Anti-Backflow Damper; Floor Installation; External Static Pressure Range - Coleman DGAA Installation Manual

129098-UIM-H-1011
NOTE: See label on coil panel for conversion and lighting instructions.
Obtain a temperature rise within the ranges specified on the name
plate.
AUTOMATIC
DAMPER
FURNACE
BASE
DUCT
CONNECTOR
NOTE: FOR BEST AIR DELIVERY INSTALL DAMPER
WITH BLADES PARALLEL TO SUPPLY DUCT.
FIGURE 11: Anti-Backflow Damper
INSTALLATION RECOMMENDATIONS
1. Remove the front panels and set the furnace onto the duct con-
nector. Slide it back until the rear of the unit engages the Iocator
bracket.
2. Secure the front of the furnace with two screws at the mounting
holes provided.
3. Secure the top of the furnace to a structural member using screw
through the strap at the back of the furnace. Strap may be moved
to any of the holes located along the top back of the furnace.
Installer may provide an equivalent method, such as screws
through the casing side.
The duct system is a very important part of the installation. If the duct
system is improperly sized the furnace will not operate properly. The
ducts attached to the furnace plenum, should be of sufficient size so
that the furnace operates at the specified external static pressure and
within the air temperature rise specified on the nameplate.
Consideration should be given to the heating capacity required and also
to the air quantity (CFM) required. These factors can be determined by
calculating the heat loss and heat gain of the home or structure. If these
calculations are not performed and the furnace is over-sized, the follow-
ing may result:
1. Short cycling of the furnace.
2. Wide temperature fluctuations from the thermostat setting.
3. Reduced overall operating efficiency of the furnace.
The supply and return duct system must be of adequate size and
designed such that the furnace will operate within the designed air tem-
perature rise range and not exceed the maximum designed static pres-
sure. These values are listed in Table 2.
SECTION II1: RETURN AIR
REQUIREMENTS
CLOSET INSTALLATIONS
Additional Requirements
Additional requirements for floor and ceiling return system for closet
installed sealed combustion heating appliance are given in the next
paragraph.
kWARNING
HAZARD OF ASPHYXIATION, DO NOT COVER OR RESTRICT
FLOOR OPENING
TABLE 2: External Static Pressure Range
Input Output
Nominal
Air Flow I
MBH kW MBH kW CFM cmm In.W.C kPa
56 16.4 45 12.9 1305 36.9 0.10 0.0249
70 20.5 56 16.4 1305 36.9 0.10 0.0249
77 22.5 62 18.0 1305 36.9 0.10 0.0249
90 26.3 72 21.1 1305 36.9 0.10 0.0249
Ext. Static Pressure
Minimum Maximum
In.W.C kPa
0.30 0.0747
0.30 0.0747
0.30 0.0747
0.30 0.0747
1. Std. Blower-High Speed-No Coil.
IMPORTANT
The air temperature rise should be taken only after the furnace has
been operating for at least 15 minutes. Temperatures should be
taken 6" (15.2 cm) past the first bend from the furnace in the supply
duct. The return air temperature must be taken at the return air Iou-
vered door. Return static pressures can be taken by pushing probe
through the air filter on the Iouvered door.
BLEND AIR INSTALLATIONS
If a blend air ventilation system is installed, the 5" (12.7 cm) diameter
knockout in the top cover must be removed. The blend air damper is to
be placed on the top cover and secured with screws as shown in Figure
12. The power wires for the Blend Air Damper are inserted through the
7/8" (2.22 cm) hole in the top cover. The wires to the Blend Air Damper
will be connected as shown in Figure 20. Refer to the Blend Air Installa-
tion Manual to complete the installation.
BLEND AIR
FLEX DUCT
BLEND AIR
DAMPER
FLOOR
FIGURE 12: Floor Installation
8 Johnson Controls Unitary Products