ML195 Gas Furnace Manual

The ML195 Gas Furnace is a high-efficiency residential heating system with AFUE rating up to 95%, variable-speed blower motor, two-stage gas valve operation, electronic ignition system, durable heat exchanger, integrated diagnostic controls, safety shutoff features, and compatibility with standard thermostat systems. Designed for reliable performance in residential applications with proper installation and maintenance. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Two-stage gas valve, variable-speed blower, electronic ignition, heat exchanger, pressure switches, flame sensor, diagnostic LED, filter access panel.

Installation Requirements

Professional installation required. Verify local codes and obtain permits.

1. Location: Install in approved area with proper clearances and combustion air.
2. Venting: Use approved PVC vent pipe for high-efficiency operation.
3. Gas connection: Use black iron pipe with proper sizing and leak testing.
4. Electrical: 120V AC power supply with proper grounding.
5. Drain line: Install condensate drain with proper routing and trap.

WARNING! Gas furnaces produce carbon monoxide; proper venting is critical. Installation must comply with all local codes.

Initial Setup & Startup

Professional startup procedure required for safety and warranty.

1. Verify installation: Check all connections, clearances, and venting.
2. Gas pressure: Adjust manifold pressure per specifications.
3. Electrical: Connect thermostat and verify proper wiring.
4. Startup sequence: Follow manufacturer's startup checklist.
5. System check: Verify proper ignition, heating operation, and safety controls.

CAUTION! Only qualified technicians should perform startup procedures. Carbon monoxide poisoning hazard exists if improperly installed.

Technical Specifications

• AFUE Rating: Up to 95% efficiency
• Input Capacity: 40,000 to 120,000 BTU/H (multiple models)
• Gas Type: Natural gas (LP conversion kit available)
• Electrical: 120V AC, 60Hz, 5-8 amps
• Blower Motor: Variable-speed ECM
• Stages: Two-stage heating operation
• Venting: PVC pipe (2" or 3" diameter)
• Sound Level: Less than 70 dBA
• Dimensions: Varies by model (typical: 21"W x 21"D x 40"H)
• Warranty: Limited lifetime heat exchanger, 10 years parts

Controls and Operation

Integrated control board manages all furnace operations with diagnostic capabilities.

Control Board: Monitors safety devices, controls ignition sequence, manages blower operation, displays error codes via LED.

Operation Modes: Heating cycle, blower delay, continuous fan, diagnostic mode. Settings: Blower speed adjustments, temperature rise verification, dip switch settings for capacity and blower operation. Diagnostics: LED flash codes indicate specific faults for troubleshooting.

Thermostat Connection

Compatible with standard 24V thermostat systems.

1. Turn off power to furnace before wiring.
2. Connect thermostat wires to control board: R (power), W (heat), G (fan), C (common).
3. Verify proper thermostat operation and system response.
4. For advanced thermostats, follow manufacturer's installation instructions.

Tip: Use programmable thermostat for optimal efficiency and comfort.

Maintenance Procedures

Regular maintenance ensures efficiency, safety, and longevity.

1. Monthly: Check and replace air filter as needed.
2. Annual: Professional inspection and cleaning recommended.
3. Burner inspection: Clean and verify proper flame pattern.
4. Heat exchanger: Visual inspection for cracks or damage.
5. Blower assembly: Clean blower wheel and housing.
6. Drain system: Clean condensate trap and drain lines.
7. Safety devices: Test pressure switches, limit controls, flame sensor.

WARNING! Turn off gas and electrical power before performing any maintenance. Only qualified technicians should service gas components.

Safety Features

Multiple safety systems protect against hazardous conditions.

Flame Rollout Switches: Detect improper burner combustion. Limit Switches: Prevent overheating. Pressure Switches: Verify proper venting operation. Ignition Control: Safe start-up sequence with trial for ignition. Gas Valve: Automatic shutoff if unsafe conditions detected.

Care & Cleaning

Regular cleaning maintains efficiency and prevents issues.

Air Filter: Replace every 1-3 months depending on usage. External Surfaces: Wipe with damp cloth only. Vent Pipes: Keep clear of obstructions. Drain Lines: Flush annually to prevent clogging. Burners: Professional cleaning only.

CAUTION! Do not use water or cleaning solutions on electrical components. Keep combustion air intake clear.

Regulatory Information

UL certified for safety standards. ANSI Z21.47 compliant for gas appliances. CSA certified for Canadian standards. Installation must comply with National Fuel Gas Code NFPA 54/ANSI Z223.1 and local building codes. For support, contact manufacturer technical service or authorized dealers.

Troubleshooting

Reset: Turn power off for 30 seconds, then restore. Check diagnostic LED for codes.

Service: Contact qualified HVAC technician for all gas and electrical repairs.