Specifications

DAKA 521FB Manual Page 13 of 32 January 2009
Rev. 3, June 2013
VIII. PLANNING YOUR INSTALLATION
FIG. 7
Supplementary/
Add-On
Installation
GENERAL INFORMATION
This furnace model is designed for a conventional up flow residential central force air heating
system. It may be installed as a SUPPLEMENTARY/ADD-ON or CENTRAL FURNACE APPLICATION.
It is designed to operate with a maximum warm air duct pressure of 0.2” water column and a maximum warm air
duct temperature of 250° degrees F. The warm air supply duct system must be constructed of materials with a
minimum temperature rating of 250° degrees F. Plenums installed to the furnace must be constructed of metal.
Do not use flexible pipe.
IMPORTANT: WHETHER INSTALLED AS A SUPPLEMENTARY/ADD-ON OR CENTRAL
FURNACE, INSTALLATION OF A COLD AIR RETURN LINE IS MANDATORY.
NOTE: Any time you increase the air flow, we recommend that you increase the size of the
outlets and the cold air return line.
D. SUPPLEMENTARY/ADD-ON FURNACE APPLICATION
When installed as a Supplementary/Add-On furnace, this DAKA furnace model is designed to work in conjunction
with a conventional up flow residential central forced air heating system. See FIG. 7.
Air can be provided to the DAKA furnace through the same cold air return line that is used by the primary furnace.
This will require installation of an air line between the cold air filter box and the cold air return line of the primary
furnace.
NOTE: When used as a Supplementary/Add-On furnace, confirm that your primary furnace is capable of running
at an external static pressure greater than 0.2” W.C. This information should be found on the primary furnace
nameplate.
It can be connected in parallel to a conventional primary furnace system. Using present ductwork, the DAKA
supplementary furnace system & blower lifts the warm air from the wood-burning furnace into the plenum of the
primary furnace for distribution by the primary furnace blower. The heat produced by the wood-burning furnace
should be able to keep the room temperature above that of the setting of the primary furnace wall thermostat.
This will keep the primary furnace from burning any gas, oil, or electricity beyond what is required to run the
primary distribution blower. Should the wood fire fail to provide sufficient heat, the primary furnace will begin
operating as usual.
When used as a supplementary/Add-On furnace, a fixed back-draft damper may be required in the 8” warm duct
pipes from the DAKA furnace. They also may be needed in the plenum of the existing primary furnace.
Installation of these back-draft dampers is to prevent overheating. We recommend that once the units are
operating that both units be monitored to make sure that neither is overheating.