Low Information
S.97 on Vaillant ecoTEC Pro 24

Your boiler is performing a routine internal check on its water pressure sensor and should resume normal operation once finished.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Water pressure sensor self-test. The self-test for the water pressure sensor is activated.

What causes this fault?

This occurs when the boiler's internal computer performs a safety check to ensure it is receiving an accurate reading from the water pressure sensor. It happens automatically to verify that the system is not running dry, which protects the internal components from overheating. Most often, this is just a momentary pause in operation, but if it persists, it may indicate the sensor is sending inconsistent signals or the wiring has become loose.

DIY fix possible

Wait up to 15 minutes for the automated test to completeCheck if the water pressure is between 1.0 and 2.0 barReset the boiler if the code remains on the screen for a prolonged period

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