Dry Sprinkler Inspection

A dry sprinkler system is pressurized with air or nitrogen, rather than having the pipes constantly filled with water. These systems often cover unheated spaces like freezers, attics, or an outdoor loading dock.

The main control valve and riser are usually located in a heated space such as a maintenance room, or closet. The pressurized dry-pipe valve prevents water from entering the system until a fire activates one or more sprinkler heads.

Once a sprinkler head breaks, the system loses air pressure and the dry valve activates. The clapper then opens, filling the system with water which makes its way to activated sprinkler heads to contain and/or suppress the fire until emergency services can arrive on scene.

[robertobryk]

Why do you disassemble the valve _after_ testing its function? This way there's no opportunity to notice that the reassembly is incorrect in a way that reduces flow.

[dicko-]

you had residual and static water pressures backwards.
Static is no flow.
Residual is 2" drain test water flow.

[gerald]

is there a way I can test the water flow switch without tripping the Dry Valve? thanks..