Comfortmaker Enviro Plus 90 Furnace Manual

The Comfortmaker Enviro Plus 90 is a high-efficiency gas furnace with 90% AFUE rating, featuring variable-speed blower motor, electronic ignition, multi-speed operation, and advanced diagnostic controls. Designed for residential heating applications with natural gas or propane capability. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation Requirements 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Venting and Combustion Air 7. Operation Instructions 8. Maintenance Procedures 9. Safety Features 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Heat exchanger, variable-speed blower motor, electronic ignition system, pressure switches, flame sensor, control board, gas valve, and diagnostic LED.

Feature	Description
AFUE Rating	90% Annual Fuel Utilization Efficiency
Blower Motor	Variable-speed ECM for efficient operation
Ignition System	Hot surface electronic ignition
Heat Exchanger	Stainless steel primary and secondary
Gas Type	Natural gas or propane (conversion kit required)
Control System	Integrated furnace control with diagnostics
Pressure Switches	Verify proper venting operation
Flame Sensor	Monitors burner flame presence
Filter System	Standard 1-inch or 4-inch media filter
Thermostat Connection	Standard 24VAC compatible

Installation Requirements

Professional installation required. Ensure proper clearances and local code compliance.

Location: Install in approved locations with proper clearances (see specifications).
Venting: Use approved PVC or CPVC for vent pipes; follow manufacturer specifications.
Gas Connection: Use proper pipe size; pressure test for leaks.
Electrical: 120VAC power supply with proper grounding.
Ductwork: Ensure proper sizing and sealing.

WARNING! Gas appliances can be hazardous; installation must be performed by qualified technician. Carbon monoxide hazard exists with improper installation.

First-Time Setup

Initial startup must be performed by qualified technician.

Verify all connections: Gas, electrical, venting, and ductwork.
Check gas pressure: Adjust manifold pressure per specifications.
Test safety controls: Verify pressure switches, limit controls, and flame rollout.
Program thermostat: Set heating parameters and fan control.
Test operation: Run through complete heating cycle.

CAUTION! Never bypass safety controls. Ensure proper combustion air supply.

Specifications

Model Series: Enviro Plus 90
AFUE Rating: 90%
Input BTU/H: 40,000 - 120,000 (varies by model)
Output BTU/H: 36,000 - 108,000 (varies by model)
Gas Type: Natural gas (LP conversion available)
Electrical: 120VAC, 60Hz
Blower Type: Variable-speed ECM
Venting: PVC/CPVC (2" or 3" diameter)
Sound Level: < 65 dBA
Warranty: Limited lifetime heat exchanger, 5 years parts

Controls and Settings

Integrated control board with diagnostic LED. Access door switch for safety.

Control Board: LED status light (flash codes for diagnostics), DIP switches for configuration.

Thermostat Settings: Heat mode, fan auto/on, temperature setpoint. Blower Speeds: Multi-tap transformer for heating/cooling speeds. Gas Valve: Manual shutoff, pressure regulator. Limit Controls: High temperature safety, fan control limits.

Venting and Combustion Air

Direct vent system using PVC pipes for intake and exhaust.

Vent Pipe: Use only approved PVC or CPVC material.
Clearances: Maintain proper clearances from combustible materials.
Terminations: Follow manufacturer specifications for vent terminal locations.
Combustion Air: Ensure adequate fresh air supply for proper combustion.

Tip: Vent pipes must be properly supported and sloped for condensation drainage.

Operation Instructions

Normal operation controlled by thermostat.

Set thermostat to desired temperature in HEAT mode.
Furnace will initiate ignition sequence when heat is demanded.
Blower will start after heat exchanger warms up (fan delay).
Furnace will cycle on/off to maintain set temperature.
For continuous fan operation, set thermostat to FAN ON position.

WARNING! Never operate furnace with access panels removed. Carbon monoxide poisoning hazard.

Maintenance Procedures

Regular maintenance required for optimal performance and safety.

Monthly: Check and replace air filter as needed.
Annual: Professional inspection and cleaning.
Burner Inspection: Clean burners and heat exchanger.
Blower Maintenance: Clean blower wheel and housing.
Vent System: Inspect for obstructions or damage.

CAUTION! Turn off power and gas supply before performing any maintenance.

Safety Features

Multiple safety systems protect against hazardous conditions.

Safety Feature	Function
Flame Rollout Switch	Detects flame outside combustion chamber
High Limit Switch	Prevents overheating
Pressure Switches	Verify proper venting operation
Flame Sensor	Monitors burner flame presence
Ignition Control	Safe ignition sequence with trial for ignition
Door Switch	Shuts off unit when access panel is removed

Regulatory Information

UL listed and ANSI certified. Complies with applicable safety standards. Manufactured to meet efficiency standards. For technical support, contact Comfortmaker at 1-800-772-9200 or visit www.comfortmaker.com. Installation must comply with local building codes and NFPA 54/National Fuel Gas Code.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, door switch	Check power supply; verify thermostat setting; ensure door panel secure.
No heat	Gas supply, ignition	Verify gas valve on; check for ignition lockout; observe LED flash codes.
Blower won't run	Motor, capacitor, control	Check blower door switch; verify motor operation; inspect capacitor.
Short cycling	Filter, limit switch	Replace dirty filter; check for blocked vents; verify proper airflow.
Unusual noises	Blower, heat exchanger	Inspect blower wheel; check for loose components; examine heat exchanger.

LED Codes: Refer to control board flash pattern for specific diagnostic information.

Service: 1-800-772-9200; www.comfortmaker.com