These are PDF files that I scanned of original service documents . For best results, right click and save the files. These links were broken for a bit- they work now- sorry for the inconvenience!
| DuoTherm Obsolete Furnace Manuals Service manuals | |
|---|---|
| 659 Series Owners manual (through -049, but applies somewhat to later models, as well) | 659 Owner/ Service manual (seven pages) |
| Direct Spark Ignition System Service Guide | DSI service |
| Pilot type troubleshooting guide. | Pilot system |