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