Dacor DHD U790LS/DA Series, Installation Instructions Manual

ENGLISH

8

Installation Requirements

Venting requirements

•  Vent system must terminate outdoors.
•  Do not terminate the vent system in an attic or other 

enclosed area.

•  Do not use a 4” (10.2 cm) laundry-type wall cap.
•  Use metal vent only. Rigid metal vent is 

recommended.

•  Plastic or metal foil vent is not recommended.
•  The length of the vent system and the number of 

elbows should be kept to a minimum to provide 

efficient performance. For the most efficient and 

quiet operation:

 -Use no more than three 90° elbows.
 -Make sure there is a minimum of 30” (76.2 cm) 

of straight vent between the elbows if more than 1 

elbow is used. Do not install 2 elbows together.

• 

Use clamps to seal all joints in the vent system.

•  The vent system must have a damper. If the roof 

or wall cap has a damper, do not use the damper 

supplied with the hood.

•  Use caulking to seal the exterior wall or roof opening 

around the cap.

•  The size of the vent should be uniform.

Venting methods

To use the hood’s top outlet to vent your hood, a 10” (25.4 

cm) round vent system is required. This vent system is not 

included and must be purchased separately.

NOTE

Flexible vent is not recommended. Flexible vent creates 

back pressure and air turbulence that greatly reduces 

performance. The vent system can terminate either 

through the roof or wall. 
Always install a metal vent cover where the ductwork 

exits the house. Hood must be vented to the outside of 

building only.

Discharge direction

This hood is factory set for venting through the roof 

(vertical discharge) or wall (horizontal discharge). 
To vent through a wall, a 90° elbow is needed.

Ductwork installation guidelines

For safety reasons, ducting should vent directly outdoors 

(not into an attic, underneath the house, into the garage 

or into any enclosed space). Do not exceed 50 ft (15.24 m) 

of duct. Keep duct runs as short and straight as possible. 

Elbows and transitions fittings reduce air flow efficiency. 

Back to back elbows and “S” turns give very poor delivery 

and are not recommended. A short straight length of duct 

at the inlet of a remote fan gives the best delivery. 

Ducting recommendations

Proper performance is dependent upon proper ducting. 

Cold weather

Cold weather installations should have an additional 

backdraft damper installed to minimize backward cold 

air flow and a nonmetallic thermal break to minimize 

conduction of outside temperatures as part of the 

ductwork. The damper should be on the cold air side 

of the thermal break. The break should be as close as 

possible to where the ducting enters the heated portion 

of the house.

Make-up air

Local building codes may require the use of make-up air 

systems when using ducted ventilation systems greater 

than specified CFM of air movement. The specified CFM 

varies from locale to locale. It is the responsibility of 

the owner and the installer to determine if additional 

requirements and/or standards apply to specific 

installations.