Ask the Expert – High Duct Static Cutout Switch

DPDT Low Differential Pressure Switches Series 1831

Question: Does Dwyer offer a differential pressure switch with manual reset for high duct static cutout applications?

Answer: For high duct static cutout applications, Dwyer recommends our Series 1831 DPDT Low Differential Pressure Switches with Manual Reset.  The Series 1831 is purely mechanical, requiring no power to operate the DPDT switch, and can be set in the field using the easily accessible set point adjustment screw.  Furthermore, the Series 1831 eliminates common problems associated with typical high duct static cutout installations.  Since the 1831 requires absolutely no power to drive its outputs, a separate power loop and its associated additional wiring and conduit is alleviated, reducing material and labor installation costs.  Both control contacts of the Series 1831 activate at the same time.  The potential of the lead switch shutting down the fan preventing the lag switch from sending an alarming signal to the DDC is no longer a probable system liability.  Potential costly maintenance calls are diminished.  Unlike typical switches that possess only a single conduit entry for both control loops, the Series 1831 provides two conduit connections simplifying wiring while eliminating additional conduit tees.  The Series 1831’s specifications and features make it the superior choice for high duct static cutout applications.