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VAPOR-LOGIC
®
VERSION 6 INSTALLATION AND OPERATION MANUAL
When a duct high limit option is ordered, DriSteem provides either a duct
high limit switch or a duct high limit humidity transmitter (4 to 20 mA output,
0 to 100% RH range) for duct mounting .
DUCT HIGH LIMIT SWITCH OPTION
The duct high limit switch prevents duct saturation by turning off the humidifier
when reaching the device set point . When this occurs, a “Duct HL trip”
message appears in the Messages Log and autoclears when duct RH drops
below the duct high limit set point .
MODULATING HIGH LIMIT TRANSMITTER OPTION
The modulating high limit transmitter operates in conjunction with the room/
duct controlling transmitter or demand signal through the Vapor-logic control
system to prevent excess humidification in the duct . Vapor-logic starts lowering
the humidifier output when the duct relative humidity is within a user-defined
percentage (default is 5%) of the duct high limit set point . This value is called
the duct high limit span and is defined during Setup .
When duct relative humidity enters this range, a “Duct HL span” message
appears in the Messages Log and the Message label lights on the keypad/
display . If necessary, the reduction of the humidifier output continues until
maximum high limit set point is reached, shutting off the humidifier completely .
If this occurs, a “Duct HL trip” message appears in the Messages Log .
When the high relative humidity starts to decrease in the duct, Vapor-logic
slowly starts to increase steam production . When the duct relative humidity
decreases to greater than the defined percentage below the duct high limit set
point, the control transmitter or signal by others demand signal is restored as
the primary controller, returning the control system to normal operation, and
the messages in the Messages Log automatically clear .
TEMPERATURE COMPENSATION CONTROL OPTION
Note: This option is not applicable for XT humidifiers .
When selected as an option, DriSteem provides a temperature compensation
transmitter . The temperature compensation transmitter continually monitors
interior window glass temperature and transmits this temperature to
Vapor-logic .
Vapor-logic assumes a 70 °F (21 °C) room temperature and uses the glass
temperature and the RH in the space being controlled to calculate the dew
point (°F or °C) for the space .
OPERATION
Options and features