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Navien boiler error E351
Automatic fill fault. The make-up water valve could not bring the pressure up.
Moderate · you can check this yourself
E351
Meaning: Automatic fill fault
What causes E351
The make-up water valve could not bring the pressure up.
What to do
Check the water supply to the boiler is open. If it returns, call a technician.
Can I fix it myself?
Often, yes. Try the check below first — it costs nothing and frequently clears the code.
If the code comes back
Book a visit and add the code to the booking. A technician arrives knowing which parts to bring, diagnoses the boiler for a flat $89 and gives you an exact quote before doing any work.
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