Carrier Weathermaker 8000 Furnace Service Manual

The Carrier Weathermaker 8000 is a high-efficiency gas furnace designed for residential heating applications. This model features advanced combustion technology, variable-speed blower motor, electronic ignition system, and comprehensive safety controls. Below are key sections for safety procedures, technical specifications, installation guidelines, maintenance procedures, troubleshooting, and service protocols.

Features at a Glance

Key components: Stainless steel heat exchanger, variable-speed ECM blower motor, hot surface ignitor, pressure switches, flame sensor, and integrated control board.

Installation Guidelines

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

1. Location selection: Install in clean, dry area with adequate combustion air and service clearance.
2. Venting: Install PVC vent pipes according to manufacturer specifications with proper slope.
3. Gas connection: Use approved pipe dope and leak test all connections.
4. Electrical: Connect to dedicated 120V circuit with proper grounding.
5. Drain lines: Install condensate drain with proper trap and routing.

WARNING! Gas furnaces produce carbon monoxide. Proper venting is essential for safety. Always verify gas type matches furnace rating plate.

Initial Setup & Commissioning

Complete proper startup procedure to ensure optimal performance and safety.

1. Verify installation: Check all connections, clearances, and venting.
2. Gas pressure: Set manifold pressure to specifications (typically 3.5" WC for natural gas).
3. Combustion analysis: Verify CO levels and combustion efficiency.
4. Blower settings: Adjust dip switches for proper airflow and temperature rise.
5. System operation: Test complete heating cycle and safety controls.

CAUTION! Only qualified technicians should perform startup procedures. Document all measurements and settings.

Technical Specifications

• Input Capacity: 60,000 - 120,000 BTU/H (model dependent)
• AFUE Rating: Up to 96% efficiency
• Gas Type: Natural gas or LP (conversion kit required)
• Electrical: 120V AC, 60Hz, 15 amp circuit
• Static Pressure: 0.1" - 0.8" WC maximum
• Temperature Rise: 35°F - 65°F (adjustable)
• Blower Speeds: Multiple speed taps for heating and cooling
• Venting: 2" - 3" PVC depending on length and fittings
• Sound Rating: Ultra-quiet operation
• Dimensions: Varies by model (check specific model data)

Control System Overview

The integrated control board manages all furnace operations with comprehensive diagnostics.

Control Board Features: LED status indicator, dip switch settings, terminal connections for thermostat, pressure switch inputs, gas valve control, ignitor control, blower motor control.

Operation Sequence: Call for heat → Inducer motor on → Pressure switch prove → Hot surface ignitor on → Gas valve open → Flame sense → Main blower on → Satisfy thermostat → Shutdown sequence.

Diagnostic Codes: Flash codes indicate specific faults (1 flash = pressure switch, 2 flashes = ignition failure, etc.)

Electrical Connections

Proper electrical connections ensure reliable operation and safety.

1. Disconnect power before servicing any electrical components.
2. Verify line voltage: 120V ±10% at furnace connections.
3. Thermostat connections: R, W, G, C, Y terminals as required.
4. Grounding: Ensure proper equipment grounding.
5. Low voltage: Check transformer output and fuse integrity.

Tip: Use voltage tester to verify power is off before working on electrical components.

Gas System Operation

The gas system delivers precise fuel control for efficient combustion.

1. Gas valve operation: Modulating valve adjusts gas flow based on demand.
2. Manifold pressure: Verify and adjust to manufacturer specifications.
3. Combustion air: Ensure adequate air supply for proper combustion.
4. Venting: Check vent pipe integrity and proper termination.
5. Flame characteristics: Blue flame with slight orange tips indicates proper combustion.
6. Gas leak check: Use approved leak detection solution on all connections.
7. CO levels: Measure flue gas CO levels during operation.
8. Pressure switches: Verify proper operation and settings.

WARNING! Gas leaks can cause explosion or fire. Always leak test after any gas work. Carbon monoxide poisoning can be fatal.

Maintenance Procedures

Regular maintenance ensures longevity and efficiency.

Annual Maintenance Checklist: Replace air filter, clean burners, inspect heat exchanger, check flame sensor, clean condensate system, verify gas pressure, check electrical connections, test safety controls, measure temperature rise, verify venting integrity.

Safety Information

Critical safety procedures must be followed during all service work.

CAUTION! Always disconnect power and gas supply before servicing. Use carbon monoxide detector when testing. Follow lockout/tagout procedures. Wear appropriate PPE.

Regulatory Information

UL certified for safety. ANSI Z21.47 standards compliance. Meets DOE efficiency requirements. Local codes may have additional requirements. Copyright © Carrier Corporation. All rights reserved. For technical support, contact Carrier at 1-800-CARRIER or visit www.carrier.com.

Troubleshooting Guide

Reset Procedure: Turn power off for 30 seconds, then restore power to reset control board.

Service Support: 1-800-CARRIER; www.carrier.com