING OF
FLEX DUCT TO INSIDE COLLAR
SEAL OUTER LINING OF FLEX
DUCT TO OUTER COLLAR
M6557
