Navien Error Code Sys Supply Temp: Status Information item 8 – Sys Supply Temp (Boiler)

Updated October 16, 2026 · by Aurora Star Tech Inc.

Navien error code Sys Supply Temp on a boiler means: Status Information item 8 - Sys Supply Temp. It is also called Navien diagnostic code Sys Supply Temp.

Low severityBoilerAlso Combi BoilerNavien NHB-H

Homeowner? What Navien code Sys Supply Temp means for you

Usually minor Your boiler is reporting: Status Information item 8 - Sys Supply Temp. This code is usually informational or minor. The safe checks below often clear it; call us if it keeps showing up.

Safe things you can check yourself

Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
Look at the pressure gauge on the boiler. If it reads much lower than usual or near zero, or water is leaking, call a technician.
Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
Check that the boiler gas valve is open (handle in line with the pipe).
Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Navien error code Sys Supply Temp mean?

System supply temperature (F). Read-only item 8 in the Status Information menu.

Applies to: NHB-055H, NHB-080H, NHB-110H, NHB-150H

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Navien models that use code Sys Supply Temp

NHB-055H NHB-080H NHB-110H NHB-150H

Other Navien Boiler codes

Code	Meaning
Space heating demand icon	Space heating demand
Space heating temperature	Space heating temperature display
Status Information	Status Information menu
Supply Limit - No. of Times	EMS Data counter 9
Supply Temp	Status Information item 6 - Supply Temp
Sys Return Temp	Status Information item 9 - Sys Return Temp
system/Zone3 Pump Status	Input/Output Status item 8 - system/Zone3 Pump Status
System check icon	System check or error needed
System pressure	System pressure display
Tank Sensor Temp	Status Information item 13 - Tank Sensor Temp
Water Press	Status Information item 14 - Water Press
Zone2 Pump Status	Input/Output Status item 7 - Zone2 Pump Status

All Navien Boiler error codes →

Navien code Sys Supply Temp: homeowner questions

What does Navien code Sys Supply Temp mean?

Status Information item 8 - Sys Supply Temp. System supply temperature (F). Read-only item 8 in the Status Information menu.

Is it safe to keep using my boiler with code Sys Supply Temp?

Usually yes. Code Sys Supply Temp is normally minor, but if it keeps coming back have it checked.

Can I reset Navien code Sys Supply Temp myself?

You can try one reset (power off for 30 seconds, then on). If Navien code Sys Supply Temp comes back, the cause is still there and a licensed technician should check it.

Who can fix Navien code Sys Supply Temp near me?

Aurora Star Tech Inc. repairs Navien boilers in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Boiler Not Heating: What to Check

Troubleshooting guides

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Source: Navien NHB-H User's Information Manual (V1.0 Apr 2024), 3.3, p.13-14; Navien NHB-H Installation and Operation Manual, 11.7, p.103-104. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.