Concord 90 Plus Gas Furnace Manual

The Concord 90 Plus is a high-efficiency gas furnace with AFUE rating of 90% or higher, featuring electronic ignition, variable-speed blower motor, multi-speed operation, sealed combustion system, diagnostic LED indicator, built-in condensate removal system, and compatibility with standard thermostat controls. Designed for residential use with natural gas or propane capability. Below are key sections for safety, features, installation, setup, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation Requirements 3. Initial Setup & Startup 4. Technical Specifications 5. Controls and Operation 6. Thermostat Connection 7. Maintenance Procedures 8. Safety Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Heat exchanger, blower assembly, gas valve, ignition system, pressure switches, flame sensor, condensate system, control board.

Feature	Description
AFUE Rating	90% or higher efficiency rating
Blower Motor	Variable-speed ECM motor for quiet operation
Ignition System	Hot surface ignition for reliable startup
Combustion System	Sealed combustion for safety and efficiency
Diagnostic LED	Flashing code indicator for troubleshooting
Gas Valve	Modulating valve for precise temperature control
Pressure Switches	Safety switches for combustion air verification
Flame Sensor	Monitors burner flame presence
Condensate System	Removes condensation from high-efficiency operation
Filter System	Standard 1-inch or 4-inch media filter capability

Installation Requirements

Professional installation required. Verify local codes and obtain permits.

Location: Install in approved area with proper clearances and combustion air.
Venting: Use approved PVC pipe for concentric or two-pipe system.
Gas Supply: Proper gas line sizing with sediment trap and shutoff valve.
Electrical: 120V AC power supply with proper grounding.
Drainage: Condensate drain line to approved disposal point.

WARNING! Gas furnaces produce carbon monoxide; proper installation and venting critical for safety. Only qualified technicians should install.

Initial Setup & Startup

Professional startup procedure required for proper operation.

Verify installation: Check all connections, clearances, and venting.
Gas pressure: Set manifold pressure per specifications (3.5" WC natural gas).
Electrical: Verify proper voltage and grounding.
Startup sequence: Power on, verify blower operation, check ignition sequence.
Temperature rise: Measure and adjust blower speed for proper temperature rise.
Combustion analysis: Verify proper CO levels and efficiency.

CAUTION! Never bypass safety controls. Always verify proper operation before leaving installation.

Technical Specifications

AFUE Rating: 90%+
Input BTU/H: 40,000 - 120,000 (varies by model)
Output BTU/H: 36,000 - 108,000 (varies by model)
Gas Type: Natural gas or propane (conversion kit required)
Electrical: 120V AC, 60Hz, 5-8 amps
Blower Motor: Variable-speed ECM
Static Pressure: 0.1" to 0.8" WC maximum
Temperature Rise: 35°F to 65°F
Venting: 2" PVC pipe minimum
Sound Level: < 65 dBA

Controls and Operation

Integrated control board manages all furnace functions with diagnostic capabilities.

Control Board: LED status light, dip switches for configuration, terminal strip for thermostat connection.

Operation Modes: Heating mode, fan continuous mode, diagnostic mode. Settings: Blower speed adjustments, timing delays, fault code reset. Safety Controls: Limit switches, pressure switches, flame rollout switches, ignitor control.

Thermostat Connection

Compatible with standard 24V thermostats. Connection terminal designations: R, C, W, G, Y.

Turn off power to furnace before connecting thermostat.
Connect thermostat wires to control board terminal strip.
Verify proper operation: Heat call, fan operation, system cycling.
Program thermostat for desired temperature settings and schedules.

Tip: Use programmable thermostat for maximum efficiency and comfort.

Maintenance Procedures

Regular maintenance required for optimal performance and safety.

Monthly: Check and replace air filter as needed.
Annual: Professional inspection and cleaning recommended.
Burner inspection: Clean burners and verify proper flame pattern.
Heat exchanger: Visual inspection for cracks or damage.
Blower assembly: Clean blower wheel and housing.
Condensate system: Flush and clean condensate trap and drain lines.
Electrical: Check all connections and component operation.
Venting: Inspect vent pipes for obstructions or damage.

WARNING! Always turn off gas and electrical power before performing any maintenance.

Safety Features

Multiple safety systems protect against hazardous conditions: Flame rollout switches, high limit switches, pressure switches, ignitor safety lockout, condensate overflow switch.

Care & Cleaning

Keep furnace area clean and clear of combustible materials. Regular filter changes essential.

CAUTION! Never store chemicals or flammable materials near furnace. Keep intake and exhaust vents clear of obstructions.

Regulatory Information

ANSI Z21.47/CSA 2.3 certified. UL listed. Meets DOE efficiency standards. Manufactured to comply with U.S. safety and efficiency regulations. For technical support, contact Concord HVAC at 1-800-555-HEAT or visit www.concordhvac.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, safety lockout	Check power switch; verify thermostat setting; check diagnostic LED for fault code.
No heat	Gas supply, ignition, limit switch	Verify gas valve on; check for ignition attempts; reset limit switch if tripped.
Blower won't run	Motor, capacitor, control board	Check for power to blower; inspect capacitor; verify control board operation.
Frequent cycling	Filter, thermostat, limit switch	Replace dirty filter; check thermostat location; verify proper airflow.
Error codes flashing	Various fault conditions	Count LED flashes and refer to fault code chart in service manual.

Reset: Power cycle furnace to clear temporary fault conditions.

Service: 1-800-555-HEAT; www.concordhvac.com