Viking FDSB5481 - Defrost Terminator; Float Switch

Disassembly
28 ©2012 Viking Preferred Service
WARNING!
To avoid risk of electrical shock, personal injury, or death, disconnect electrical power source to unit, unless
test procedures require power to be connected. Ensure all ground wires are connected before certifying unit as
repaired and/or operational.
Defrost Terminator
The defrost terminator is a bimetal switch
that is normally open. Below 20+/-8.5 ˚F,
the terminator is closed. In order to test, rst
switch the main power switch to “Off”. Locate
the brown wire on E5 of the HV board.
Unplug the wire and check for continuity
between the brown wire and the black wire
at E10. If “0” is read then the bimetal is
closed. It innity (∞) is read, the bimetal is
open.
Note: Freezer temp must be below 20+/-8.5
˚F in order to check for a defective bimetal.
Another method to test can be achieved by
testing at the 15-wire Molex plug on the right
side of the Control Housing. Refer to page
82 pin locations.
To access the defrost terminator:
1. Follow steps 1-4 under Defrost Heater
disassembly.
2. Unclip the terminator, disconnect wiring,
repair/ replace terminator.
Defrost Terminator
3. Reverse procedure to reinstall.
Float Switch
The unit uses a float switch in conjunction
with the drain pan heater to vaporize
condensate created from the refrigerator
cooling process. The switch is normally open
and closes as the water level in the pan
rises thus energizing the drain pan heater.
When the water is vaporized the switch
opens removing power from the drain pan
heater.
To access the float switch, remove the lower
access panel and the float switch is now
accessible. Verify the switch reads innite
resistance when in the down position and
0 Ω in the up position. If the switch does
not open or close properly, replace the float
switch.