© 2022 Staheli West
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Faults
Fault 208: Flue Temp Is High
Indicates flue temperature is above 600° F.
*Bad Flue temperature sensors can damage input cards and PLC’s. They can also cause max readings for all
inputs on card 1 on the PLC.
** If the PLC or input card are replaced before a possible faulty flue temp sensor is replaced, the faulty flue
temp sensor can damage the newly replaced components. (Replace components in order shown below).
*** Alarm can be disabled in Menu > Settings > Alarm Status > Flue Temp Alarm.
Causes
Troubleshooting
Fixes
• Soot has built up on tubes
causing high flue temperatures.
• If you don’t trust the flue
temperature reading on
the touch screen, confirm
temperature with infrared gun.
• Clean the tubes :)
• Faulty flue temp sensor.
• Confirm with an infrared gun
that the actual temperature is
not what is shown as the flue
temp reading on the touch
screen.
• Sudden spikes in flue temp
readings also indicate a faulty
flue temp sensor.
• Replace flue temp sensor.
• Faulty boiler rear door rope
gasket.
• Inspect the boiler rear door for
signs of heat damage where the
gasket may have failed. Too much
heat on the flue temp sensor
head can cause max readings.
• Repair/Replace boiler rear door
rope gasket.
• Faulty wiring.
• Inspect the wiring for ground,
continuity, and proper voltage.
• Replace/Repair wiring.
• Faulty input card 1 in the PLC.
• Perform “Test 13”.
• Replace faulty input card (See
“Test 13”).
• Faulty PLC.
• If after replacing the sensor and
the input card 1 there is still an
abnormal reading this indicates a
faulty PLC.
• Replace PLC.
• Scale has built up in the boiler.
• Remove a hand-hole cover and
inspect boiler tubes for scale.
• Use REDEW boiler de-scaler
(Part # 11194).
• Use Boiler Guard
(preventative).