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Installer’s Guide
18-CD21D1-5 3
Installation Instructions 3
General Installation Instructions 4
Location and Clearances 4
Outline Drawing 5
Upflow Installation 7
Downflow Installation 7
Air For Combustion and Ventilation 8
Duct Connections 10
Return Air Filters 11
Typical Upflow Return Air Filter Installations 11
Alternate Upflow Filter Clip / Bracket Installation 13
Typical Downflow Furnace Return Air Filter Installations 13
General Venting Instructions 14
Venting Into a Masonry Chimney 15
Electrical Connections 16
Field Wiring Diagrams 17
Gas Piping 19
Sequence of Operation 19
Start Up and Adjustment 20
Preliminary Inspections 20
Combustion and Input Check 20
High Altitude Derate 21
Lighting Instructions 22
Control and Safety Switch Adjustment 23
IFC Error Flash Codes 24
Abnormal Conditions 24
Contents
▲
WARNING
!
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could re-
sult in serious injury, death or property damage.
Improper servicing could result in dangerous opera-
tion, serious injury, death, or property damage.
Safety signal words are used to designate a degree or
level of seriousness associated with a particular hazard.
The signal words for safety markings are WARNING,
and CAUTION.
a. WARNING indicates a potentially hazardous situa-
tion which, if not avoided, could result in death or
serious injury.
b. CAUTION indicates a potentially hazardous situation
which, if not avoided, may result in minor or mod-
erate injury. It is also used to alert against unsafe
practices and hazards involving only property dam-
age.
▲
CAUTION
!
To prevent shortening its service life, the furnace
should not be used as a “Construction Heater” during
the finishing phases of construction until the require-
ments listed in item 9, a-g of the safety section of this
publication have been met. Condensate in the pres-
ence of chlorides and fluorides from paint, varnish,
stains, adhesives, cleaning compounds, and cement
create a corrosive condition which may cause rapid de-
terioration of the heat exchanger.
▲
WARNING
!
These furnaces are not approved or intended for instal-
lation in manufactured (mobile) housing, trailers, or
recreational vehicles.
Failure to follow this warning could result in property
damage, personal injury, or death.
▲
CAUTION
!
Do NOT install the furnace in a corrosive or contami-
nated atmosphere.