Parr Instrument 6400 - Manual (Page 77)

Troubleshooting
6400 11
w w w . p a r r i n s t . c o m 75
The third condition can be eliminated by following
the procedure outlined in the section servicing the
O-rings on the 966DD2 piston and carefully inspect-
ing the 1/8 nylon pressure hose and associated
compression fittings for leaks while this circuit is
maintained at operating pressure, using the calorim-
eter I/O diagnostics. A minute leak will result in a
significant reduction in upward thrust.
Confirm Correct Operation of the A1251DD Solenoid Valve
If the piston does not move, it is worthwhile at this
point to confirm that both sections of the A1251DD
are working properly (Figure 14-6). For the location
of the A1251DD assembly, Figure 14-3.
Disconnect the 1/8 nylon pressure hose at the elbow
connection nearest the back panel by using a 7/16
wrench. Apply power to the unit and re-enter the
I/O diagnostics. Turn the exhaust output on. The
solenoid should click and oxygen should flow from
the elbow connection on the A1251DD. Turn the
exhaust output off and re-connect the nylon pres-
sure hose. Disconnect the 1/8 nylon pressure hose
at the middle connection. Activating the bomb seal
output should produce a click from the solenoid and
a flow of oxygen at the elbow.
Turn off the bomb seal output and reconnect the
nylon pressure hose. If neither solenoid produces a
flow of gas when activated and the O2 FILL key does
not produce a flow of gas, then, in all likelihood,
the 527VB flow restrictor is plugged and should be
replaced. If only one of the solenoids sources gas
when activated, then the problem must be further
diagnosed as either being electrical (I/O board,
solenoid coil or external wiring) vs. mechanical (in
the valve) and dealt with in an appropriate manner.
If either solenoid sources gas when it is off (i.e.
leaks) then replacement of the entire A1251DD sole-
noid assembly is indicated. For reference purposes,
the normal upward thrust generated by the 966DD2
piston is 50 pounds. The downward thrust is 20
pounds. Far less than 20 pounds are required to
move the piston in either direction when the bomb
is not pressurized.
Jacket Temperature Troubleshooting
The jacket temperature is monitored with the use
of a thermistor installed in the A1448DD tempera-
ture control assembly. This assembly is heated by
a heater cartridge, A1459DD. In the Diagnostics
Menu, select Instrument Monitor. If the heater PID
is ON and reading 100%, yet the jacket is at ambient
temperature, check the following possible causes.
If the heater PID is OFF, the heater and pump must
be turned on in the Calorimeter Operation screen to
perform the troubleshooting steps.
Caution!
Turn off the power to the calorimeter prior
to attempting to reset the thermostat. The
temperature control assembly can become
very hot. Use caution when servicing this
area of the calorimeter.
If line voltage (115V or 230V) is present across the
heater cartridge connection, check the resistance
across the heater cartridge. Approximately 70 ohms
will be seen with a 115V calorimeter. Approximately
140 ohms will be seen with a 230V calorimeter. If
the resistance is not correct the heater may have
failed.
If the voltage is not present, then examine the 2040E
thermostat reset button. If the reset button extrudes
this means that the temperature in the temperature
control assembly has exceeded 75ºC. Confirm that
water is flowing through the system, turn off the
power and then reset the switch by depressing the
button. If the thermostat continues to trip even
though water is flowing through the system, refer to
the error code “There Is A Problem With The Jacket
Thermistor” for further troubleshooting.
If there is no voltage present, and the reset button
on the thermostat is not tripped, refer to the error
code “There Is A Problem With The Jacket Thermis-
tor” for further troubleshooting. There may also
be a problem with the calorimeter controller,
A1250DD2, and Parr service should be contacted.