Supply temp has risen too quickly
The 16 error code on Burnham boilers indicates supply temp has risen too quickly.
Burnham 16 means: supply temp has risen too quickly. The usual causes are inadequate boiler water flow or section of this manual. You can safely reset the boiler once — if 16 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does 16 Mean
The 16 code is shown by the boiler’s control board when it detects supply temp has risen too quickly. The boiler then stops instead of continuing to run in that condition: the code is the appliance reporting a problem, not proof that the boiler is broken.
| What you see on the boiler |
|---|
| The display shows 16 and the boiler stops until the fault is cleared |
Common Causes
Causes documented in the Burnham service literature published by usboiler.net, cross-checked against the manufacturer’s fault-code table.
| Cause |
|---|
| Inadequate boiler water flow |
| Section of this manual |
Safety Warning
16 involves electrical or pressure-related components. Do not attempt repairs without proper qualifications. Ensure the boiler is electrically isolated before any inspection. If you notice water leaks, unusual sounds, or pressure anomalies, contact a qualified heating engineer immediately.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
How to Fix It
See possible causes for “Hard Lockout 4”
Verify that circulation pump is operating and that circulation pump and piping are sized per
Refer to the Burnham service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Burnham models that can display fault code 16:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Burnham models | — | Possible |
Frequently Asked Questions
See possible causes for “Hard Lockout 4”. According to the technical documentation, this is the first check on the list for 16.
16 is not classified as a high-severity fault, so the boiler can be reset once. If 16 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.