Day & Night Plus 80 Furnace Manual

The Day & Night Plus 80 Furnace is a high-efficiency gas furnace designed for residential heating applications. With an 80% AFUE rating, this furnace provides reliable and efficient heating performance. Features include electronic ignition, multi-speed blower motor, safety controls, and compatibility with standard thermostat systems. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Heat exchanger, blower assembly, gas valve, electronic ignition system, pressure switches, limit controls, and venting system.

Installation Requirements

Proper installation is critical for safe and efficient operation. Follow all local codes and manufacturer instructions.

1. Location: Install in dry, clean area with adequate combustion air and service clearance.
2. Venting: Use approved Category I vent materials; maintain proper slope and clearances.
3. Gas Supply: Connect to proper gas type (natural gas or propane); use approved piping materials.
4. Electrical: Connect to 120V AC power; proper grounding required.
5. Ductwork: Ensure proper sizing and sealing of supply and return ducts.

WARNING! Installation must be performed by qualified HVAC technician. Improper installation can cause fire, explosion, or carbon monoxide poisoning.

First-Time Setup

Initial startup and commissioning procedures.

1. Verify installation: Check all connections, clearances, and venting.
2. Gas pressure: Set manifold pressure to specifications (3.5" WC natural gas).
3. Electrical: Verify proper voltage and grounding.
4. Startup sequence: Follow lighting instructions on unit label.
5. System check: Verify proper ignition, flame sensing, and safety controls.
6. Airflow: Set blower speeds for proper temperature rise.

CAUTION! Only qualified service personnel should perform initial startup and adjustment.

Specifications

• Model Series: Plus 80
• AFUE: 80%
• Input BTU/H: 40,000 - 120,000 (varies by model)
• Output BTU/H: 32,000 - 96,000 (varies by model)
• Gas Type: Natural gas or propane (conversion kit required)
• Electrical: 120V AC, 60Hz
• Blower Motor: Multi-speed PSC
• Venting: Category I, 4-5 inch diameter
• Temperature Rise: 35-65°F
• Sound Level: < 65 dBA

Controls and Settings

Integrated control board manages all furnace operations with LED status indicators.

Control Board Features: Self-diagnostic capability, status LED, safety lockout, blower control, ignition sequence.

Thermostat Connections: R (24V), W (Heat), G (Fan), C (Common). Blower Speeds: Adjustable for heating and continuous fan operation. Limit Switches: Automatic high-temperature protection. Pressure Switches: Verify proper venting operation. Gas Valve: Regulates gas flow with manual shutoff.

Venting and Ductwork

Proper venting is essential for safe operation and efficiency.

1. Vent Type: Category I - negative pressure, natural draft
2. Vent Material: Type B vent pipe or approved equivalent
3. Clearances: Maintain required clearances to combustibles
4. Termination: Proper height above roof and away from windows
5. Duct Sizing: Follow Manual D calculations for proper airflow
6. Filter: Use correct size and MERV rating for system

Tip: Regular inspection of vent system prevents blockage and ensures proper draft.

Operation Instructions

Normal operating sequence and user controls.

1. Thermostat Call: Set thermostat above room temperature for heat.
2. Inducer Operation: Blower starts to prove draft.
3. Ignition Sequence: Hot surface igniter glows, gas valve opens.
4. Flame Sensing: Control board verifies flame presence.
5. Blower Operation: Blower starts after heat exchanger warms.
6. Shutdown: Gas valve closes when thermostat satisfied, blower continues for cool-down.

WARNING! Never adjust gas pressure or safety controls unless qualified. Contact professional service for adjustments.

Maintenance Procedures

Regular maintenance ensures efficiency and longevity.

1. Monthly: Check and replace air filter as needed.
2. Annual: Professional inspection and cleaning.
3. Burner Inspection: Clean burners and heat exchanger.
4. Vent System: Inspect for blockage or deterioration.
5. Electrical: Check connections and component operation.
6. Gas Connections: Leak test at gas valve and manifold.

CAUTION! Turn off gas and electrical power before performing any maintenance.

Safety Information

Critical safety warnings and precautions.

• Install carbon monoxide detectors in living areas
• Never block return or supply air vents
• Keep combustible materials away from furnace
• Ensure adequate combustion air supply
• Regular professional inspection recommended
• Immediately shut off if gas odor detected

EMERGENCY: If you smell gas, immediately evacuate and call gas company from outside.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified to national standards for gas-fired central furnaces. UL listed for electrical safety. Meets DOE energy efficiency standards. Manufactured to comply with applicable safety and performance requirements. For technical support, contact Day & Night at 1-800-722-2100 or visit www.daynight.com.

Troubleshooting

Reset: Power cycle furnace by turning off power for 30 seconds, then restore.

Service: 1-800-722-2100; www.daynight.com