Maratherm Gas Furnace Manual

The Maratherm Gas Furnace is a high-efficiency residential heating system designed for reliable performance and energy savings. This manual covers installation, operation, maintenance, and troubleshooting for various Maratherm furnace models. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Thermostat 7. Operating Instructions 8. Maintenance Procedures 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: High-efficiency heat exchanger, Electronic ignition system, Variable-speed blower motor, Multi-speed settings, Diagnostic LED lights, Safety shut-off valves.

Feature	Description
Heat Exchanger	Stainless steel construction for maximum efficiency and durability
Ignition System	Electronic hot surface ignition for reliable starts
Blower Motor	Variable-speed ECM motor for quiet operation and energy savings
Gas Valve	Modulating gas valve for precise temperature control
Air Filter	Standard 1-inch or 4-inch media filter options
Vent System	PVC venting for sidewall or roof termination
Control Board	Microprocessor-based for advanced diagnostics
Safety Features	Flame rollout switch, pressure switch, limit switches
Thermostat Compatibility	Works with standard 24V and smart thermostats
Warranty	Limited lifetime heat exchanger warranty

Installation

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

Position furnace: Place on stable, level surface in approved location with proper clearances.
Connect gas line: Use approved black iron pipe with proper thread sealant.
Install venting: Use PVC pipe according to local codes and manufacturer specifications.
Electrical connections: Connect 120V power supply and thermostat wiring.
Ductwork: Connect supply and return ducts securely.

WARNING! Gas furnaces must be installed by qualified HVAC technicians only. Improper installation can cause fire, explosion, or carbon monoxide poisoning.

First-Time Setup

Complete installation verification and initial startup procedure.

Gas pressure check: Verify inlet and manifold gas pressures are within specifications.
Vent system test: Check for proper draft and secure connections.
Electrical verification: Confirm proper voltage and grounding.
Initial startup: Follow lighting instructions; observe first ignition cycle.
System check: Verify proper airflow, temperature rise, and thermostat operation.

CAUTION! Always perform combustion analysis and carbon monoxide testing after installation.

Specifications

Input Capacity: 40,000 - 120,000 BTU/hr depending on model
AFUE Rating: 95%+ efficiency
Gas Type: Natural gas or propane (conversion kit required)
Electrical: 120V, 60Hz, 15 Amp circuit
Blower Motor: ECM variable speed, multi-tap settings
Static Pressure: 0.1 - 0.8 inches water column
Temperature Rise: 35°F - 65°F
Vent Size: 2" or 3" PVC depending on model
Sound Level: As low as 65 dB on low stage
Dimensions: Varies by model (typically 21"W x 21"D x 40"H)

Controls and Settings

Access control board via front panel. Diagnostic lights indicate system status.

Control Board: POWER switch, Diagnostic LED, DIP switch settings, Service test mode.

Blower Settings: CFM adjustments via DIP switches, delay-on and delay-off timing. Gas Valve: Pressure adjustment screws, manifold pressure test ports. Thermostat: Heat/cool/auto modes, fan control, temperature setpoints. Safety Controls: Reset buttons for rollout and limit switches.

Connecting Thermostat

Compatible with standard 24V thermostats and most smart thermostats.

Turn off power to furnace at disconnect switch.
Remove furnace access panel to access control board.
Connect thermostat wires to appropriate terminals (R, W, Y, G, C).
Secure wiring and replace access panel.
Restore power and test thermostat operation.

Tip: Use 18-gauge thermostat wire for runs under 50 feet; 16-gauge for longer runs.

Operating Instructions

Normal operation through connected thermostat.

Set thermostat to desired temperature and HEAT mode.
Furnace will initiate startup sequence: inducer motor, pressure switch verification, ignition, main burner activation.
Blower motor will start after warm-up period.
System will cycle on and off to maintain set temperature.
For shutdown: Set thermostat to OFF or lower temperature below room temperature.

WARNING! Never attempt to adjust gas pressure or safety controls without proper training and equipment.

Maintenance Procedures

Regular maintenance ensures optimal performance and safety.

Monthly: Check and replace air filter as needed
Seasonal: Inspect vent system for obstructions
Annual: Professional inspection and cleaning
Every 2 years: Heat exchanger inspection
As needed: Blower wheel cleaning and motor lubrication

Care & Cleaning

Turn off power and gas supply before cleaning. Use soft brush and vacuum for dust removal.

CAUTION! Do not use water or liquid cleaners on electrical components. Keep combustion area clean and free of debris.

Regulatory Information

UL certified for safety standards. ANSI Z21.47 compliant for gas-fired central furnaces. Meets DOE energy efficiency requirements. For support, visit www.maratherm.com or contact 1-800-555-HEAT. All installations must comply with local building codes and regulations.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, safety switch	Check circuit breaker, thermostat settings, reset safety switches.
No heat	Gas supply, ignition	Verify gas valve on, check for spark at igniter, listen for gas valve click.
Short cycling	Dirty filter, airflow	Replace air filter, check for blocked vents or returns.
Blower won't stop	Thermostat, control board	Check thermostat fan setting, test limit switch, inspect control board.
Unusual noises	Motor, blower wheel	Inspect blower wheel for debris, check motor bearings, tighten components.

Reset: Turn power off for 30 seconds then restore. Check diagnostic LED for error codes.

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