Trouble Shooting - A.O. Smith GPS-75 Instruction Manual

trouBleshootInG GuIdelInes
Please check guidelines below. For your safety, water heater service should be performed only by a qualified service technician.
INTELLI-VENT TROUBLESHOOTING CHART - RESIDENTIAL CONTROL
# led status
a B c
6
a B c
7
a B c
8
a B c
9
a B c
10
a B c
11
a B c
12
a B c
13

trouBle shootInG

Read the GENERAL SAFETY INFORMATION section first.
proBleM
Ignition/flame failure.
The water heater has reached the
maximum number of retries and is
currently locked out for one hour.
Cycle the power to the water heater
off and on to reset.
service note:
The resistance (ohms) of a hot surface
ignitor will increase over time. If the
resistance at room temperature is near
18.8 ohms - consider replacing the ignitor
as a preventative measure.
Self diagnostic tests have found a problem 1. Turn the power off for 10-20 seconds then on again to
with the gas valve driver circuit, internal
microprocessor, or other internal circuits.
Flame signal has been sensed out of
proper sequence.
Water temperature in the tank has
exceeded 195°F (91°C) and has
activated the ECO.
The self diagnostic check detected one
or both of the temperature adjust buttons
are stuck.
The self diagnostic check has detected the
water temperature sensor (thermistor) is
either open or shorted.
1. Gas supply is turned off - pressure too low. Ensure
supply and manifold gas pressures are within
requirements in the installation manual. Manifold gas
pressure is non-adjustable if pressure is off by more
than 0.3" W.C. (75 Pa) replace the Intelli-Vent™ control.
2. Low supply voltage - should be 115 -125 VAC.
3. Ensure flame sensor is making good contact with the
burner flame, ensure flame is steady see #8 below.
4. Ensure the flame sensor is clean - use ultra fine steel
wool or Scotch-Brite™ pad to clean flame sensor.
5. Ensure the hot surface ignitor is positioned to provide
consistent ignition.
6. Check for any cracks in ignitor assembly ceramic
insulators - replace ignitor assembly if damaged.
7. Check resistance of ignitor at room temperature (77ºF)
(25°C) at the plug end. Replace ignitor if resistance is
not within 11.5 and 18.8 ohms at room temperature.
8. Ensure the correct size of vent pipe (2", 3", 4") was
used per installation manual for vent length. Using larger
pipe than required may cause excessive air turbulance
in the combustion chamber.
clear these error codes.
2. If any of these error codes persist or cannot be cleared-
replace the Intelli-Vent™ control.
1. Turn the power off for 10-20 seconds and then on again
again to clear this error code.
2. Replace the Intelli-Vent™ control if this error code persists.
1. Turn the power off for 10-20 seconds then on again
to clear this error code.
2. Replace the Intelli-Vent™ if the error code persists.
1. Press and release temperature adjust buttons. If the
above action does not clear the error, the control will
continue to regulate water temperature at the last setting.
However, settings will no longer be adjustable - the
control should be replaced.
1. Turn the power off for 10-20 seconds then on again
to clear this error code.
2. Replace the Intelli-Vent™ control if this error code persist.
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