Installation & Flow

Installation Recommendations
Install the valve in the correct flow direction according to the arrow on the valve body and the distance parameters detailed in Figure 1 (Note: D = pipe diameter).

For Series STVL, cover the valve body with a wet cloth when soldering to prevent premature deterioration of valve components.

When used with a pump, it is recommended to use a straight length of pipe totaling 10 x D (instead of 5 x D) upstream or downstream to avoid turbulence that will affect the measuring accuracy. See Figure 2.

Turbulence can influence the measurements by up to 20% if this recommendation is not followed.

Flow Measurement & Accuracy
The measuring instrument connects to the test ports of the valve and is pre-programmed
with Macon Balancing characteristics. The pressure drop and flow readings can be read off the display. If access to a Macon Balancing instrument is unavailable, other industry standard models are compatible. In addition, the flow can be determined using the pressure drop diagram that is included in the operating instructions with each Macon Balancing valve.

The accuracy is highest when the valve is fully open. Therefore, it is recommended to choose a valve that can be opened at least three turns at the calculated pre-setting value. Figure 3 represents the flow measurement deviation in relation to handwheel turns.

Typical Specification
All balancing valves shall be of one manufacturer.

Furnish and install, as shown on job plans and in accordance with manufacturers installation instructions, Macon Balancing Valves, Series STVL/STV/STVA/STVC. Valves are to be of “Y” pattern globe style design and perform the following functions: a) Flow balancing, b) Flow measurement, c) Positive shut-off.

All balancing valves must have a minimum ten (10) turn, 360o handwheel with digital and vernier scale readout for precise setting. Balancing handwheel must include a memory stop and locking feature to prevent tampering after pre-setting.

All balancing valves shall have self-sealing ports for measurement of differential pressure and fluid temperature using standard pressure and temperature test probes. Test ports shall be located at a 45o offsetting angle and be removable for implementation of optional drain kits where required.

All balancing valves in sizes 1/2″ (DN 15) through 2″ (DN 50) shall be made of dezincification resistant brass and have either sweat or NPT thread connections. Valve body sizes 2 1/2″ (DN 65) through 12″ (DN 300) shall be made of cast iron and flanged to 125lb standard.

All balancing valves shall be manufactured by the company complying with international quality standard ISO 9001.