Thermo NESLAB HX 150 - Troubleshooting Runaway Hot

8
START
Is
Setpoint
> actual
?
Normal
response
Calibration
Error
NO
YES
Replace
valve
Test
STOP
Refer to
ELECTRICAL & CONTROL
section
Drawing 68.cfl
Rick Mills
13 March 1995
YES
NO
Valve is
stuck closed
Not a
refrigeration
problem
See VALVE
REPLACEMENT
UNSURE
Can you
get cool
lamp on? *
Is
cool lamp
on?
YES
NO
NO
YES
NO
YES
NO
YES
NO
YES
*by manipulating setpoint
See TROUBLESHOOTING:
"WEAK COOLING"
Any
DC volts
on coil
?
Any
AC volts
on coil
?
Is
coil
on?
Problem is in
Controller or
Sensor
Is it
cooling
at all ?
Troubleshooting Chart: Runaway hot