Filter
Top Products
Rinnai Corporation Hydronic Furnace (37AHB) Manual 9
Installation
DUCT CONNECTIONS
Supply Duct
The supply ductwork must be attached to the outside
of the flange on the air discharge end of unit. Flexible
connectors may be used if desired.
Return Duct
The return ductwork should be attached to the air
return side (bottom or side) of unit using sheet metal
screws or other fasteners.
For side return air inlet installation see the Figures 3
and 4.
FILTER INSTALLATION
Internal filter rack and a 1 inch disposable filter are
standard on all models. Refer to the Specifications
section for dimensions.
AIR SYSTEM
Existing Ductwork
It is the responsibility of the installer to inspect all
previously installed air distribution systems to
determine its suitability for the new heating and/or
cooling system. Existing ductwork may have to be
modified and/or insulated to provide satisfactory air
distribution.
Ductwork Installation
Connect the supply-air duct over the outside of 3/4-in.
flange on the unit’s discharge side. Secure the duct to
the flange with proper fasteners for the type of duct
used. Support the duct independently.
Use flexible connectors (if desired between the
ductwork and the unit to prevent transmission of
vibration.
Use insulation with vapor barrier for ductwork passing
Attachment Methods Using Straps
Method 1
Use (4) #8 x 3/4 sheet metal screws for each strap.
Straps to be vertical against the unit’s sides and not
allowed to be pulled away from the sides.
Method 2
Fold all straps under the furnace and secure with (4)
#8 x 3/4 sheet metal screws (2 screws at the side and
2 screws at the bottom. (Care must be taken not to
drive the screw through the coil.)
Figure 7: Horizontal Unit Suspension with Straps
The air inlet is not allowed to be at
the front or back of the furnace
Front
Back
Do not position the furnace on its
back or with it face down.
COIL
INTERFACE
AREA
PROHIBITED INSTALLATIONS
Figure 8:
Figure 9:
NOTE:
Multiple Furnace configured for installation with a
single Rinnai Tankless Water Heater is prohibited.
DOOR
ASSEMBLY
1 INCH x 22 GAUGE
GALVANIZED STRAPS
TYPICAL FOR 4 STRAPS
RETURN AIR
OPENING
SUPPLY AIR OPENING
BACK OF UNIT