Install Instructions

Install to Fit Your Application
Ideal when…
• Access to dedicated central return for
dehumidifier is available.
• Combined with A/C operation, requires
backdraft damper on the exhaust
port to minimize backdraft when
dehumidifier is not on but A/C is.
• (optional) Duct humidifier supply with
20% open gravity damper to provide
dry air to a specific area
Dedicated Return to Main Supply
A
MCR36852
DR120
DR90
SUPPLY
RETURN
AIR HANDLER
DEHUMIDIFIER
M36843
SEPARATE
RETURN
BACKDRAFT
DAMPER
(OPTIONAL)
GRAVITY DAMPER
DR90/DR120A3000 Dehumidification System 33-00298EFS—07
6
Flex duct is recommended in connecting to the DR90/DR120A3000 collars to reduce vibration noise.
M24745
Electrical requirements:
115 VAC outlet. Ground fault
interrupter (GFI) recommended.
Duct Sizing: Use minimum 10” diameter round for
duct lengths up to 25’ Minimum 12” required for
lengths longer than 25’ Duct branches from the main
inlet/exhaust should be minimum 10” round for 23
branches, and 12” round or larger for 4 branches or
more.
For the optional fresh air ventilator port, use 6” round,
insulated duct for lengths up to 50’
Use 8” round duct for more than 50’ of if more than
100 CFM is required.
Isolated Areas: Effective dehumidification may
require ducting to isolated or stagnant air flow areas.
Main Return to Main Supply
Ideal when…
• Running dehumidifier when not
running A/C.
• Requires damper on the exhaust port
to minimize backdraft when DR90/
DR120A3000 is not on but A/C is.
• Access to a dedicated central return is
not possible.
• System fan should run with
dehumidifier for best results.
B
SUPPLY
RETURN
AIR HANDLER
M36844
BACKDRAFT
DAMPER
DEHUMIDIFIER