Siemens Building Technology QFM81.21 Hygrostat 326058-756 High-Grade Construction: Manufactured with materials

High-Grade Construction: Manufactured with materials resistant to copper-to-brass brazing stress and internal mechanical wear

but specifies rotation can often be adjusted via lead reversal depending on the specific wiring diagram

As a pilot-operated diaphragm valve

it is specifically a time-delay model

verifying that exhaust gases are safely vented before the ignition sequence begins

Siemens Building Technology QFM81.21 Hygrostat 326058-756 High-Grade Construction: Manufactured with materialsThe Siemens Building Technology QFM81. 21 is a commercial grade duct hygrostat designed for precision relative humidity control in HVAC systems. Engineered for both monitoring and regulation, this device features a stabilized sensing strip that ensures superior linearity and long term stability, even in high humidity environments or air contaminated with dust. Unlike baseline models, the QFM81. 21 utilizes an internal setpoint adjuster to prevent