Operation And Stabilization; Power Up And Warmup; Stabilization; Perform A Manual Zero - Emerson MRLDS-250 Installation And Operation Manual

4 Operation and

Stabilization

4.1. Power Up and
Warmup
On powering up, the MRLDS-250 will sense for the
presence of gas after an initial warm-up period of two
to five minutes. The green LED will flash at a
one-second interval during the warm up.
4.2. Stabilization
CAUTION: It is vital when first
installing the gas detector that it
warms up in an atmosphere that is
known not to contain any
background concentrations of
refrigerant. Emerson offers portable gas
detectors for this purpose. Contact Technical
Support for more information.
4.3. Perform a Manual
Zero
After the gas detector stabilizes, the power LED stops
flashing and is lit continuously. Emerson recommends
manually zeroing the MRLDS-250 after a 1-hour
stabilization period. Increase this stabilization period
to 3 hours for freezer applications.
To manually zero the gas detector, press and hold the
UP and DOWN buttons simultaneously for 5 seconds.
The gas detector will beep and the display will show
zEro when zeroing is complete. The display will show
fAiL if the temperature is changing too quickly or
there is an active alarm condition. Additionally,
certain system faults (F.-08, F.-10 through 14, and/or
F.-16) will prevent a manual zero from being
performed.

Power Up and Warmup

NOTE: A manual zero should be
performed in the environment of
operation and at the typical
operating temperature.
NOTE: Subsequent manual zeros
may be performed, provided the
atmosphere around the gas
detector is free of all background
concentrations of refrigerant.
Clean air or nitrogen applied to the
calibration port for five minutes may be used
to ensure the gas detector is clear of all
background gas. Re-zeroing with background
refrigerant present will cause the gas detector
to report incorrect readings.
4.4.

Alarms

The following occurs during an alarm condition:
Item Behavior During Alarm State
Green
On (solid)
LED
On (blinks); reports detected PPM
Display
concentration
Audible On (if enabled and after
Alarm programmed delay expires)
Relay Activates (after any programmed
Output delay expires)
Analog Changes proportionally with gas
Output concentration (as configured)
Modbus Registers indicate the alarm
Registers condition, ppm, concentration, etc.
Table 4-1 - MRLDS-250 Behavior During Alarm
Conditions
Operation and Stabilization • 13