1-800-533-7533
Quest
DRY
150 Installation, Operation and Maintenance Instructions
www.thermastor.com
quest
Asset Protection and IAQ Solutions
quest
FOR HVAC INSTALLER ONLY
In cold climates or areas where the outdoor dew point is low at times, ventilation can be used to dehumidify
the structure. This is accomplished by bringing the dry, low dew point air into the structure during these
times. This approach is often more economical than running the dehumidifier to remove excess moisture
from the structure. In cold climates, it is critical to adequately ventilate to reduce the inside moisture
content to avoid moisture accumulating in the wall cavities. For example; in a structure that experiences
condensation on the interior surface of the windows during the winter, increasing the amount of ventilation
will often cure the problem.
An insulated 6" diameter duct is generally sufficient to provide up to 125 CFM of outside air. Large quantities
of outside air will either positively or negatively impact the performance of the Quest
DRY
150, depending
upon inside and outside air conditions. Consult the factory by calling 1-800-533-7533 for recommendations
regarding the use of higher flows with your specific application.
The outside air duct should be connected to the 6" round collar on the filter enclosure of the unit. The 6"
round collar includes a manual damper. Adjust the manual damper to provide the desired amount of fresh
air for ventilation. The amount of fresh air should be based on the size and occupancy of the residence.
If you are unsure of your ventilation air requirements, consult the factory by calling 1-800-533-7533 for
assistance.
3.4D Installation in a Basement or Crawlspace with an Existing Forced Air HVAC System
It is recommended that a new, separate return duct be installed for the Quest
DRY
150 from a central area of
the structure. If this is not possible, and if the existing system has multiple returns, select one to disconnect
from the existing forced air system and use it for the dedicated Quest
DRY
150 return. Always select a return
from a central location in the structure in an area that is always open to the rest of the structure. Do not use a
return from a room that may have its door closed much of the time.
If the structure in which the Quest
DRY
150 is to be installed has an existing forced air HVAC system, utilize
the HVAC system to make the Quest
DRY
150 installation easier.
Basement Installation:
Install a separate 10" return for the Quest
DRY
150 in a central area of the structure.
Duct the supply of the Quest
DRY
150 to an optional 10" x 10" x 10" tee/damper that is 20% open to the
basement. This allows the ability to discharge a variable amount of dehumidified air into a basement that
may not be well served by the existing duct system. Duct the other side of the tee to the air supply of the
existing HVAC system. A back draft damper is required in the duct between the 10" tee and the central
supply duct to prevent air from being discharged into the basement during central fan operation. Connect
a duct from outside to the 6" collar of the
Quest
DRY
150 if you wish to provide fresh air
ventilation.
Crawl Space Installation:
Install a separate
return for the Quest
DRY
150 in a central area
of the structure. Duct the supply of the Quest
DRY
150 to a 10" x 10" x 10" tee/damper that
is 20% open to the crawl space if desired. Duct
the other side of the tee to the air supply of
the existing HVAC system ventilation. Connect
an insulated duct from outside to the 6" collar
of the Quest
DRY
150 if you wish to provide
optional fresh air.
FOR HVAC INSTALLER ONLY
