A.O. Smith BFM - 100, Installation & Service Manual

Page: 60 / 74

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Instruction manual BFM 60
11.4 Troubleshooting: No hot water
No hot water
Symptom Cause Solution Remark
No attempt to start
heating cycle
No supply voltage
present
1. Check if the isolator is ON.
2. Check whether there is power to the isolator
3. Check whether there is power to the electrical connector block
4. Check whether there is power to the burner control
5. Check fuse in the burner control
The measured voltage must be 230 VAC (-15%, +10%). See the BFM electrical diagram (14 "Electrical diagram")
If the error cannot be rectified, contact your installation engineer
No attempt to start
heating cycle (blocking
error)
Pressure switch not
closing
1. Blockage in the chimney flue or air supply
- Trace the blockage
- Remove the blockage
2. Defective pressure switch
- Check the wiring of the pressure switch
- Check that the pressure switch is working
Once the error is rectified, the appliance will automatically start up
if there is a heat demand
If the error cannot be resolved or is persistent, contact your
installation engineer
Failure in the
thermostat circuit
1. Check whether the control thermostat is switched (closed)
2. Check leads and sensors of the control and high-limit
thermostats
Repetitive starting of
the heating cycle
(cycling of the
appliance)
Too much resistance in
the chimney flue (the
pressure switch opens
during heating)
1. Check whether the chimney flue configuration (3.9 "Air supply
and flue") has been installed in accordance with instructions
If the error cannot be resolved or is persistent, contact your
installation engineer