How to Program a Switch for Manual Reset

Compact Low Differential Pressure Switch with Manual Reset, Series 1900MR

Several applications require manual reset switches, which are switches that need to be physically reset by an individual for a process to continue or restart. A manual reset is often needed when an area has to be inspected prior to equipment restart. This can help to ensure the safety/inspection of both equipment and other individuals in the area.

Some switches have a mechanical manual reset (such as the Dwyer Series 1900, 1831, and 1800). However, there may be a need to have a manual reset for applications beyond what these switches are designed for. If a pump is allowed to run with a clogged filter, for example, this may severely damage the pump. Continue reading “How to Program a Switch for Manual Reset”

Proving Water Flow in Rooftop Air Handlers

We met with an original equipment manufacturer (OEM) last year, who was working on a new design for rooftop air handling equipment. Part of the their design utilized water flow for cooling in a loop.

Low or no-flow conditions can cause major damage to expensive pumps, motors, and other equipment, which could result in extensive downtime and repair costs. In order to prevent this, the customer needed an inexpensive, but reliable and robust method for proving water flow. Continue reading “Proving Water Flow in Rooftop Air Handlers”

Thermal Dispersion Flow Switches

Thermal Dispersion Flow Switch, Series TDFS2

Dwyer Instruments, Inc. offers several flow measuring products that use a thermal sensing element.

Thermal dispersion flow sensors use a temperature element that is heated up beyond the media temperature. Based on calorimetry, the flow moving past the sensor will have a cooling effect that is directly proportional to the flow velocity. The heat is convected from the heated probe surface to the boundary layer of the fluid flowing over the heated surface. Continue reading “Thermal Dispersion Flow Switches”