Specifications

Instruction 3015-4256 13
3 Operation
Front Panel Display & Controls
General Operation
Once the HGM-SZ has been installed, set up, and powered ON, the monitor will make measurements in the
area being sampled for refrigerant gas without further operator intervention. The results of those measurements
are shown on the front panel display.
In the example shown above, MEASURE indicates that the HGM-SZ is actively monitoring for refrigerant gas,
and that currently 45 ppm of R-134A (refrigerant gas) is being detected. This display also indicates that a peak
measurement of 485 ppm has been made.
An operator can reset the peak value to zero by pressing the ENTER button.
A log of up to 200 previous measurements can be viewed using the PPM LOG function (Page 15).
If the detected gas level exceeds the preset Leak, Spill, or Evacuate alarm point, then the monitor responds by
turning ON the front panel ALARM (red) light and energizing the corresponding alarm relay. If the internal
audible alarm is turned ON, it too will activate (AUDALRM page 16). Optional external alarm devices can be
connected to the alarm relays to alert personnel that a Leak, Spill, or Evacuate alarm condition has occurred
(Page 10). Pressing the front panel SILENCE button will acknowledge an alarm and turn OFF all alarm
indicators with the exception of the front panel ALARM light. The alarm circuit will reactivate, however, if the
alarm condition is not cleared within the time period set by the SILENCE function (Page 16). The ALARM light
will turn OFF after the detected gas level goes below the lowest alarm point and after the SILENCE button is
pressed.
M
EASURE 00485
p
k
45ppm R134A
Display
Screen
ENTER
Press this button to:
1. Clear peak reading
2. Save a function screen’s
displayed value
Keypad
Use these buttons to:
1. Enter function mode,
then move arrow (>)
on screen to the
desired function
2. Scroll through data
3. Change a function’s
value
MONITOR ON
LED (Green)
1. Flashes during
warm-up
2. Lights steady
during normal
operation
SYSTEM FAULT
LED (Yellow)
Flashes when
one or more of
the faults listed
on Page 19 occur
A
LARM Light
(Red)
Flashes when
detected gas
level exceeds
any of three
preset alarm
points.
SILENCE / QUIT
Press this button to:
1. Acknowledge a system
fault or gas alarm by
turning OFF the
internal audible alarm
and de-energizing the
corresponding
fault/alarm relay.
2. Return to the previous
screen without saving
data when in the
function mode.