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APPENDIX A
TM 07661B-14/1
Table A 3-2. Trouble-Shooting Chart (Continued)
SYMPTOM
PROBABLE CAUSE
POSSIBLE REMEDY
NO AFFF DISCHARGE
In freezing tem-
See AFFF TANK HEATER.
WHEN NOZZLE IS
peratures, AFFF
OPEN, SYSTEM
heater not per-
PRESSURIZED.
forming properly.
.
AFFF TANK HEATER
NOTE
WARNING
All symptoms and
120/240 VAC used
corrections assume
in operation of
temperature below
this equipment.
40F.
DEATH on contact
may result if per-
sonnel fail to ob-
serve safety pre-
cautions.
HEATER DOES NOT
Low voltage from
*Using volt-ohmmeter with
OPERATE AT
power source.
insulated probes, check
CORRECT TEMPER-
continuity of heater and
TURE (AFFF)
thermostats; also check
(partially
voltage across heater
frozen)
power source output termi-
nals. If incorrect,
replace power source.
Defective thermostat.
Replace thermostat.*
HEATER INOPERATIVE
Open or shorted
Disconnect power cord from
AT ANY TEMPERA-
lead in heater
receptacle. Connect ohm-
TURE. (Power
blanket.
meter across the power cir-
Source okay).
cuit terminals of the heat-
ers in the electrical en-
closure. Ohmmeter reading
should be 11 ohms nominal
for the 120 volt connection
or 44 ohms nominal for the
240 volt connection. If
reading is other than this,
check heater wiring and
individual heater for
damage. Replace heater
blanket properly after
any repair work is
completed.
A 3-7
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