Import Fixed Set Point Differential Pressure Flow — Buy in Bulk from Supplier in China

The Fixed set point differential pressure flow switch from Acol (Shanghai) Online Controls Co., Ltd. is a mechanical device designed to monitor liquid flow in HVAC, plumbing, and heat exchanger systems by detecting pressure differentials across a flow path. The model WFS10004AA activates a dry contact relay when the pressure difference reaches a preset threshold of 4 kPa, signaling flow presence or absence without requiring external power.

The switch uses a diaphragm and spring mechanism calibrated to respond to pressure changes between 0 and 5 bar differential, with a hysteresis of 1.2 kPa to prevent relay chatter. It operates within a media temperature range of -20°C to 93°C and can withstand a maximum static pressure of 10 bar. The SPDT contact is rated for 10A at 250V AC, suitable for direct control of pumps or valves. The housing is made of corrosion-resistant polymer, typical for inline flow switches in commercial water systems.

This device is commonly used in plate and shell-and-tube heat exchangers to prevent frost damage or efficiency loss due to low flow. Buyers include OEMs of HVAC equipment, industrial boiler manufacturers, and building automation integrators. The unit is supplied as a single piece with 13 cm x 10 cm x 11 cm dimensions and weighs 0.65 kg. Trade terms are typically EXW Shanghai or FOB Shanghai, with lead times of 2 to 3 weeks. Packaging is in retail boxes with ESD protection for sensitive electronics.

Acol (Shanghai) Online Controls Co., Ltd. is based in Shanghai, China, and specializes in flow and pressure control devices for OEM applications. The company does not publish its history, employee count, or annual production volume. The listing confirms manufacturing capability through detailed technical documentation and product model numbering consistent with industrial control standards. No certifications such as ISO 9001 or CE are mentioned.

The supplier is classified as 'imported' and 'harbor' tier, indicating past export activity but no verified buyer feedback or response metrics on the platform. The listing includes application-specific use cases for heat exchangers and pump monitoring, suggesting engineering focus rather than broad retail distribution. Buyers should request test reports for set point accuracy and contact endurance under load before committing to bulk orders.