TASK
Title:
SHEET 2.4-3E
TESTING ROTARY SWITCH
Performance Objective: In air conditioning shop scenario, the trainee
must be able to test the different types of
switches used in servicing the control circuit
Supplies/Materials
Equipment
Tools
:
:
Paint brush, Rotary Switch
Air Conditioning unit
:
Long Nose Pliers , Multi-Tester
Personal Protective Equipment :
Gloves, mask, goggle, safety shoes
Steps/Procedure:
Selector switch is a mechanical control intended to turn on the fan
and compressor of the air-conditioning unit. It is also the control for the
different fan speed like low, medium and high cool.
Defective switch may be mistaken as defective fan motor or
defective compressor if not checked properly. Below is the procedure in
testing selector switch.
Procedure:
1. Analyze table 1. You will use this as reference in checking the
selector switch.
2. Locate the common terminal of the selector switch. Usually the
common terminal of the selector switch has the label L1. If the
label has been erased, you can locate it by using an ohm meter
or continuity tester.
Switch
Position
Compressor
Motor
Fan Motor
High
Terminal
Med
Terminal
Low
Terminal
Off
0
0
0
0
Fan
0
0
1
0
Low cool
1
0
0
1
Medium
cool
1
0
1
0
High
cool
1
1
0
0
Common terminal is used as reference for this table
Legend: 0 – Open contact
1 – Closed
The common terminal will be the source line of compressor motor and
fan motor therefore it has a contact on the compressor terminal, low
Cool terminal when the selector is switched to low cool mode; it has a
contact on the compressor and medium terminal when the selector is
switched to medium cool mode; or it has a contact on or high cool
terminal every time the switches are activated (see table 1 for more
information).
3. Switch the selector to OFF mode. Then measure the continuity of the
terminals L1 - PL, L1 - 1, L1 - 4, L1 - 3 and L1 - 2. Based from the
chart on step 1, there is no closed contact on any of the terminals in
reference with common terminal when the selector is switched to OFF
mode.
4. Turn the selector switch to fan mode. Measure the continuity of all
Terminals in reference with the common terminal. Answer the table.
Turn the selector switch to low cool mode. Measure the continuity of
all terminals in reference with the common terminal. Answer the
table.
Turn the selector switch to medium cool mode. Measure the
continuity of All terminals in reference with the common terminal.
Answer the table.
Turn the selector switch to high cool mode. Measure the continuity of
all terminals in reference with the common terminal. Answer the
table.
Based on table 1. Analyze the result of your measurement (see table 2-6)
The common terminal is the terminal which have continues
connection when the selector is switched to low cool, medium cool and
high cool.
Low cool terminal is the terminal with connection every time the
selector is switched to low cool.
Medium cool is the terminal with connection every time the
selector is switched to medium cool.
High cool is the terminal with connection every time the selector is
switched to high cool
Assessment Method:
Demonstration, Evaluate Using Performance criteria checklist
Safety Reminders!
In performing this activity, you must practice
occupational health and safety procedures at all times.
Trainees
Name/Signature:
Trainer Signature: _________________________
Date:
Date : _____________
Performance Criteria Checklist
Task Sheet #2.4-3E
CRITERIA
YES
NO
Did I..
Located the rotary switch from the control panel
Removed the control panel cover
Used long nose pliers, to remove the female terminal of
rotary switch
Tested the rotary switch terminal for continuity test using a
multi-tester.
Demonstrated correct sequence in disassembling and
assembling of rotary switch
Observed housekeeping
Observed quality of work
Followed technical specifications from manufacturer’s
manual
Observed work safety
Comment/Feedback:
Trainees
Name/Signature:
Date:
Trainer Signature: _________________________ Date : _____________