(h)  
Potable Water Tank Heater Test

 (i)  
Test of the Heated Supply Hose Below the Water Tank

 TASK 30-71-00-715-001
 2.  Operational Test - Water Line and Waste Drain Heaters_____________________________________________________
 A. Standard Tools and Equipment
 (1)  Clamp-on AC Ammeter
 B. Consumable Materials
 (1)  
B00749, Freon Freeze Spray

 (2)  
G00829, Dry Ice

 C. References
 (1)  
AMM 24-22-00/201, Manual Control

 (2)  
AMM 25-52-01/401, Containerized Cargo Compartment Ceiling and Sidewall Lining

 (3)  
AMM 32-09-02/201, Air/Ground Relay System

 (4)  
SSM 30-71-01, SSM 30-71-02

 (5)  
WDM 30-71-11, WDM 30-71-12, WDM 30-71-13, WDM 30-71-14

 D. Access
 (1)  Location Zone 125 thru 152 - Lower Lobe (Refer to WDM for heater locations)
 E. Preconditions
 S 865-079
 (1)  These conditions are necessary for this task:
 (a)  Electrical power on (AMM 24-22-00/201).
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747-400 MAINTENANCE MANUAL
 (b) Air/ground relay system is serviceable (AMM 32-09-02/201).
 F. Drain Mast Heaters Ground Mode Test
 S 865-002
 (1)  
Supply electrical power (AMM 24-22-00/201).

 S 865-037

 (2)  
Make sure the DRAIN MAST HTR circuit breakers on the P414, Left Power Distribution Center are closed.

 NOTE: The circuit breakers are on rows C, L, and M of the panel.
____
 S 285-004
 WARNING:_______DO NOT TOUCH THE DRAIN MAST. WHEN THE DRAIN MAST HEATER OPERATES, THE DRAIN MAST IS SUFFICIENTLY HOT TO BURN YOU.
 (3)  Make sure drain mast becomes warm.
 NOTE: Hold your hand near the drain mast when it is necessary to
____ monitor its temperature during this procedure. Do not touch the drain mast.
 S 865-006
 (4)  
Open 414M32, DRAIN MAST HTRS GND MODE circuit breaker on the P414, Left Power Distribution Center.

 (5)  
Make sure the drain mast starts to become cool.

 S 865-008

 (6)  
Close 414M32, DRAIN MAST HTRS GND MODE circuit breaker on the P414, Left Power Distribution Center.

 S 755-040
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747-400 MAINTENANCE MANUAL
 S 755-042
 (7)  Make sure the drain mast becomes warm.
 S 865-010
 CAUTION: DO NOT LET THE CIRCUIT BREAKER IN THE STEP THAT FOLLOWS BE
_______ CLOSED FOR MORE THAN 5 MINUTES. THERE CAN BE DAMAGE TO THE FORWARD AND AFT DRAIN MASTS IF YOU CLOSE THE CIRCUIT BREAKER FOR TOO LONG.
 (8)  
Open 414L23, DRAIN MAST HTR AIR CTR circuit breaker on the P414, Left Power Distribution Center.

 S 755-056

 (9)  
Make sure the drain mast starts to become cool.

 S 865-012

 (10)
 Close 414L23, DRAIN MAST HTR AIR CTR circuit breaker on the P414, Left Power Distribution Center.

 G. Drain Mast Heaters Air Mode Test
 S 045-050
 WARNING: YOU MUST CAREFULLY DO THE STEPS IN THE TASK BELOW TO PREPARE
_______ THE SAFETY-SENSITIVE SYSTEMS FOR THE AIR MODE. FAILURE TO DO THE STEPS CORRECTLY CAN CAUSE THE AUTOMATIC OPERATION OF AIRPLANE SYSTEMS. THIS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (1)  
Do this task: "Prepare Safety-Sensitive Systems for Air Mode Simulation" (AMM 32-09-02/201).

 S 865-014

 (2)  
Open these circuit breakers:

 (a)  
P7, Overhead Circuit Breaker Panel
 1) 7F22, LANDING GEAR DSP & CONT PRI
 2) 7F23, LANDING GEAR DSP & CONT ALTN

 (b)  
　
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