Carrier Infinity 98 Gas Furnace Installation Manual

The Carrier Infinity 98 Gas Furnace is a high-efficiency residential heating system with up to 98.5% AFUE rating, variable-speed blower motor, two-stage gas valve operation, advanced diagnostic controls, and compatibility with Carrier's Infinity System control. This manual covers safety precautions, installation procedures, startup instructions, wiring diagrams, and maintenance guidelines for professional HVAC technicians.

1. Safety Precautions 2. Unit Specifications 3. Pre-Installation Requirements 4. Installation Procedures 5. Electrical Wiring 6. Gas Piping Connections 7. Venting System 8. Startup and Commissioning 9. Control System Setup 10. Maintenance Procedures 11. Troubleshooting Guide

Safety Precautions

Critical safety information for installation and service personnel.

Hazard	Precaution
Gas Leaks	Check all connections with leak detection solution before startup
Electrical Shock	Disconnect power before servicing; follow NEC guidelines
Carbon Monoxide	Ensure proper venting; test for CO after installation
Combustion Air	Provide adequate combustion and ventilation air per code
High Temperature	Allow unit to cool before handling heat exchanger components

Unit Specifications

Model Series: 59MN
AFUE Rating: Up to 98.5%
Input Capacity: 40,000 to 120,000 BTU/hr
Stages: Two-stage gas valve operation
Blower Type: Variable-speed ECM motor
Voltage: 120V AC, 60Hz
Venting: PVC/CPVC Category IV venting
Gas Type: Natural gas (convertible to LP)
Dimensions: Varies by model - consult unit data plate

Pre-Installation Requirements

Site preparation and verification before installation.

Verify unit size matches heat load calculation
Check local codes for compliance requirements
Ensure adequate clearances: 1" sides, 6" vent, 24" front
Confirm adequate combustion air supply
Inspect existing gas line for proper size and pressure

WARNING! Installation by qualified HVAC technician required. Improper installation may create hazardous conditions.

Installation Procedures

Step-by-step installation guidelines.

Position furnace: Level unit on solid, stable base
Connect return air: Secure ductwork to return air opening
Connect supply air: Attach supply ductwork to plenum
Install filter rack: Position for easy filter access
Secure unit: Fasten to floor or platform as required

CAUTION! Unit is heavy; use proper lifting equipment and techniques.

Electrical Wiring

Electrical connections and requirements.

Connection	Specification
Line Voltage	120V AC, 15 amp circuit minimum
Low Voltage	24V AC thermostat circuit
Blower Motor	ECM variable-speed with proprietary control
Grounding	Must be properly grounded per NEC
Control Board	Integrated Infinity control system

Gas Piping Connections

Gas supply requirements and connection procedures.

Shut off gas supply at main valve
Install sediment trap in gas line
Use approved pipe thread compound or tape
Connect gas line to unit gas valve
Pressure test: 14" WC natural gas, 11-14" WC LP

WARNING! Gas piping must be sized according to length and BTU load. Consult local codes.

Venting System

Category IV venting requirements and installation.

Vent Material: PVC, CPVC, or ABS approved for Category IV
Vent Size: 2" or 3" diameter depending on unit size and length
Slope: 1/4" per foot back toward furnace
Termination: Follow manufacturer clearance requirements
Combustion Air: Separate intake or direct vent configuration

Startup and Commissioning

Initial startup procedure and system verification.

Verify all connections are secure and proper
Open gas supply valve slowly
Power on furnace at electrical disconnect
Set thermostat to call for heat
Observe ignition sequence and flame
Measure temperature rise (35-65°F range)
Check gas pressure: 3.5" WC natural gas
Verify proper vent operation

Control System Setup

Infinity control system configuration.

Infinity Controller: Compatible with Carrier Infinity thermostats for advanced zoning, humidity control, and system monitoring.

Configuration: Access service menu for blower settings, staging parameters, and system optimization. Default settings optimized for most installations.

Maintenance Procedures

Routine maintenance requirements.

Monthly: Check air filter, replace as needed
Annual: Professional inspection and cleaning
Components: Inspect heat exchanger, burners, vent system
Blower: Clean blower wheel and housing annually
Drainage: Clear condensate trap and drain line

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No heat	Power, thermostat, pressure switch	Check power supply; verify thermostat setting; inspect pressure switch tubing
Short cycling	Dirty filter, high limit	Replace filter; check airflow; verify proper temperature rise
Blower not operating	Motor, control board, wiring	Check motor connections; test control board outputs; verify blower settings
Lockout condition	Ignition failure, flame sense	Check gas supply; clean flame sensor; verify proper grounding
Error codes displayed	System faults	Refer to control board LED codes; consult service manual

Service: Contact Carrier authorized dealer for technical support. Warranty registration required within 60 days of installation.