Hand Valve

The HV series is a brass hand valve for manual isolation on refrigerant lines. The red hand wheel gives a clear visual indication of position, and the valve is used wherever a line has to be shut by hand: on the liquid and suction lines of a condensing unit, either side of a filter drier, on each branch of a manifold, and at the inlet to a pump-circulation package.

Flare versions run from HV-02 to HV-07, covering 1/4 inch to 7/8 inch SAE with threads from 7/16 inch to 1-1/4 inch; solder versions HV-02H to HV-06H cover 1/4 inch to 3/4 inch copper tube. The flare version is the practical choice for field work where a line has to be opened repeatedly, while the solder version is used on factory-built equipment.

The body is brass with a screwed stem and packing, and the seat isolates against full system pressure in either direction. Because it is a manual valve it is normally left fully open or fully closed rather than used for regulation - throttling a hand valve erodes the seat and makes it leak when it is eventually closed.

Selection is by line size; the pressure drop of a correctly sized hand valve is small compared with a solenoid or a filter drier, so there is no capacity table to work through.

Practical points: fit the valve where the hand wheel can be reached without dismantling pipework, especially on ceiling-mounted units; back-seat the stem after opening to protect the packing; and when brazing, wrap the body and leave the valve half open so expanding gas can escape rather than pushing past the packing.