DD-17DSI Furnace Manual

The DD-17DSI is a high-efficiency residential furnace with advanced digital controls, variable-speed blower motor, multi-stage heating capability, and energy-saving features. Designed for optimal performance in various climate conditions with safety shut-off systems, diagnostic LED indicators, and easy maintenance access. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Digital control board, variable-speed blower, heat exchanger, gas valve, pressure switches, flame sensor, and diagnostic LED.

Feature	Description
Digital control board	Microprocessor-based control for precise operation
Variable-speed blower	Adjustable airflow for efficiency and comfort
Multi-stage heating	Two-stage operation for energy savings
Diagnostic LED	Flashing codes for troubleshooting
Safety shut-off	Automatic shutdown for unsafe conditions
Pressure switches	Verify proper venting operation
Flame sensor	Detects burner flame presence
Gas valve	Regulates gas flow to burners
Filter access	Easy-to-reach filter compartment
Drain connections	Condensate removal system

Installation

Unpack and inspect all components. Ensure proper clearances and venting.

1. Position furnace: Place on stable, level surface with proper clearances.
2. Connect gas supply: Use approved gas piping and fittings.
3. Install venting: Follow manufacturer specifications for vent pipe installation.
4. Electrical connections: Connect to proper voltage supply and install disconnect switch.
5. Ductwork: Connect supply and return ducts securely.

WARNING! Installation must be performed by qualified HVAC technician. Gas connections require leak testing.

First-Time Setup

Power on furnace; follow startup sequence.

1. Verify gas supply: Ensure gas valve is open and supply is adequate.
2. Check electrical: Confirm proper voltage and grounding.
3. Set thermostat: Install compatible thermostat and configure settings.
4. Test operation: Initiate heating cycle and verify proper operation.
5. Adjust blower speed: Set according to duct system requirements.

CAUTION! Never bypass safety controls. Test carbon monoxide detectors after installation.

Specifications

• Heating Capacity: 60,000-100,000 BTU/h (model dependent)
• Efficiency: Up to 96% AFUE
• Stages: Two-stage heating operation
• Blower Motor: ECM variable-speed
• Voltage: 120V AC, 60Hz
• Gas Type: Natural gas (LP conversion kit available)
• Venting: PVC pipe required
• Dimensions: Varies by model
• Sound Level: Ultra-quiet operation
• Warranty: Limited lifetime heat exchanger

Controls and Settings

Access control board via front panel. LED indicators show system status.

Thermostat: Compatible with most 24V systems. Supports multi-stage operation.

Control Board: DIP switches for blower speed, heating stages, and timing. Diagnostic LED flashes error codes. Gas Valve: Regulates gas pressure and flow. Blower Control: Adjustable speeds for heating and continuous fan operation.

Connecting to HVAC System

Gas supply: 1/2" or 3/4" black iron pipe. Electrical: 120V dedicated circuit. Thermostat: 2-5 wire connection.

1. Turn off power and gas supply before connections.
2. Install gas line with sediment trap and shut-off valve.
3. Connect thermostat wires to control board terminals.
4. Verify proper venting and combustion air supply.

Tip: Use pipe sealant approved for gas applications. Pressure test all gas connections.

Operation Modes

Supports heating, fan-only, and diagnostic modes.

1. Heating mode: Two-stage operation for efficiency and comfort
2. Fan control: Auto or continuous operation
3. Diagnostic mode: LED flash codes for troubleshooting
4. Safety shutdown: Automatic protection systems
5. Standby mode: Low power consumption when not active

WARNING! Do not operate with access panels removed. Keep combustible materials away from furnace.

Maintenance Procedures

Regular maintenance ensures optimal performance and safety.

1. Monthly: Check and replace air filter as needed
2. Annual: Professional inspection and cleaning
3. Seasonal: Verify proper venting and drain operation
4. As needed: Clean flame sensor and burners

CAUTION! Always turn off power and gas before servicing. Use only manufacturer-approved parts.

Safety Features

Multiple safety systems protect against hazardous conditions.

• Flame rollout switches
• High limit switches
• Pressure switches
• Flame sensor
• Ignition control lockout
• Condensate overflow switch

Regulatory Information

UL certified for safety standards. ANSI Z21.47 compliant for gas appliances. Meets DOE efficiency requirements. Installation must comply with local building codes and NFPA 54. For technical support, contact manufacturer at 1-800-555-HEAT or visit www.ddfurnace.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, safety lockout	Check power supply; verify thermostat setting; reset disconnect switch.
No heat	Gas supply, igniter, flame sensor	Verify gas valve open; check igniter operation; clean flame sensor.
Blower not working	Motor, capacitor, control board	Check motor operation; test capacitor; verify control board signals.
Frequent cycling	Filter, thermostat, limit switch	Replace dirty filter; check thermostat location; test limit switch.
Error codes flashing	Various system faults	Refer to diagnostic chart in manual; count LED flashes.

Reset: Turn power off for 30 seconds then restore.

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