Thermo Scientific Prima PRO User Manual page 199

Air Conditioner
Fault Diagnosis
E-4 Prima PRO & Sentinel PRO Mass Spectrometers User Guide
a + c
c
Discrepancy Possible c
(>3˚C
)between
Gasworks &
air con
temperature
readouts, not
controlling
Cabinet c
temperature
not cycling
and reading
low
Cycling time Possible c
>6 minutes (intermittent)
Liquid None
(water) in
condensate
drain tube to
instrument
enclosure
required.
Ambient System designed for
temperatures up to 40˚C max.
temperature
high
Pressure switch Check status when powered off
fault & cool. If still in alarm, this
suggests a pressure switch fault.
Refrigerant Check for leaks. Refill, as per
charge low specification on air conditioner
label.
Pressure switch
fault
Check internal fan – should be
Internal fan
failure running continuously. If not,
check supply and if fan can be
rotated freely.
Compressor Check compressor operation
failure (e.g. vibration, total current
drawn).
Fault in air con Check mounting of sensors to
sensor or air con grille.
controller Check sensor connections.
Check response of sensors to
Fault in
forced temperature changes e.g.
instrument
hand heat.
sensor or read-
Use an independent temperature
back via ASU
measuring device to determine
which is correct.
Cooling Check operation of temperature
controller output contacts –
continuously,
not regulating these may not be switching
correctly.
Check bypass valve – coil
resistance (not open circuit) and
supply (should be on when
temperature below set point)
Bypass timeout Check if compressor is
operating switching off in each cycle.
Possible temperature controller
fault.
Air con being Switch off air conditioner when
operated with door is open for any significant
enclosure door time (depends on ambient
open humidity).
Enclosure purge Use instrument grade air with a
air has too high suitable known dew point.
water content
Thermo Fisher Scientific