Atwood 85 Series - User Manual

1
September 2003
INTRODUCTION
The 2004 edition of the Atwood Furnace Service Manual is a resource created to help
service technicians identify Atwood product by serial number, diagnose service
problems and efficiently and effectively process warranty claims.
Changes to the Hydro Flame furnaces include:
• Ignition boards in the 79, 85 and 89 series furnaces now have the blower relay
incorporated into the PC board. These boards are compatible with previous Hydro
Flame furnaces. There is no longer a remote relay.
• New boards have a diagnostic ability with 4 fault codes.
• Furnaces with no outside access doors (only an exhaust vent) became available in
2003; the initials L/D in the model number identify these models. The gas valve was
re-oriented with a longer inlet manifold to make this possible.
Each of the manuals within this series offers a general overview of the product as well
as more specific product information. For each product within the manual, you will find
model identification, recommended tools and equipment, a sequence of operation,
warnings, annual maintenance procedures, parts and troubleshooting guides, warranty
procedures, flat rate schedules, and replacement part reference charts.
Due to the rapidly changing personal computer revolution we have placed
troubleshooting information in a variety of places to make sure that the most accurate
information is available. The best place to find the current information about Atwood
products is our website: www.atwoodmobile.com. At our website brochures may be
downloaded, trouble shooting guides reviewed and the latest information bulletins can
be read. In addition all Atwood Authorized Service Centers are listed on our site,
accessible via an easy-to-use search system.
Service for all Atwood products is handled out of our Rockford location. Should you
have any questions regarding our products or the information contained in this manual
simply dial 1-800-825-4328. Be sure to have the Model and Serial Number when you call.
Atwood Service Department
Disclaimer: The data presented in this publication is obtained from the most reliable sources, and is believed to be accurate as of the date of publication.
Responsibility for typographical errors or omission of data cannot be assumed by the publishers.

Summary

Atwood Furnace Service Tools

Circuit Board Tester

Device to test furnace circuit board functions.

7900-II; 8000-II Wiring Diagrams

85 Series Wiring Diagrams

2-Stage Furnace Wiring Diagrams

Atwood Digital Thermostat Operation

Model 1 H2 C Digital Thermostat

Specifications and operation of the 1H2C thermostat.

Thermostat Installation Guidelines

Procedures for mounting and wiring thermostats.

Model 2 H2 C Digital Thermostat

Specifications and operation of the 2H2C thermostat.

Furnace Operation Sequences

DC Standard One-Stage Operation

Step-by-step operation for DC standard furnaces.

DC 2-Stage Excalibur Operation

Step-by-step operation for 2-stage Excalibur furnaces.

Pilot Model Operation

Step-by-step operation for pilot-lit furnaces.

AC Model Operation

Step-by-step operation for AC furnaces.

Annual Preventative Maintenance Inspection

Furnace Component Details

Circuit Breakers, Motors, and Circuit Boards

Functions and replacement of breakers, motors, and boards.

Relays, Sail Switches, and Limit Switches

Gas Valve and Burner Assembly

Furnace Troubleshooting: The 4 Always

Gas Pressure and Voltage Checks

Verifying gas pressure and electrical voltage.

Ducting and Return Air Requirements

Ensuring proper ducting and return air flow.

Furnace Troubleshooting Guides

Electronic Ignition Furnace Troubleshooting

Diagnosing issues with electronic ignition furnaces.

Pilot Model Furnace Troubleshooting

Diagnosing issues with pilot model furnaces.

Warranty and Claims Procedures

Furnace Limited Warranty and Extended Service

Atwood 85 Series Specifications

General

Model	85 Series
Voltage	12V DC
Thermostat Control	Yes
Fuel Type	Propane
Efficiency	80%