Day and Night Furnace Repair Manual

The Day and Night furnace is a high-efficiency heating system designed for residential and light commercial applications. This manual covers gas-fired forced air furnaces with AFUE ratings up to 96%, featuring electronic ignition, multi-speed blowers, safety controls, and compatibility with various thermostat systems. Below are key sections for safety procedures, technical specifications, installation guidelines, troubleshooting, maintenance, and repair instructions.

1. Safety Precautions 2. Model Identification 3. Technical Specifications 4. Installation Requirements 5. Electrical Connections 6. Gas Line Connections 7. Venting Systems 8. Startup and Commissioning 9. Operating Instructions 10. Maintenance Procedures 11. Troubleshooting Guide

Safety Precautions

Critical safety information for furnace installation, operation, and maintenance.

Hazard	Precaution
Gas leaks	Check all connections with leak detection solution; never use open flame
Carbon monoxide	Ensure proper venting; install CO detectors in living areas
Electrical shock	Disconnect power before servicing; use lockout/tagout procedures
Hot surfaces	Allow furnace to cool before handling internal components
Combustible materials	Maintain clearances per installation instructions

Model Identification

Locate model and serial numbers for proper parts identification and technical support.

Model number: Found on rating plate inside furnace cabinet
Serial number: Located adjacent to model number
Manufacturing date: Encoded in serial number (first four digits)
Technical specifications: Refer to model number for capacity and features

WARNING! Always provide complete model and serial numbers when ordering parts or seeking technical assistance.

Technical Specifications

Input Capacity: 40,000 to 120,000 BTU/hr
AFUE Rating: 80% to 96% efficiency
Gas Type: Natural gas or propane (field convertible)
Gas Pressure: Natural gas: 3.5" WC; Propane: 10" WC
Electrical: 120V AC, 60Hz, 15 amp circuit
Blower Motor: Multi-speed ECM or PSC
Ignition System: Hot surface or intermittent pilot
Venting: Category I or IV depending on model
Dimensions: Varies by model (check specific model data)

Installation Requirements

Proper installation is critical for safe and efficient operation.

Location: Install in areas with adequate combustion air and service access
Clearances: Maintain minimum clearances to combustible materials
Combustion air: Provide adequate fresh air per local codes
Drain lines: Install condensate drain per instructions for high-efficiency models
Venting: Install vent system according to furnace category and local codes

CAUTION! Installation must comply with all local codes and manufacturer specifications.

Electrical Connections

Wiring requirements and connection procedures.

Connection	Specification
Line voltage	120V AC, 15 amp dedicated circuit
Thermostat	24V AC; R, W, G, Y, C terminals
Blower speeds	Cooling, heating, continuous fan settings
Safety controls	Limit switches, pressure switches, rollout switches
Control board	Integrated furnace controller with LED status lights

Gas Line Connections

Gas piping and connection requirements.

Pipe sizing: Size gas line per local codes and furnace input requirements
Shutoff valve: Install manual gas shutoff valve within 6 feet of furnace
Drip leg: Install sediment trap ahead of gas control valve
Pressure test: Test gas lines at maximum operating pressure
Leak check: Test all connections with approved leak detection solution

WARNING! Gas connections must be made by qualified personnel only.

Venting Systems

Venting requirements based on furnace category.

Category I: Natural draft; metal vent pipe
Category IV: Direct vent or sealed combustion; PVC/CPVC pipe
Vent sizing: Follow manufacturer specifications for pipe diameter
Termination: Maintain proper clearances from windows and openings
Slope: Horizontal runs must slope back toward furnace

Startup and Commissioning

Initial startup procedures and system verification.

Verify all connections: Electrical, gas, venting, drain
Check gas pressure: Manifold and inlet pressures
Test safety controls: Verify proper operation of all safety devices
Measure temperature rise: Ensure within specified range
Check combustion: Use combustion analyzer for high-efficiency models
Program thermostat: Set heating cycles and fan operation

NOTE: Complete startup checklist and leave with homeowner.

Operating Instructions

Normal operation and user controls.

Control	Function
Thermostat	Set desired temperature; system auto-cycles
System switch	Heat, Off, Cool (if AC equipped)
Fan switch	Auto or On for continuous circulation
LED status lights	Flash codes indicate system status
Reset buttons	Manual reset for rollout or limit switches

Maintenance Procedures

Routine maintenance for optimal performance and longevity.

Monthly: Check air filter; replace when dirty
Seasonal: Inspect burners, heat exchanger, vent system
Annual: Clean blower assembly and combustion chamber
Biannual: Check gas pressure and combustion analysis
As needed: Lubricate blower motor (if required)

CAUTION! Disconnect power and gas before performing maintenance.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No heat	Thermostat, power, gas valve	Check thermostat setting; verify power; check gas valve operation
Blower won't run	Motor, capacitor, control board	Test motor windings; check capacitor; verify control signal
Short cycling	Dirty filter, limit switch	Replace filter; check limit switch operation; verify airflow
Ignition failure	Igniter, flame sensor, gas pressure	Test igniter continuity; clean flame sensor; check gas pressure
Unusual noises	Blower wheel, inducer motor	Inspect for debris; check motor bearings; tighten components
Error codes	Control board diagnostics	Interpret LED flash codes; refer to diagnostic chart

Technical Support: 1-800-DAY-NIGHT; www.dayandnightfurnace.com

Emergency Service: Contact qualified HVAC technician for gas or electrical issues