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Troubleshooting
35
Error lock-out is indicated by the orange LCD blinking. An error lock-out is done for safety reasons. After fixing the
problem, press the reset button to return the heater to service.
AA Flow reduced • 1. Check heat exchanger - flush or
descale if necessary.
LED or LCD of the appliance doesn't
start up, no function.
No voltage supply, fuse blown,
transformer etc. defect
• 1. Check voltage supply
• 2. Check fuse
• 3. Check control unit
1)
.
Noise; boiling noise (over heating). Low circulation, air inside installation,
bad heat transfer.
• 1. Check for air in system, purge if
detected
• 2. Check circulators for proper oper-
ation
• 3. Check heat exchanger for block-
age or scale deposits
• 4. Check gas type, injectors, gas
valve
• 5. Verify heater is not in service
mode.
No heating function. No heat demand by the thermostat,
thermostat set too low, other defect.
• 1. Check thermostat position
• 2. Check control unit
1)
.
No DHW function. No heat demand by the 12kohm
thermistor or aquastat.
• 1. Check thermistor cable
• 2. Check Domestic hot water
thermistor or aquastat on tank
• 3. Check control unit
1)
.
1) Check connections, fuse or if there are visible damages.
Fault Indication Possible Cause Check
Table 18
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