Manual Valves
There are a number of manual valves required for
the system to operate properly and safely. These
valves are used as shut off valves, drain valves
and throttling valves. They can be globe, gate,
ball or balancing type valves.
The
globe valve
can be used as a shut off, drain
or throttling valve. Even in the open position, the
valve is fairly restrictive to flow. It has a much
greater equivalent length (resistance) than the
other types of valves.
The
gate valve
can be used as a shut off or drain
valve. When in the open position, there is very
little resistance to flow. Gate valves have a
greater susceptibility to chatter (noise) and
malfunction with age. Gate valves tend to be less
expensive than the other type of valves.
The
ball valve
can be used as a shut off or drain
valve but not a throttling (balancing) valve. When
in the open position, a full bore ball valve has
very little resistance to flow, and these valves
tend to be both the least expensive and the
least susceptible to seizing over time. Do not
use reduced bore ball valves as they are very
restrictive to water flow.
The
balancing valve
can be used as a throttling
valve. It can make small flow changes easily and
has lower resistance than a globe valve. This
valve will be considerable more expensive.
7
Balance Valve
Ball Valve
Globe Valve
Gate Valve
