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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
(b)
Make sure that the current is 0.25 amps or more.
(c)
As an alternative method to the current measurement, feel the heated supply hose with your hand to make sure that it is warm.
S 085-031
(4)
Remove the clamp-on ammeter.
S 415-036
(5)
Install the cargo liners or floor panels (AMM 25-52-01/401).
J. In-Line Heaters Test
S 015-037
(1)
Remove the applicable cargo liners or floor panels to get access to the in-line heater (AMM 25-52-01/401).
S 485-032
(2)
Connect a clamp-on ammeter around one of the two heater power wires.
S 715-033
(3)
Do a check of in-line heater operation:
(a) Make the heater thermostat cool with dry ice or freon spray (the thermostat is in the thin tube between the controller body and the B-nut).
NOTE: To use the freon spray, apply the spray to the
____ thermostat for 2 seconds. After 5 seconds apply the spray again. Do this procedure as many times as necessary to make the thermostat sufficiently cool.
(b)
Make sure that the current is 0.6 amps or more.
(c)
Move the clamp-on ammeter to the ground wire.
(d)
Make sure that the current in the ground wire is the same as that found in the power wire.
S 085-040
(4)
Remove the clamp-on ammeter.
S 415-041
(5)
Install the cargo liners or floor panels (AMM 25-52-01/401).
K. Test of the Blanket Heater for the Waste Tank Drain Line
S 015-066
(1) Remove the applicable cargo liners or floor panels to get access to the waste tank blanket heaters (AMM 25-52-01/401).
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30-71-00
ALL ú ú 08 Page 506 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
S 485-067
(2)
Connect a clamp-on ammeter around one of the two heater power wires.
S 715-068
(3)
Do a check of waste tank blanket heater operation:
(a) Make the heater thermostat cool with dry ice or freon spray.
NOTE: To use the freon spray, apply the spray to the
____ thermostat for 2 seconds. After 5 seconds apply the spray again. Do this procedure as many times as necessary to make the thermostat sufficiently cool.
(b) Make sure that you find the current shown below: 1) For the valve heater blankets: 0.09 - 0.13 amps 2) For the service panel tube heaters: 0.11 - 0.14 amps 3) For the forward and aft tube blanket heaters: 0.16 - 0.24
amps
S 085-069
(4)
Remove the clamp-on ammeter.
S 415-070
(5)
Install the cargo liners or floor panels (AMM 25-52-01/401).
L. Transfer Relay Air Mode Test
S 865-042
(1)
Open 414A24, WASTE & WATER LINE HTR MN PWR (gnd) circuit breaker on the P414, Left Power Distribution Center.
S 015-043
(2)
Remove the applicable cargo liners or floor panels to get access to the thermostat of a forward in-line heater (AMM 25-52-01/401).
_______
S 485-034
(3)
Connect a clamp-on ammeter around one of the two heater lead wires.
S 715-035
(4)
Do a test of the in-line heater air mode:
(a) Make the heater thermostat cool with dry ice or freon spray (the thermostat is in the thin tube between the controller body and the B-nut).
NOTE: To use the freon spray, apply the spray to the
____ thermostat for 2 seconds. After 5 seconds apply the spray again. Do this procedure as many times as necessary to make the thermostat sufficiently cool.
(b)
Make sure that the current is 0.6 amps or more.
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