Amana GUCA090AX50 User Manual

Service
Instructions
40" 90% Condensing Gas Furnaces
GUCA, GCCA & Accessories
This manual is to be used by qualified HVAC
technicians only. Amana does not assume
any responsibility for property damage or
personal injury for improper service proce-
dures done by an unqualified person.
RS6610002
Revision 0
October 1998
A
higher standard of comfor
t
Heating
n
Air Conditioning
®
Model and Manufacturing
numbers listed on page 4.

Amana GUCA090AX50 Specifications

General

Brand	Amana
Model	GUCA090AX50
Category	Furnace
Fuel Type	Gas
Heating Capacity	90, 000 BTU
Stages	Single Stage
BTU Output	90, 000 BTU
Dimensions (H x W x D)	29.5 x 21.5 x 26 inches
Weight	140 lbs

Summary

IMPORTANT INFORMATION

IMPORTANT NOTICES

Crucial safety alerts and warnings regarding service and potential hazards.

PRODUCT IDENTIFICATION

FURNACE ACCESSORY KITS

Lists available kits for enhancing furnace functionality like twinning or altitude adjustments.

ADDITIONAL FURNACE ACCESSORIES

Details other optional accessories such as air cleaners and filter racks.

COUNTERFLOW FLOOR BASE

Specifications and dimensions for a specific base accessory for counterflow furnaces.

EXTERNAL FILTER RACK KIT

Information on the external filter rack kit, including its application and dimensions.

MEDIA AIR CLEANER

Specifications and dimensions for the media air cleaner accessory.

ELECTRONIC AIR CLEANER

Specifications and dimensions for the electronic air cleaner accessory.

CONCENTRIC VENT CONVERSION KIT

Details on the concentric vent kit for direct vent installations.

FURNACE SPECIFICATIONS

Blower Performance Specifications

Data on blower CFM, static pressure, and motor speeds for various furnace models.

COMBUSTION AND VENTILATION AIR

AIR REQUIREMENTS

Guidelines for ensuring adequate air for combustion and ventilation as per NFPA standards.

5.3.1 General

General provisions for gas utilization equipment regarding air supply for combustion.

5.3.2 Equipment Located in Unconfined Spaces

Criteria for determining adequate air supply in unconfined building spaces.

5.3.3 Equipment Located in Confined Spaces

Requirements for air supply in confined building spaces, including openings.

CONDENSATE DRAIN LINES AND DRAIN TRAP

Condensate Drain Lines and Drain Trap General

Explains the need for condensate management in condensing furnaces.

Upright Installations

Instructions for connecting drain hoses and traps in upright furnace installations.

PRODUCT DESIGN

Safety

Critical warnings and cautions for safe installation, operation, and servicing.

Electrostatic Discharge (ESD) Precautions

Steps to protect electronic components from static discharge during handling.

Product Application

Defines the intended use and certification of the furnace product.

Location Requirements and Considerations General

Guidelines for selecting a proper furnace installation location.

Furnace Suspension

Methods for suspending the furnace from joists or supporting it on a pad.

SYSTEM OPERATION

Normal Sequence of Operation

Describes the step-by-step process for heating, cooling, and fan-only modes.

Troubleshooting

Covers common operational issues and troubleshooting steps for the furnace.

POLARIZATION AND PHASING

CHECKING FOR PHASING - PRIMARY TO SECONDARY OF UNMARKED TRANSFORMERS*

Procedures for verifying transformer phasing for proper electronic control operation.

MAINTENANCE

ANNUAL INSPECTION

Recommendations for yearly checks to ensure proper furnace operation and safety.

Filter Removal

Instructions for removing filters based on different installation types.

SERVICING

TEST EQUIPMENT

Lists essential tools required for accurate furnace diagnosis and repair.

HEATING PERFORMANCE TEST

Steps to conduct a heating test and calculate BTU input for performance analysis.

SERVICING

S-1 CHECKING VOLTAGE

Procedure to check line voltage and verify furnace power supply.

S-2 CHECKING WIRING

Steps for visually inspecting and testing wiring for continuity and damage.

S-3 CHECKING THERMOSTAT, WIRING, AND ANTICIPATOR

Guide for testing thermostat connections, wiring, and heating/cooling anticipators.

SERVICING

S-4 CHECKING TRANSFORMER AND CONTROL CIRCUIT

Procedure to test the step-down transformer and the integrated control circuit.

S-5 CHECKING PRIMARY LIMIT CONTROL

Steps to test the primary limit control for proper operation and temperature settings.

S-6 CHECKING AUXILIARY LIMIT CONTROL

Guide for testing the auxiliary limit control mounted in the blower compartment.

S-7 CHECKING BLOWER MOTOR

Instructions for testing blower motor continuity and ground connections.

SERVICING

S-8 CHECKING CAPACITOR

Procedures for testing motor capacitors for resistance and capacitance.

S-9 CHECKING GAS VALVE (Redundant)

Steps to test the gas valve coil for continuity and proper operation.

SERVICING

S-10 CHECKING MAIN BURNERS

Inspection of main burners for signs of rust, port restrictions, and alignment.

S-11 CHECKING ORIFICES

Guidance on checking and replacing fixed gas orifices, especially for altitude adjustments.

SERVICING

S-12 CHECKING GAS PRESSURE

Procedure for measuring and adjusting inlet gas supply and manifold pressures.

SERVICING

S-13 CHECKING FOR DELAYED IGNITION

Steps to diagnose and correct delayed ignition issues in the combustion chamber.

S-14 CHECKING FOR FLASH-BACK

Procedures to identify and resolve flash-back problems in the burner venturi.

SERVICING

S-15 CHECKING DUCT STATIC

How to measure static pressure in return and supply ducts for airflow analysis.

S-16 CHECKING TEMPERATURE RISE

Method for measuring temperature rise across the heat exchanger and adjusting airflow.

SERVICING

S-17 CHECKING PRESSURE CONTROL

Steps to test induced draft blower and coil cover pressure controls.

S-18 HIGH ALTITUDE APPLICATION (USA)

Information on necessary adjustments for furnaces installed at high altitudes.

SERVICING

S-19 CHECKING MINI IGNITER

Procedure to test the mini igniter's resistance and current draw.

S-20 CHECKING WHITE-RODGERS 50A55-288 OR HEATCRAFT HSI-2 INTEGRATED IGNITION CONTROL MODULES

Guide for diagnosing issues with specific ignition control modules.

SERVICING

S-21 CHECKING FLAME SENSOR

Steps to test the flame sensor for proper micro-amp signal and positioning.

SERVICING

S-22 CHECKING FLAME ROLLOUT SWITCH

Procedure to test the flame rollout switch for continuity and proper operation.

SERVICING

Removal of Existing Heat Exchanger:

Instructions for safely removing the existing heat exchanger assembly.

S-23 HEAT EXCHANGER ASSEMBLY

Details on replacing the heat exchanger assembly as a single unit.

SERVICING

Reinstallation of New Heat Exchanger:

Steps for installing a new heat exchanger and performing post-installation checks.

WIRING DIAGRAMS

SCHEMATICS