Goodman GMV series - S-300 CHECKING PRIMARY LIMIT CONTROL

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SERVICING
S-300 CHECKING PRIMARY LIMIT CONTROL
All 80% and 90% furnaces use a nonadjustable, automatic
reset, bi-metal type limit control. Refer to the following draw-
ing for the location of the primary limit.
Location of Primary Limit
Primary Limit Control Location
(80% Upflow Furnace Shown, Counterflow Similar)
Style 1 drawing illustrates the Primary Limit used on the
80% furnaces.
Style 1
All 90% furnaces use a nonadjustable, automatic reset, bi-
metal type limit control. Refer to the following drawing for
location of the primary limit on the 90% furnaces.
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2
PRIMARY LIMIT
CONTROL
Primary Limit Control Location
(90% Upflow Furnace Shown, Counterflow Similar)
The following drawing illustrates the style of limit switches
used on the 90% furnaces.
ENCLOSED DISK
FRONT VIEW SIDE VIEW
Primary Limit Control Style
(90% Furnaces)
WARNING
HIGH VOLTAGE
D
ISCONNECT ALL POWER BEFORE SERVICING OR
CHANGING ANY ELECTRICAL WIRING.
MULTIPLE POWER
SOURCES MAY BE PRESENT.
FAILURE TO DO SO MAY CAUSE
PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
1. Remove burner compartment door to gain access to the
primary limit.
2. Remove low voltage wires at limit control terminals.
3. With an ohmmeter, test between these two terminals
as shown in the following drawing. The ohmmeter should
read continuous unless heat exchanger temperature is
above limit control setting. If not as above, replace the
control.