E777 🟡 Repair Required
Navien Error Code E777: System Error Code
⚠️ Your Navien boiler has encountered a system error. It's safe to operate, but needs professional attention.
How to Fix Navien Code E777
- Check if the remote control is properly paired with the boiler. Try removing and re-adding it.
- Ensure there are no other electronic devices nearby that could be causing interference.
- If the issue persists, contact a professional HVAC technician for repair.
What Does Navien Error Code E777 Mean?
The Navien E777 error code indicates a communication issue between your boiler's main board and the remote control. This isn't an immediate safety concern, but it will prevent you from using the remote to control your boiler. The boiler will continue to function normally using the local controls.
Common Causes of Navien Code E777
- Damaged or disconnected wiring between the main board and remote control
- Faulty main board or remote control
- Interference from other electronic devices
Applicable Navien Models
Source Documentation
This error code is documented in 5 official Navien technical manuals.
NFB-H Installation & Operation ManualPage 116
ReasonLow Water Cutoff Activated
ActionCheck supply water.
Navien NCB-H Installation & Operation ManualPage 130
ReasonLow Water Cutoff Activated
Action● Check the LWCO wiring connection. ● Ensure that the system water level is appropriate. ● Add make-up water to the system if necessary.
Navien NFB-H Installation & Operation ManualPage 116
ReasonLow Water Cutoff Activated
ActionCheck supply water.
Navien NFC-H Installation & Operation ManualPage 128
ReasonAbnormal operation: LWCO limit (external device)
ActionAuto RESET
Navien NHB-H Installation & Operation ManualPage 119
ReasonLow Water Cutoff Activated
ActionCheck supply water.
Need a Pro to Fix Navien Code E777?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Navien Tankless Water Heater Code E777
Main Board OEM: NAVIEN-00123456
Remote Control OEM: NAVIEN-6543210