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Technical Training Department ©2003
Ashland City, Tennessee
SBN TANK TYPE COMMERCIAL GAS WATER HEATER
SERVICE HANDBOOK
TEST 4 - UPPER TEMPERATURE PROBE CONTINUITY CHECK
Conditions:
Power On - Water below tempera-
ture set point.
Red, heater control “Reset Status”
LED-OFF
“Call For Heat” LED off.
TEST 4
Upper Temperature probe continuity check
Red wire to red wire - Turn supply power "Off" for this test
If… ...then
test indicates
no continuit
y
replace probe.
continuity
is indicated
probe should be okay (also verify Ohms
resistance for water temperature). (Reading will
be approximate.)
TEST 3
Continuity check of ECO (energy cut-off, high limit)
Black to Black wires of upper probe. Power is off.
If… ...then
continuity
is indicated
opens at 203° F; closes at 193° F. If water is
below 193° F, continuity is correct.
continuity
is not present
replace ECO sensor, if water temperature is
below 193° F.
water is less than 120° F
•
reset status LED should be on.
•
replace heater control if control will not manually
reset.
TEST 3 - CONTINUITY CHECK OF HIGH LIMIT (ECO)-CONTINUED
° F Ohms
70° 11,884
120° 3,759
140° 2,488
180° 1,169
Ohms Resistance Table