Brochure

6
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.
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.
Correction For Liquids
Applies to liquids other than water. Correct the measured flow (q)
by the density ( ) according to this formula.
Sizing a Balancing Valve
When the differential pressure and design flow are known, use this
formula to calculate Cv value. The Macon Balancing pressure drop
tables on pages 8 to 10 can also be used.
Figure 3
Actual Flow =
q
CBI
p
p
C
v
= 1.52
q
q in GPM, p in Ft. of H2O
C
v
=
q
q in GPM, p in PSI
6
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.
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.
Correction For Liquids
Applies to liquids other than water. Correct the measured flow (q)
by the density ( ) according to this formula.
Sizing a Balancing Valve
When the differential pressure and design flow are known, use this
formula to calculate Cv value. The Macon Balancing pressure drop
tables on pages 8 to 10 can also be used.
Figure 3
Actual Flow =
q
CBI
p
p
C
v
= 1.52
q
q in GPM, p in Ft. of H2O
C
v
=
q
q in GPM, p in PSI
16
14
12
10
8
6
4
2
1 2 3 4 5 6 7 8 9 10
Deviation +/%
Pre setting