Thermostats - Maytag 111990" Automatic Dryers Service Manual

THERMOSTATS
THERMOSTATS
There are three different kinds of ther-
mostats in these dryers.
1. Bi-Metal
type~
2. Resistance type (Multi-temperature).
3. Thermal Fuse type.
All react essentially to temperature with
direct effect on heat on or heat off func-
tions of a dryer.
To remove those located on blower
cover:
1. Remove 2 screws from Front Panel
and swing panel out.
2. Remove wires from thermostat.
3. Remove screws securing thermostat
to cover.
160 0 THERMOSTAT - Microprocessor
Models
Bi-Metal Type
The 160° thermostat functions as a back
up to the thermistor. It is mounted on
the blower cover. The thermistor, in
conjunction with the microprocessor
boar~ and heater relay, is used to
control the cycling of the temperature
between 135°F and 155°F. The 160°
thermostat is placed in series with the
gas valve I heating element and will
open the heat circuit in the event the
thermistor fails to open the circuit at
temperatures above 155°F.
ED/GD401 1090
To remove the 160 0 thermostat:
1. Disconnect power supply.
2. Remove front panel.
3. Remove the thermostat cover
mounted to the base (electric dryer
only).
4. Disconnect wires from the thermo-
stat.
5. Remove the two screws securing the
thermostat to the blower cover.
To check the 160 0 thermostat:
CAUTION - - - - - - - - - - ,
Always disconnect power supply
before making continuity or resist-
ance checks.
Check for continuity across thermostat
at room temperature. Attach meter
across terminals BK and PU. No conti-
nuity, replace.
THERMISTOR - Microprocessor Models
Resistance Type
The thermistor is a semiconductor
device (solid state) that has a negative
temperature coefficient of resistance;
its resistance decreases as its temper-
ature increases and vice versa. The
thermistor functions as the "sensing
control" for the dryer's heat circuit. No..
cycling thermostat is used. It is
mounted on the blower cover and is
SECTION 3. SERVICE PROCEDURES
3-24