Emerson VH Setup Operation, Setup functions and factory default values, Function Default Range

Advanced Microprocessor Controls Setup

Setup Operation

The Setup Operation permits the review and/or adjustment of the unit configuration. The menu may include:

Cold Start: This feature, also referred to as Positive Start or Winter Start Kit, allows for the low- pressure switch to be ignored for the programmed time during a cold start of the compressors, enabling the unit to run at low suction pressures. Entering a “0” for this time will bypass this feature. A “1”, will bypass the low-pressure switch for one minute, a “2” for two minutes, etc. The programmed value can be from 0 to 3 minutes. This delay is factory set to 0 for water-cooled, glycol cooled, and GLYCOOL™ units. Typically, only air-cooled units need a “Winter Start” time.

Restart: This feature allows for the unit to restart automatically after a loss of power. The pro- grammed value is in 0.1 minute (6 seconds) intervals. A programmed value of zero (0) would require the user to manually press the ON/OFF key to start the unit, i.e. no auto restart. The purpose of this feature is to prevent several units from starting at the same time after a loss of power. The message “Restart delay -- Please wait” will be displayed when the system is in the AUTO RESTART mode. (It is suggested that multiple unit installations be programmed with different auto restart times.)

IR Fill Rate (infrared humidifiers only): An autoflush system automatically controls a water makeup valve to maintain proper level in the infrared humidifier water pan during humidifier operation. If humidification is needed and 15 hours have elapsed since the last time the humidifier was on, the humidifier is held off until the valve completes an initial fill of the humidifier pan. This pre-fill is about 35 seconds for a small pan and 60 seconds for a large pan. The valve continues to fill and flush the pan for about 4 1/2 minutes for a small pan or 7 1/2 minutes for a large pan. Pan size is selected based on unit specifications and is preset at the factory.

During humidifier operation, with the flush rate set at the default of 150%, the valve is opened peri- odically to add water to the pan (about 45 seconds every 7 minutes of humidifier operation for a small pan, or 80 seconds every 10 minutes of operation for a large pan). This adds enough water to the pan to cause about a third of the total water used to be flushed out the overflow standpipe located in the humidifier pan. This action helps to remove solids from the pan. The flush rate is adjustable from 110% to 500%. If the water quality is poor, it may be desirable to increase the water flushing action above the normal 150% rate. Also, if the supply water pressure is low, the flush rate adjustment can be increased so that sufficient water level is maintained during humidification.

Chilled Water/Hot Water/Econ-O-Coil Flush: This feature will flush the respective coil for three

(3)minutes after the programmed number of hours of non-use. For example, if the flush time is pro- grammed with 24 hours on a hot water reheat type system and heating is not required for 24 hours, the hot water valve will be open for three (3) minutes to allow the coil to be flushed. The programmed value can be from 0 (zero) (no flush) to 99 (99 hours of non-use).

F/C Degrees: The control can be selected to show readings and setpoints in either degrees Fahren- heit (°F) or Celsius (°C).

The following table lists the Setup functions, their factory default values, and the allowable ranges that can be programmed:

Table 2	Setup functions and factory default values
Function		Default	Range
Cold Start Time Delay*		3	0 to 3 min (0 = no delay)
Restart Time Delay		0.1	0 to 9.9 min (0 =manual restart)
Infrared Fill Rate		150	110 to 500%
Chilled/Hot Water		24	0 to 99 hrs (also Econ-o-coil)
Coil Flush
F/C Degrees		F	C or F
*Factory set to 0 for water-cooled, glycol, and GLYCOOL™ units.

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