Suburban Furnace Installation Manual

The Suburban Furnace is a high-efficiency heating system designed for residential and light commercial applications. This manual covers the SF-20 series with natural gas/LP gas compatibility, electronic ignition, variable speed blower, multi-position installation capability, built-in safety controls, diagnostic LED system, and energy efficiency ratings up to 95% AFUE. Below are key sections for safety, installation procedures, electrical connections, gas connections, startup, operation, maintenance, and troubleshooting.

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

Safety Precautions

Critical safety information for proper installation and operation.

Hazard Type	Precaution
Fire/Explosion	Install in well-ventilated area away from combustible materials
Carbon Monoxide	Ensure proper venting and annual inspection
Electrical Shock	Disconnect power before servicing
Gas Leaks	Use leak detection solution on all connections
Burns	Allow unit to cool before handling

WARNING! Installation must comply with local codes and NFPA 54/ANSI Z223.1.

Pre-Installation Requirements

Site preparation and necessary tools.

Location: Minimum clearances - 24" front, 6" sides, 12" top, 6" rear.
Combustion Air: Ensure adequate fresh air supply per local codes.
Floor Protection: Required for combustible flooring.
Tools Needed: Pipe wrenches, manifold gauge, voltmeter, leak detector.

CAUTION! Verify gas type (natural/LP) before installation.

Installation Procedures

Step-by-step installation guide.

Position unit: Level furnace on solid base or hanging brackets.
Duct connections: Secure supply and return ducts with approved tape/clamps.
Vent piping: Install according to manufacturer specifications.
Drain lines: Connect condensate drain to proper disposal.
Gas line: Install shutoff valve within 6 feet of unit.

WARNING! Use two people for lifting; unit weighs 85-120 lbs.

Electrical Connections

Wiring requirements and connections.

Power Supply: 120V AC, 60Hz, 15 amp circuit
Thermostat: 24V AC connection with conventional terminals
Grounding: Proper equipment grounding required
Blower Motor: ECM variable speed with dip switch settings
Control Board: Integrated diagnostic LED system

CAUTION! Disconnect power before making electrical connections.

Gas Connections

Gas line installation and pressure testing.

Pipe sizing: Minimum 1/2" black iron pipe for natural gas
Pressure test: Test at 14" WC for 10 minutes with no drop
Manifold pressure: Natural gas 3.5" WC, LP gas 10" WC
Leak check: Use soap solution on all connections
Sediment trap: Install at gas inlet as required by code

WARNING! Gas connections must be made by qualified technician.

Venting Requirements

Proper vent system installation.

Vent Type	Requirements
PVC	Schedule 40, minimum 2" diameter
CPVC	Approved for high-efficiency applications
Stainless Steel	AL29-4C for corrosive environments
Vent Length	Maximum 40 feet with two 90° elbows
Termination	12" minimum above grade, away from windows

Startup and Commissioning

Initial startup procedure and system verification.

Power on: Verify control board LED status
Gas valve: Open main gas shutoff valve slowly
Thermostat: Set to heat mode above room temperature
Sequence: Observe ignition sequence and flame establishment
Measurements: Verify gas pressure, temperature rise, CO levels

CAUTION! Never bypass safety controls during startup.

Operating Instructions

Normal operation and user controls.

Thermostat Settings: Programmable thermostat recommended for efficiency.

Operating Modes: Heat, Fan Only, Off. Blower delay adjustable 30-180 seconds.

Temperature Control: Maintain consistent temperature settings for optimal efficiency.

Fan Operation: Continuous fan mode available for air circulation.

Maintenance Schedule

Recommended maintenance intervals.

Monthly: Check air filter, clean if dirty
Annual: Professional inspection and cleaning
Every 2 Years: Heat exchanger inspection
As Needed: Blower wheel cleaning, drain line flushing
Seasonal: Check vent termination for obstructions

Tip: Keep maintenance records for warranty compliance.

Troubleshooting Guide

Common issues and solutions.

Symptom	Possible Cause	Corrective Action
No heat	Thermostat, power, gas supply	Check thermostat setting, circuit breaker, gas valve
Short cycling	Dirty filter, airflow restriction	Replace filter, check ductwork, verify temperature rise
Blower not running	Motor, capacitor, control board	Check voltage to motor, test capacitor, inspect control board
Lockout condition	Ignition failure, flame sensor	Reset power, clean flame sensor, check gas pressure
Unusual noises	Blower wheel, inducer motor	Inspect for debris, check motor bearings, tighten components

Technical Specifications

Model Series: SF-20 (40,000-120,000 BTU/hr)
Efficiency: 80-95% AFUE
Gas Types: Natural gas or LP (conversion kit required)
Electrical: 120V/1Ph/60Hz, 3-8 amps
Airflow: 800-2000 CFM variable speed
Sound Rating: < 75 dBA
Warranty: 20-year heat exchanger, 5-year parts
Dimensions: 21"W x 21"D x 45"H (typical)
Weight: 85-120 lbs depending on model

Service: 1-800-SUBURBAN; www.suburbanmanufacturing.com