Sequence of Operation............................................................38
Two-Stage Heating With Single-Stage Thermostat
(Adaptive Mode)................................................................38
Two-Stage Heating With Two-Stage Thermostat
(Non-Adaptive Heating Mode) .........................................39
Cooling Mode ....................................................................39
Thermidistat Mode ............................................................42
Continuous Blower Mode .................................................43
Heat Pump .........................................................................43
Component Self-Test.........................................................43
Operate Furnace.................................................................43
Furnace Restart ..................................................................44
Adjustments.............................................................................44
Set Gas Input Rate ............................................................44
Set Temperature Rise ........................................................48
Adjust Blower Off Delay (Heat Mode)............................49
Set Thermostat Heat Anticipator ......................................49
Check Safety Controls ............................................................49
Checklist..................................................................................50
SAFETY CONSIDERATIONS
FURNACE RELIABILITY HAZARD
Improper installation or misapplication of furnace can require
excessive servicing or cause premature component failure.
Application of this furnace should be indoors with special
attention given to vent sizing and material, gas input rate, air
temperature rise, unit leveling, and unit sizing.
FIRE, EXPLOSION, ELECTRICAL SHOCK AND
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in electrical shock,
fire, personal injury, or death.
Improper installation, adjustment, alteration, service, mainte-
nance, or use can cause carbon monoxide poisoning, explo-
sion, fire, electrical shock, or other conditions which may
cause personal injury or property damage. Consult a qualified
installer, service agency, local gas supplier, or your distribu-
tor or branch for information or assistance. The qualified
installer or agency must use only factory-authorized and
listed kits or accessories when modifying this product.
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified
personnel should install, repair, or service heating equipment.
Untrained personnel can perform basic maintenance functions
such as cleaning and replacing air filters. All other operations must
be performed by trained service personnel. When working on
heating equipment, observe precautions in literature, on tags, and
on labels attached to or shipped with unit and other safety
precautions that may apply.
These instructions cover the minimum requirements and conform
to existing national standards and safety codes. In some instances,
these instructions exceed certain local codes and ordinances,
especially those that may not have kept up with changing residen-
tial construction practices. We require these instructions as a
minimum for a safe installation.
Wear safety glasses and work gloves.
CUTS AND ABRASION HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care and
wear appropriate protective clothing and gloves when han-
dling parts.
Have a fire extinguisher available during start-up and adjustment
procedures and service calls.
Recognize safety information. This is the safety-alert symbol
.
When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal injury.
Understand these signal words: DANGER, WARNING, CAU-
TION, and NOTE. These words are used with the safety-alert
symbol. DANGER identifies the most serious hazards which will
result in severe personal injury or death. WARNING signifies
hazards which could result in personal injury or death. CAUTION
is used to identify unsafe practices which may result in minor
personal injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced installation,
reliability, or operation.
INTRODUCTION
The model 58MTA, 2-Stage, 4-way multipoise, Gas-Fired, Cat-
egory IV, direct vent condensing furnace is available in model
sizes ranging in high-stage gas input rates of 60,000 to 120,000
Btuh. This furnace is C.S.A. (formerly AGA and CGA) design-
certified for natural and propane gases (see furnace rating plate)
and for installation in alcoves, attics, basements, closets, utility
rooms, crawlspaces, and garages. This furnace is factory-shipped
REGISTERED QUALITY SYSTEM
Ca
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Cor porat
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IST
ERED F
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9001
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8
8
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®
EFFICIENCY
RATING
CERTIFIED
CERTIFIED
Fig. 1—Multipoise Orientations
A93041
UPFLOW
DOWNFLOW
HORIZONTAL
LEFT
AIRFLOW
AIRFLOW
AIRFLOW
AIRFLOW
HORIZONTAL
RIGHT
2
