Test Procedures; Oven Thermostat; Selector Switch - Amana AO27DG Service Manual

Test Procedures

!
WARNING

Oven Thermostat

The oven thermostat maintains correct oven tempera-
tures in bake, broil and self-clean operations.
In manual and timed bake operations, thermostat con-
tacts 7-8, C-BA and 1-2 close completing the bake cir-
cuit through the clock in a timed bake operation, the
selector switch, bake ignitor and bake gas valve to
neutral. Thermostat contacts 1-2 are the cycling con-
tacts that maintain correct oven temperatures.
In manual or timed bake operations, thermostat con-
tacts 7-8, C-BR and 1-2 close completing the bake cir-
cuit through the clock in a timed bake operation, the
selector switch, oven ignitor and oven gas valve to
neutral. Thermostat contacts 1-2 are the cycling con-
tacts that maintain correct baking temperatures.
In the self-clean function with oven temperatures be-
low approximately 650 to 700 degrees F, thermostat
contacts COM-NO and 1-2 close completing the clean
circuit through the sail switches, selector switch, rear
latch switch, self-clean relay, broil ignitor and broil gas
valve to neutral.
After the oven reaches approximately 650 to 700 de-
grees F, thermostat contacts COM-NO open and
COM-NC close now completing the circuit through the
sail switch, selector switch, top latch switch, self-clean
relay, bake ignitor and bake gas valve to neutral. Con-
tacts 1-2 cycle to maintain correct self-cleaning tem-
peratures.
Use the following procedure to check thermostat conti-
nuity.
1. Disconnect power to oven. Remove thermostat
wiring.
2. Access thermostat contacts by removing control
panel glass and control panel mounting brackets.
3. Set ohmmeter to the low ohm range. Follow ther-
mostat contact chart as shown in the figure below.
Thermostat Contacts
Dial 1-2 COM N.O. COM N.C.
Off N.S. O
Bake Cycles N.S.
Broil Cycles X
X Below
Clean Cycles
700°
O = Open
Circuit
Thermostat Contact Chart
RA233001 Rev. 3
To avoid the risk of electric shock, personal injury or death, disconnect power To avoid the risk of electric shock, personal injury or death, disconnect power To avoid the risk of electric shock, personal injury or death, disconnect power
To avoid the risk of electric shock, personal injury or death, disconnect power To avoid the risk of electric shock, personal injury or death, disconnect power
before servicing, unless testing requires it. before servicing, unless testing requires it. before servicing, unless testing requires it. before servicing, unless testing requires it. before servicing, unless testing requires it.
C-BR C-BA
X O O
N.S. O X
O X O
X Above
O X
700°
X =
N.S.=Not
Closed
Specified
Circuit
4. Replace thermostat if contacts fail.
Thermostat – Front View
Thermostat – Back View
7-8
O
X
X
O
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