Testing the alarms
Testing of the alarms should be done at least every 6 months or according to institutional protocol.
T
ESTING THE OVER
-
TEMPERATURE ALARM
(43˚
AND
46˚C
ALARM POINTS
)
TOOLS AND EQUIPMENT
• Phillips screwdriver
• IV solution at room temperature
• 1 Ranger standard flow warming cassette instrumented with a thermocouple
(see page 5 for instructions)
• Calibrated thermocouple temperature monitor
Read before testing: The over-temperature alarm test causes the Ranger unit to go into an
over-temperature test mode by manually overriding the primary control system and engaging
the heaters. The Ranger system is very responsive to heater input; therefore, the test proce-
dures are technique sensitive. Read instructions thoroughly before beginning these tests.
The first alarm point at 43˚C alerts you to the rise in temperature (see step 5). At the 46˚C
secondary alarm set point, the unit cuts power to the heaters (see steps 6-8). Please note that
due to tolerance stack-ups between the various systems and the heater's rapid response, you
may see secondary alarm set point readings from 45-49˚C.
TEST SET
-
UP
1. Turn on the Ranger warming unit and allow it to stabilize at normal operating temperature
(40-41˚C) for 30 minutes.
2. Insert the instrumented warming cassette into the Ranger unit.
3. Prime the warming cassette with room temperature IV solution. When primed, clamp the
outlet tube to stop flow.
4. Connect the thermocouple to the calibrated thermocouple temperature monitor to verify
that the warming unit’s temperature has stabilized at normal operating temperature.
5. Slowly loosen the over-temperature screw on the bottom of the Ranger unit (see illustration
below). When the heater reaches 43˚C, an audible alarm sounds, the alarm light
illuminates, and the display alternately flashes “HI” and the plate temperature.
Important note: Steps 6 through 8 are highly dependent upon each other; be sure to read all
steps before proceeding with the alarm test. Newer Ranger units or units fitted with a new
alarm board will test differently than older units. Steps 6a and 6b will help you determine the
unit type you are working on. It is important to note that neither the alarm function nor the
efficacy of the Ranger system has changed, only the mechanism for testing.
Ranger
Blood/Fluid Warming System
6
Screw must be
fully seated for
unit to function
properly.
Over-temperature screw
