Navien boiler error E016

What causes E016

Poor circulation or a blocked heat exchanger.

What to do

Turn the boiler off and let it cool. The pump and heat exchanger need checking.

Can I fix it myself?

No. This is a fault a technician should handle; keep using the appliance and it can get worse or become unsafe.

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.