Brochure
6
Blower Performance Data - Downow
GDD80-
Model
Htg
Input
BTUH
Motor
Speed
External Static Pressure (Inches Water Column)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise
-054A3 54K
High* 1375 29 1340 30 1300 31 1270 31 1225 33 1175 34 1115 36 1035 39
Med Hi 1155 35 1130 35 1110 36 1085 37 1055 38 1015 39 975 41 910 44
M-Low
†
790 51 775 52 765 52 750 53 730 55 700 57 665 60 610 66
Low 650 62 640 63 630 63 610 66 590 68 565 71 530 75 480 83
-072B4 72K
High* 1610 33 1590 34 1575 34 1560 34 1540 35 1495 36 1460 37 1415 38
Med Hi 1295 41 1275 42 1260 42 1250 43 1220 44 1195 45 1170 46 1120 48
M-Low
†
1155 46 1135 47 1115 48 1095 49 1065 50 1040 51 1015 53 980 54
Low 910 59 885 60 860 62 835 64 810 66 785 68 765 70 735 73
-090B4 90K
High* 1675 40 1655 40 1640 41 1620 41 1590 42 1560 43 1520 44 1475 45
Med Hi 1330 50 1315 51 1300 51 1280 52 1255 53 1230 54 1200 56 1150 58
M-Low
†
1180 56 1165 57 1150 58 1135 59 1115 60 1090 61 1060 63 1010 66
Low 940 71 925 72 900 74 880 76 850 78 825 81 795 84 760 88
-108C5 108K
High* 2395 33 2335 34 2285 35 2230 36 2200 36 2140 37 2080 38 2000 40
Med Hi 2190 37 2135 37 2115 38 2080 38 2030 39 1975 41 1915 42 1810 44
M-Low
†
1785 45 1770 45 1740 46 1725 46 1685 47 1645 49 1615 50 1565 51
Low 1145 70 1110 72 1070 75 1035 77 1000 80 950 84 905 88 835 96
-126D5 126K
High* 2445 38 2395 39 2385 39 2330 40 2275 41 2225 42 2130 44 2015 46
Med Hi 2195 43 2170 43 2140 44 2120 44 2090 45 2030 46 1975 47 1855 50
M-Low
†
1795 52 1780 52 1770 53 1760 53 1725 54 1690 55 1655 56 1610 58
Low 1480 63 1475 63 1450 64 1440 65 1440 65 1415 66 1405 66 1375 68
NOTES: 1. Temperature rises in the table are approximate; actual temperature rises may vary.
2. Temperature rises in shaded areas are for reference only; these conditions are not recommended.
* Factory set cooling speed
†
Factory set heating speed
Downow GDD Accessories
5
Clearances to Combustible Materials
This furnace is Design Certifi ed in the U.S. and Canada
by CSA International for the minimum clearances to
combustible materials. NOTE: The furnace is listed for
installation on combustible or non-combustible fl ooring.
However, wood is the only combustible fl ooring allowed
for installation. Downfl ow models must use the appropriate
subase kit when installing over a wood fl oor. To obtain
model number and specifi c clearance information, refer
to the furnace rating plate, located inside of the furnace
cabinet.
Access for positioning and servicing the unit must be
considered when locating unit. The need to provide
clearance for access to panels or doors may require
clearance distances over and above the requirements.
Allow 24 inches minimum clearance from the front of
the unit. However 36 inches is strongly recommended.
See Table 1 for minimum clearance requirements.
Table 1. Minimum Clearances to
Combustible Materials
CLEARANCES TO COMBUSTIBLE MATERIALS
Left Side..................0 Inches Top ..........................0 Inches
Right Side ...............0 Inches Front ......................
†
4 Inches
Vent ......................... 0 Inches Back ........................0 Inches
†
Allow 24 in. minimum clearance for servicing. Recommended
clearance is 36 in.
UPFLOW & DOWNFLOW
APPLICATIONS
HORIZONTAL
APPLICATIONS
BACK
FRONT
LEFT SIDE
RIGHT SIDE
VENT
VENT
SIDE
TOP
BOTTOM
SIDE
TOP
FRONT
The information listed below is for reference purposes only
and does not necessarily have jurisdiction over local or state
codes. Always consult with local authorities before installing
any gas appliance.
Combustion and Ventilation Air
• US: National Fuel Gas Code (NFGC), Air for Combustion
and Ventilation
• CANADA: Natural Gas and Propane Installation Codes
(NSCNGPIC), Venting Systems and Air Supply for
Appliances
Duct Systems
• US and CANADA: Air Conditioning Contractors Association
(ACCA) Manual D, Sheet Metal and Air Conditioning
Contractors National Association (SMACNA), or American
Society of Heating, Refrigeration, and Air Conditioning
Engineers (ASHRAE) Fundamentals Handbook
Electrical Connections
• US: National Electrical Code (NEC) ANSI/NFPA 70
• CANADA: Canadian Electrical Code CSA C22.1
Gas Piping and Gas Pipe Pressure Testing
• US: NFGC and National Plumbing Codes
• CANADA: NSCNGPIC
General Installation
• US: Current edition of the NFGC and the NFPA 90B. For
copies, contact the National Fire Protection Association
Inc., Batterymarch Park, Quincy, MA 02269; or American
Gas Association, 400 N. Capitol, N.W., Washington DC
20001 or www.NFPA.org
• CANADA: NSCNGPIC. For a copy, contact Standard
Sales, CSA International, 178 Rexdale Boulevard,
Etobicoke (Toronto), Ontario, M9W 1R3 Canada
Safety
• US: (NFGC) NFPA 54–1999/ANSI Z223.1 and the
Installation Standards, Warm Air Heating and Air
Conditioning Systems ANSI/NFPA 90B.
• CANADA: CAN/CGA-B149.1 and .2–M00 National
Standard of Canada. (NSCNGPIC)
Heating Load
The furnace should be sized to provide the design heating
load requirement. Heating load estimates can be made
using approved methods available from Air Conditioning
Contractors of America (Manual J); American Society of
Heating, Refrigerating, and Air Conditioning Engineers;
or other approved engineering methods. Excessive
oversizing of the furnace could cause the furnace
and/or vent to fail prematurely.
The ductwork should be appropriately sized to the capacity
of the furnace to ensure its proper airfl ow rating. For
installations above 2,000 ft., the furnace should have a
sea level input rating large enough that it will meet the
heating load after deration for altitude.
Clearances
Left Side .................. 0 inches
Right side ................0 inches
Vent ......................... 0 Inches
CLEARANCES TO COMBUSTIBLE MATERIALS
Top ..........................0 inches
Front ...................... 4* inches
Back ........................ 0 inches
*Minimum clearance for servicing is 24 inches; the
recommended clearance is 36 inches.
Part No. Description
902974 Downflow sub base kit, 14 ½” cabinet
904911
Downflow sub base kit, 17 ½”, 21”, and 24 ½” cabi-
nets
905028 U.S. LP conversion kit (0 to 10,000 ft.)
905029 Canada LP conversion kit (0 to 4,500 ft.)
541036 Side return filter kit
904872 Fixed Speed High Eff. Blower Kit, -054A3
904873 Fixed Speed High Eff. Blower Kit, -072B, -090B
904874 Fixed Speed High Eff. Blower Kit, -108C
904875 Fixed Speed High Eff. Blower Kit, -126D
904876 Variable Speed High Eff. Blower Kit, -054A3
904877 Variable Speed High Eff. Blower Kit, -072B, -090B
904878 Variable Speed High Eff. Blower Kit, -108C
904879 Variable Speed High Eff. Blower Kit, -126D
FLEXIBLE CATEGORY 1 VENTING: May be vented with
a dedicated venting system or vented in common with
other Category 1 appliances.