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TM 07661B-14/1
APPENDIX A
(b)
If ambient temperature is above 40, remove the thermostats from the fire extinguisher and place
them in a refrigerated area (example: refrigerator, box of ice, etc.) and check continuity to see which or both thermostats
are faulty. No continuity indicates contacts are not closing and thermostat is malfunctioning.
b.
Heater Insulation Replacement.
(1)
Remove AFFF tank from skid. Refer to paragraph 3-13a.
(2)
Remove the enclosure cover (figure 3-28) from the enclosure or insulation wrapper by removing two
screws. Disconnect the wires from the two heater blankets and two pieces of heat tape.
(3)
Remove two screws, lockwashers, and nuts securing upper and lower insulation wrappers together.
(4)
Remove the two thermostats.
(5)
Remove upper and lower insulation wrappers and insulation from AFFF tank.
(6)
If insulation on tank outlet and shutoff valve needs replacement proceed as follows: (a) Remove the
insulation protectors from the elbow and shutoff valve. Be careful not to damage the protectors.
(b)
Remove the insulation from the elbow shutoff valve and pipe, and replace them with new insulation.
(c)
Install protective covering previously removed.
(7)
Place new insulation on top of AFFF tank, and on top of lower insulation wrapper.
(8)
Place upper insulation wrapper over the insulation. Hook the lower insulation wrapper into the upper
insulation wrapper.
(9) Coat the contacting surface of each thermostat with heat sink paste. Install each thermostat in its hole in
the lower insulation. Be sure wires are placed through holes first.
(10)
Bring the upper and lower insulation wrappers together and clamp in place. Install two screws,
lockwashers and nuts. Remove clamp.
(11)
Reconnect the wires using wiring diagram Figure 3-27 as a reference.
(12)
Install the enclosure cap using two screws.
(13)
Seal the insulation exposed around the fill collar with sealant to prevent water from settling around fill
collar and being absorbed into insulation.
(14)
Install AFFF tank to skid using instructions in paragraph 3-13d.
c.
Thermostat Replacement.
NOTE
AFFF tank assembly need not be removed from skid to replace a thermostat, but with the tank
removed, replacement will be easier.
(1)
Remove AFFF tank from skid. Refer to paragraph 3-13a.
A 3-58
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