TM 10-4520-259-13&P
5-14.
CONTROL BOX ASSEMBLY (CONT)
v.
Test the K-1 post purge relay (641-9974/6-1-9973) by checking for continuity between pins 2 and 5,
and
6 and 10. Meter should indicate continuity.
w.
Check for closed contacts between terminals 1 and 4, and 8 and 11. Meter should indicate 0 ohms.
x.
Check for open contacts between terminals 1 and 3, and 9 and 11. Meter should indicate infinity.
y.
Replace relays if other readings are obtained.
REMOVE
a.
Remove receptacle (1) from control box (2), by removing four screws (3), cover plate (4) and gasket (5)
with receptacle (1).
b.
Tag and disconnect five wires (6) connected to the rear of the receptacle (1).
c.
Remove three screws (7) from under the cover plate (4).
NOTE
Two different power switches may be found. One (old style) incorporates overload
heaters, the other (new style) does not.
d.
Remove the power switch (8) by removing two screws (9) and remove gasket (10).
e.
Turn load power switch (8) over.
f.
Tag all wires (11). Remove six screws (16), wires, and power switch (8) from control box (12).
g.
Tag wires connected to low water relay (14). Remove eight screws (15) securing wire lugs to terminals.
Loosen three screws (16) and raise up and remove low water relay from circuit box (17).
Change 2 5-42
