Maytag MDG120 - Manual (Page 12)

IMPORTANT: For extended duct work runs, the
cross section area of the duct work can only be
increased to an extent. Maximum proportional
duct work runs
cannot exceed twenty (20) feet
more than the original limitations of twenty (20)
feet with two (2) elbows. When the duct work
approaches the maximum limits as noted in this
manual, a professional heating venting air
conditioning (HVAC) firm should be consulted
for proper venting information.
IMPORTANT; DO NOT use screens, louvers, or
caps on the outside of opening of exhaust duct
work
MULTIPLE DRYER (COMMON)
VENTING
If it is not feasible to provide separate exhaust
ducts for each dryer, ducts from individual
dryers may be channeled into a “common main
duct.” The individual ducts should enter the
bottom or side of the main duct at an angle not
more than 45° in the direction of air flow and
should be spaced at least 48-% inches apart.
The main duct should be tapered, with the
diameter increasing before each individual 14-
inch (minimum) duct is added.
IMPORTANT: The MDG120 is not provided with
a back draft damper. When exhausted into a
multiple (common) exhaust line, a back draft
damper
must be installed at each dryer duct.
IMPORTANT: No more than four (4) dryers
should be connected to one main common
duct.
The main duct may be any shape or cross sec­
tional area, so long as the minimum cross section
area is provided. See the illustrations showing
the minimum cross section area for multiple dryer
round or square venting. These figures must be
increased 10 square inches when rectangular
main ducting is used, and the ratio of duct width
to depth should not be greater than 3 -V 2 to 1.
These figures must be increased in proportion if
the main duct run to the last dryer to where it
exhausts to the outdoors is unusually long (over
20 feet) or has numerous elbows (more than two
[2]) in it. In calculating duct work size, the cross
section area of a square or rectangular duct
must
be increased 20 percent for each additional 20
feet. The diameter of a round exhaust must be
increased 10 percent for each additional 20 feet.
Each 90° elbow is equivalent to an additional 30
feet and each 45° elbow is equivalent to an
additional 15 feet.
MULTIPLE DRYER VENTING WITH
14” DIAMETER (2,150 CFM) EX­
HAUST CONNECTIONS AT COM­
MON DUCT
VtRTlCAL OUCTHa
NO. OF ORrSRS i 1
HKlijHThoss «5 380 299 119
ÄMHüH WÍW ■
DUCT DIAMETCR <KI 2< 22 te U
MOWIZOKTAU OUCTWO
Д18-Д.-V - _l
2X0 aSARANCE
MQN--------- r
I-<9 3/8’
2X0 CLEARANCE
IMPORTANT: NO MORE THAN 4 DRYERS
CAN BE CONNECTED TO ONE COMMON
DUCT (VENT).
FORMULAS TO CALCULATE DUCTING CROSS
SECTIONAL AREA
CROSS SECTIONAL AREA OF A ROUND
DUCT = .785 X D2 WHERE D = DIAMETER
OF THE DUCT
o
CROSS SECTIONAL AREA OF A RECTANGULAR
DUCT = WXH WHERE W= WIDTH AND H =
HEIGHT I
NOTE A: OPENING MUST BE TWO (2) INCHES
LARGER THAN DUCT (ALL THE WAY AROUND) THE
DUCT MUST BE CENTERED WITHIN THIS OPENING
IMPORTANT: For extended duct work runs, the
cross section area of the duct work can only be
increased to an extent. Maximum proportional
duct work runs cannot exceed twenty (20) feet
more than the original limitations of twenty (20)
feet with two (2) elbows. When the duct work
approaches the maximum limits as noted in this
manual, a professional HVAC firm should be
consulted for proper venting information.
IMPORTANT: Exhaust back pressure
measured by a manometer at each dryer
exhaust duct area
should not exceed 0.3
inches of water column.
12