Boiler temperature sensor reached High Temp Limit setting (no higher than 200° F)
The HIGH TEMP LIMIT error code on Weil-Mclain boilers indicates boiler temperature sensor reached high temp limit setting (no higher than 200° f).
Weil-Mclain HIGH TEMP LIMIT means: boiler temperature sensor reached high temp limit setting (no higher than 200° f). On this component the documented failure modes are boiler temperature sensor reached high temp limit setting, the temperature sensor has failed — short circuit or open circuit or wiring, connector or harness of the temperature sensor damaged or loose. You can safely reset the boiler once — if HIGH TEMP LIMIT returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does HIGH TEMP LIMIT Mean
The HIGH TEMP LIMIT code is shown by the boiler’s control board when it detects boiler temperature sensor reached high temp limit setting (no higher than 200° f). 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 HIGH TEMP LIMIT and the boiler stops until the fault is cleared |
Common Causes
The first cause below is the one the Weil-Mclain service literature publishes for this code (source: weil-mclain.com). The others are the failure modes documented for the same component on other boilers, confirmed by 13 different manufacturers.
| Cause |
|---|
| Boiler temperature sensor reached High Temp Limit setting |
| The temperature sensor has failed — short circuit or open circuit |
| Wiring, connector or harness of the temperature sensor damaged or loose |
| Flue or air intake blocked or restricted |
| Heat exchanger fouled or partially blocked |
Safety Warning
HIGH TEMP LIMIT 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
Verify that high limit setting is at least 10° F above the maximum target temperature plus the off differential
Verify all isolation valves are open and circulators are programmed into the control properly. The boiler circulation pump output and System Pump/Aux. output can be configured to turn on or off with each priority. Refer to the Control Setup section to configure these properly for the system
Verify water pipe is installed correctly per instructions in this manual
Verify proper circulation pump sizing for boiler size and system requirements
See message displayed TEMPERATURE SENSOR and foll
Measure the resistance of the temperature sensor with a multimeter and compare it against the manufacturer’s resistance-versus-temperature table; replace it if it is open circuit, short circuit or out of range.
Refer to the Weil-Mclain service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Weil-Mclain models that can display fault code HIGH TEMP LIMIT:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Weil-Mclain models | — | Possible |
Frequently Asked Questions
Verify that high limit setting is at least 10° F above the maximum target temperature plus the off differential. According to the technical documentation, this is the first check on the list for HIGH TEMP LIMIT.
HIGH TEMP LIMIT is not classified as a high-severity fault, so the boiler can be reset once. If HIGH TEMP LIMIT comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.