Carrier Furnace 58MCB Manual

The Carrier 58MCB is a high-efficiency gas furnace series with AFUE ratings up to 96%, multi-speed blower motor, durable heat exchanger, electronic ignition, variable-speed operation, and compatibility with various thermostat systems. Available in multiple sizes from 40,000 to 150,000 BTU/hr. Below are key sections for safety, features, installation, setup, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Thermostat 7. Operation 8. Maintenance 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Heat exchanger, blower assembly, gas valve, ignition system, pressure switches, limit controls, filter rack.

Feature	Description
Heat Exchanger	Durable stainless steel construction
Blower Motor	Multi-speed ECM motor for efficient operation
Ignition System	Hot surface electronic ignition
Gas Valve	Modulating/Two-stage gas control
Pressure Switches	Safety verification of vent operation
Limit Controls	High temperature safety shutoff
Filter Rack	Standard 1-inch or 4-inch media filter compatible
Control Board	Integrated furnace controller with LED status lights
Vent System	PVC venting compatible
Drain System	Condensate removal with safety switch

Installation

Unpack and inspect contents. Ensure proper location with adequate clearance.

Position furnace: Level, stable surface with proper clearances (minimum 1 inch sides, 6 inches front).
Connect gas supply: Use black iron pipe with proper thread sealant.
Connect electrical: 120V AC power supply with proper grounding.
Connect venting: PVC pipe system for intake and exhaust.
Connect thermostat: Low voltage wiring to control board.
Connect ductwork: Properly sized supply and return ducts.

WARNING! Gas appliances require professional installation. Follow all local codes. Ensure proper ventilation.

First-Time Setup

Power on furnace; verify proper operation.

Check gas connections: Use leak detection solution on all joints.
Verify electrical: Proper voltage at control board.
Set thermostat: Install batteries, configure heating mode.
Test operation: Set thermostat above room temperature to initiate heating cycle.
Check airflow: Verify proper airflow from all registers.
Monitor ignition: Observe proper ignition sequence.

CAUTION! Never bypass safety controls. Ensure proper combustion air supply.

Specifications

Model Series: 58MCB
AFUE Rating: Up to 96%
Heating Capacity: 40,000 - 150,000 BTU/hr
Stages: Single-stage, Two-stage, or Modulating
Blower Type: Multi-speed ECM
Electrical: 115V/60Hz/1PH
Gas Type: Natural Gas (LP conversion kit available)
Venting: PVC, CPVC, or ABS
Sound Level: As low as 65 dBA
Dimensions: Varies by model (typical 21"W x 21"D x 45"H)

Controls and Settings

Access control board via front panel. LED status lights indicate system operation.

Control Board: POWER switch, Fuse, LED status indicators, DIP switches for configuration.

Settings: Blower speed adjustments, heating cycle timing, thermostat compatibility settings. DIP switch settings for staging, fan control, accessory configuration. LED flash codes for diagnostics (1 flash = normal, 2 flashes = pressure switch, etc.).

Connecting Thermostat

Standard 5-wire thermostat connection (R, W, Y, G, C).

Turn off power to furnace before wiring.
Connect thermostat wires to control board terminals.
Match wire colors: R (24V), W (Heat), Y (Cool), G (Fan), C (Common).
Configure thermostat for proper system type (gas furnace).

Tip: Use thermostat compatible with furnace staging (single-stage, two-stage, or modulating).

Operation

Heating cycle sequence: Thermostat call, inducer motor start, pressure switch verification, hot surface ignition, gas valve opening, flame verification, blower activation.

Set thermostat to desired temperature.
Furnace initiates heating cycle when room temperature drops below set point.
Observe proper ignition sequence (inducer motor, ignition, flame).
Blower activates after heat exchanger warm-up period.
Cycle completes when thermostat satisfied.

WARNING! Never operate without filter. Ensure proper ventilation during operation.

Maintenance

Regular maintenance ensures optimal performance and safety.

Monthly: Check and replace air filter as needed.
Seasonal: Inspect vent system for obstructions.
Annual: Professional inspection of heat exchanger, burners, gas valve.
Annual: Clean blower assembly and check motor operation.
Annual: Verify safety controls and limit switches.

Care & Cleaning

Turn off power before cleaning. Use soft brush and vacuum for dust removal.

CAUTION! Do not use water or liquid cleaners. Keep electrical components dry. Never bypass safety devices.

Regulatory Information

UL certified. ANSI Z21.47 compliant. Meets DOE energy efficiency standards. Manufactured to comply with U.S. safety and performance standards. For support, visit www.carrier.com or contact 1-800-CARRIER. Installation must comply with local building codes and NFPA 54.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, switch	Check power supply, thermostat settings, door switch
No heat	Gas supply, ignition	Verify gas valve on, check for ignition failure
Short cycling	Filter, limit switch	Replace dirty filter, check high limit switch
Blower won't stop	Thermostat, control board	Check thermostat fan setting, control board operation
Unusual noises	Blower, inducer motor	Inspect blower wheel, inducer motor bearings
LED error codes	Various faults	Refer to control board LED flash code chart

Reset: Turn power off for 30 seconds, then restore.

Service: 1-800-CARRIER; www.carrier.com