When selecting the fan mounting location, the following criteria should be considered: a) type of application; b) proximity to fresh air intakes; c) sound created by fan operation.

a) For dryer boosting applications, fan must be mounted a minimum of 12 linear feet from the dryer outlet. If the fan is mounted closer than the recommended 12 feet, it will develop enough pressure to pull wet lint through the duct system causing buildup on the impeller and clogging of the vents in the discharge cover. Important Notice: To prevent the possibility of fire hazards when using a booster fan in conjunction with a gas fired dryer, booster fan flow must not exceed the dryer fan capacity. Typical resident dryer fans produce 160 cfm.

For range venting applications, sufficient access for periodic cleaning of exhausted grease from the wall and fan discharge cover should be provided.

b) With any exhaust system, the fan should be located a minimum of 6 feet horizontally and 8 feet vertically from any fresh air intakes for HVAC systems, heat recovery systems, etc. to prevent re-entrainment of exhaust air streams. Windows that are frequently opened during moderate seasons may also be considered fresh air intakes.

c) Although system noise at the point of exhaust will be virtually silent, windows and other structural openings may be sources for noise entry during fan operation. Proximity to windows and openings should be considered. Select the location on the exterior wall where the fan is to be mounted. Make a hole through the wall that is 1/2” larger than the diameter of the fan duct connection collar. A short piece of rigid duct (not included) approximately 2” longer than the wall thickness is recommended for use as an extension through the wall.

a) Whenever the duct passes through an unconditioned space, it is recommended that insulated ducting be used. This will prevent the possibility of condensation building up both within the duct and on the exterior duct wall, this is particularly true when the fan is used as bathroom exhaust where high levels of moisture in the air stream is common.

b) Insulated flexible duct, as used for take-offs in residential heating and air conditioning systems, is recommended. Since the fans are capable of overcoming the higher resistance created by long duct runs and flexible duct work, the system will not see an appreciable loss of performance. However, when using flexible duct, it should be stretched as straight and tight as possible to minimize losses.

c) When connecting duct work to the fan, grills, or transitional devices, make as air tight a connection as possible to prevent leakage of moisture, odors or other contaminants which are being exhausted.

Please note: When installing the RVF units, an extra 1” diameter should be added to the “Dia.” dimension to determine proper through-the-wall hole size in order to allow adequate space for duct connection. Also, a high quality caulk capable of adhering to masonry and sheet metal should be used behind the housing backplate to assure a leak proof connection between fan housing and wall.