Monthly Archives: September 2026

CAREL has discontinued the pLDPRO display family, with supply ending in mid 2026. For most HVAC applications, the pGDn is the recommended replacement: PGD1000F01 without buzzer or PGD1000FZ1 with buzzer. It is electrically and functionally equivalent, but slightly larger, so check the panel cut out first.

Choose a spring return actuator wherever a valve or damper must move to a safe, fail safe position if power is lost, and choose a non spring return actuator wherever that fail position genuinely does not matter. Getting this choice wrong on a safety critical application, such as a fire damper, is one of the most common specification errors engineers make.

Differential pressure switches work on the principle of measuring the difference in pressure at two ends and then generating an electrical signal when this difference exceeds a certain limit. It is used in HVAC applications for detecting a clogged filter, for verifying that the fan is working, and for ensuring flow through a pump.

A PT100 temperature detector is a resistance temperature detector that consists of platinum with a resistance of 100 ohms at zero degrees Celsius and exhibits predictable changes in resistance with changes in temperature. PT100 temperature detectors are among the most accurate means of temperature measurement.