20
Flex Fuel Owner’s Manual
March 2011
5: Installation
5.7 Connecting to Heating System
Existing Forced Air
A water to air heat exchanger is inserted in the existing plenum. In most cases the heat exchanger is placed
in a horizontal position, keeping all four sides level. The air must be forced through the finned area of the
heat exchanger evenly. The hot water line coming from the hot-water tube enters the bottom fitting of the
heat exchanger and exits the top fitting, which returns to the furnace. If the plenum is too large or too small,
it must be altered to fit the heat exchanger properly.
Note: The Water to Air Heat Exchanger must be installed below any existing
Off-Peak electric coils already in the plenum.
After the installation of the WoodMaster add-on water to air exchanger, the air flow may need to be in-
creased to fuel furnaces, electric furnaces, and electric/gas furnaces. Contact your dealer for assistance.
Existing Hot Water Heat
A Water to Water Heat Transfer Unit is used to connect to an existing hot water boiler system.
Note: Any changes that are made to an existing boiler should be done by a qualified
plumber and follow all state and local codes.
Hot Water Supply from Flex fuel
(Always put supply in lower port.)
Cold Water Return to
Flex fuel
Hot Water Supply from
Flex fuel
Cold Water Return to
Flex fuel
Existing Heat
Zone Return
WoodMaster Water to
Water Heat Transfer Unit
Circulating Pump
for Existing Hot
Water Heating
System
Existing Hot
Water Boiler