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Brass float air vent with transparent top, male inlet connection

Watts

Watts FV-4-1/8 Air Vent Brass 150 psi 240F

SKU CH-1MSN-1QYQT

Brass float-type air vent handles water and glycol systems up to 240 °F and 150 psi

  • ColorTransparent
  • Automatic air release with float-type vent mechanism
  • Brass body rated for 150 psi working pressure
  • Operates up to 240 °F in glycol systems
  • Opens at 33 °F minimum temperature
  • Polyethylene float with silicon rubber gasket seal

Watts Brass Air Vent

The Watts FV-4-1/8 is a brass float-type air vent designed for glycol systems handling water media. It operates at a maximum pressure of 150 psi and a maximum temperature of 240 degrees Fahrenheit. The unit features a male inlet port and a polyethylene float with a silicon rubber gasket.

Replaces basic manual vents

This automatic vent eliminates the need for manual air bleeding in hydronic or glycol loops. The upgrade is worth it when a system traps air that reduces heat transfer or causes noise. It provides continuous venting without operator intervention.

Handles 2 lb/hr condensate

The float mechanism vents air at a condensate capacity of 2 lb/hr, suitable for typical residential and light commercial loops. It will not keep up with high-volume steam mains or rapid-fill scenarios that exceed this rate. Minimum operating temperature is 33 degrees Fahrenheit.

Highlights

  • Automatic air release with float-type vent mechanism
  • Brass body rated for 150 psi working pressure
  • Operates up to 240 °F in glycol systems
  • Opens at 33 °F minimum temperature
  • Polyethylene float with silicon rubber gasket seal

Specifications

ColorTransparent
BrandWATTS

Questions about this item

What thread size does the male inlet port on this Watts air vent require for mounting?

The vent has a male inlet port; match the mating fitting to the port's thread specification for a proper seal.

How is the float-type vent installed, and what common step is missed?

Install the vent upright so the polyethylene float can move freely; the step often missed is verifying the silicon rubber gasket seats fully before tightening.

What maintenance will the float and gasket need over time?

Inspect the polyethylene float and silicon rubber gasket periodically; replace either component if the float sticks or the gasket shows cracking or leakage.

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