Viessmann error 74

The “Error 74” can mean many different things and we will try to cover many of the common ones.

The cuckoo, instead of shutting off the flame when reaching temperature, is causing overheating and sometimes emitting smoke as a result.

Insufficient information was found.

This hub helps you fix boiler error 74 for your Viessmann boiler.

Boiler Error 74 often comes with gas pressure check failure and vent solenoid failure. Boilers may also indicate a P641 error.

The two common issues here are gas pressure calibration failure and check gauge failure. With the values sent from the Landis+Gyr VT 10000-L monitors by serial protocol, this sensor is not able to properly calibrate the system data.

After some time, it will lead to pressure faults or vapor loss problems, which can be a prank to 10 pounds per square inch or over 150 pounds per square inch – an extensive scale problem as these are just some examples.

At this point, you need to have someone who properly understands what needs to be done with this code to maintain the boiler, or else there’s a risk that this could lead to dangerous situations like blackouts or even damage to the boiler itself beyond repair.