Parr Instrument 1356 - Manual (Page 18)

18
8.
Misfire Error
Ignition Problems on the 1356 Calorimeter are generally attributed to one of three
possible sources, after having checked the fuse.
1.
Breakdown of insulator and O-ring on the insulated electrode assembly. Any
reading on an ohm meter when set on RX1 scale when the ohm meter leads are connected
to the ignition terminals of oxygen bomb head is an indication of insulation breakdown.
2.
The ignition lead wires have broken internal wire strands which may be detected
by connecting the ohm meter to the ends of the wire, and flexing the wire. Any change in
the reading of approximately from 0-20 ohms would indicate broken strands of wire.
Readings for bad ignition wires generally go to infinity on flexing the wire.
3.
The third possibility is the connection termination of the 11 pin Wago connector
to the A1135DD control unit. The wire terminations for ignition wire are not fully
inserted into the orange connector.
The voltage output from the 11 pin connector on the
A1135DD control unit may be confirmed with volt meter measurement at pins 6 and 7.
When one turns on line 1 of menu page 9.2 and voltage on large blue capacitor inside the
controller should ramp to approximately 30 volts. If system does not show any ramping,
the charging circuit is at fault. If capacitor charges but the fuse wire does not burn, the
discharge circuit is at fault.
4.
Improperly formed fuse wire may cause misfire. The fuse should be attached by
raising the cap, inserting the wire through the eyelet and then pull the cap downward to
complete the assembly. The bottom portion of fuse wire should touch sample before any
portion of wire touches the capsule.
Error: Calibration Limit Exceeded
This error is generally attributed to a calibration test that caused the range of calibration
tests to be larger than 12 calories/C. The cause of this may be due to the fact that:
1.
The oxygen bomb has 500 firings and requires the replacement of O-rings and
valve seat.
2.
The operator may have used the wrong bomb, that is each bomb is required to
have its own EE value.
3.
An operator is different than the person that established the original EE value, it
may be necessary for each operator to have their own EE value.
4.
The EE value may be an outlier and discarded after using a statistical review
procedure.
5. Discard the first calibration test
6. Be sure that bucket is dried after each run as well as the bomb and the probe and
stirrer.
7.
All tests should be made at the same starting temperature.