If you hear a loud grinding or vibrating noise

With a 330Vac rating

this proportional damper actuator is specifically designed for use in multi-zone

where electrical resistance varies inversely with temperature changes

Built with a corrosion-resistant housing and a high-tolerance diaphragm

Danfoss 193B-1506 Valve 320735-701 If you hear a loudThe Danfoss 193B 1506 is a high performance ESBE VRG130 series rotary mixing valve designed for precise temperature regulation in demanding HVACR applications. Engineered with a 1 1 2" FNPT threaded connection and a substantial 29. 3 Cv flow coefficient, this 3 way valve is ideal for hydronic heating systems and chilled water circuits where high flow capacity and minimal pressure drop are critical. The body is constructed from DZR brass