Using Hold Mode vs Steam On/Off
As we have been out working with and training steamer operators, we have noticed some misunderstanding of the purpose of “Hold” mode and the proper use of the “Hold” feature versus “Steam On/Off.” We have noticed that many operators are using “Hold” to shut the steam off at the end of a windrow when turning around, rather than using “Steam On/Off.” The following will explain the difference between these two features and when and how to use each.
Steam Purge System
In order to produce consistent bale moisture, DewPoint machines need to run at a constant pressure. The control system of the DewPoint machines is designed so that the burner will automatically alternate between High Fire, Low Fire, and Off to maintain the boiler pressure within 1 psi of the target boiler pressure (12 psi). While baling with the steam on, the burner will normally run constantly, alternating between Low Fire and High Fire to maintain consistent pressure. When the steam is turned off while stopping or turning around and at the end of a windrow, steam pressure will continue to build while the burner runs on low fire. If the boiler pressure exceeds 1 psi above the target, the burner will turn off and wait for the boiler pressure to drop before it will turn back on. When the burner turns back on, it takes 30-60 seconds to complete the purge and ignition states before the fire will light and begin building pressure again. If you are baling with the steam on while the burner is restarting, you will lose a significant amount of steam pressure before the fire can be restarted. So, in order to keep the burner running at all times during normal operation, DewPoint machines are equipped with a “steam purge” valve that will open to relieve boiler pressure and allow the burner to keep running when steam is not being used in the baler. Steam purge is critical to maintaining consistent steam pressure during normal operation.
- What is Hold Mode: Hold mode is a feature that will disable all steam discharge from the DewPoint machine and will allow the machine to “Hold” in a standby state. Hold mode disables the steam valves as well as the steam purge and blowdown valves. When in hold mode, the burner stays active and will cycle on and off to maintain the steam pressure within 1 psi of the target boiler pressure (12 psi).
- When to use Hold Mode: Hold mode is meant to be used when stopping in the field for quick repairs, checking bales, or any time you will be stopping but you want the machine to remain on and ready.
- When NOT to use Hold Mode: Hold mode is NOT meant to be used at the end of a windrow while turning around during normal operation. This will disable critical machine functions such as steam purge and blow down and will result in significant variation in steam pressure and bale quality. ALWAYS use the standard steam On/Off function when turning around at the end of a windrow during normal operation.
- What is Steam On/Off: Steam On/Off turns the steam flow to the baler on and off. All other machine functions stay active including blow down and steam purge. The steam purge will open only as needed to keep the burner on and maintain a consistent steam pressure during operation.
- When to use Steam On/Off: Use Steam On/Off when turning around at the end of a windrow or when stopping for very short periods of time in the field.
- When to use Hold Rather than Steam On/Off: Use Hold rather than Steam On/Off when stopping in the field for any extended amount of time.
We hope this information is helpful. If you have any questions about this or any other questions about how to best operate your DewPoint machine, please Contact Us. We will be happy to help.