Page 84 - GRINNELL Mechanical Grooved Piping Products EMEA

Grooved Couplings
Valves and Accessories
CB800 Circuit Balancing Valves
Tech Data Sheet: G450
GRINNELL Model CB800 Circuit Balancing Valves are designed to achieve accurate and efficient balancing of hydronic heating or cooling systems. Circuit Balancing Valves provide superior accuracy in measuring flows rather than ball type circuit setters. The CB800 valve serves 5 functions:
• Throttling
• Measuring differential pressure
• Draining
• Filling
• Positive shutoff
These valves are rated at 20.7 Bar (300 psi) at 150°C (300°F). The Y-Pattern style provides low pressure drop. The globe style valve allows for precise throttling. The easy-to-adjust digital/vernier handwheel provides a minimum of 70 unique handwheel positions. The handwheel and test ports are located on one side for easy access. A built-in memory stop ensures the setting can be returned to a balanced position after shutoff. The self-sealing pressure/ temperature test ports use standard insertion probes to eliminate additional components.
The GRINNELL Circuit Balancing Valve is installed with flow in the direction of the arrow, and may be in the horizontal or vertical position. The handwheel can be positioned up or down, or on either side.
Material Specifications
Body
• Sizes 15 – 50mm ( 1⁄2" – 2") solder or BSP threaded connection: brass-resistant to dezincification (DZR)
• Sizes 65 – 300mm (2 1⁄2" – 12"), grooved or flanged connection: Cast Iron conforming to ASME ANSI B 16.5
Valve Stem and Disc
• Brass resistant to dezincification (DZR) O-Ring
• EPDM E
Handwheel
• Thermoplastic
For accessories and replacement parts contact a GRINNELL Sales Representative for details.
Valve Sizing
All balancing valves are sized to perform in a normal operation range between 25% and 100% of the full
open position, at a minimum differential pressure between 0.3 – 0.9m (1 – 3 ft.) of water. It is recommended that for improved accuracy, the valve is set to open 70%+.
1⁄2 2.6 - 4.2 3⁄4 3.4 - 6.2 1 6.2 - 9.6 11⁄4 9.4 - 21.0
11⁄2 15 - 30 2 22 - 42 21⁄2 39 - 106
76,1mm 39 - 106 3 60 - 132 4 100 - 217
139,7mm 112 - 317 5 112 - 317 165,1mm 220 - 437 6 220 - 437 8 223 - 881
10 292 - 1298 12 616 - 1731
Thread
Size
mm Inches
Flow Rate GPM LPM
Connection Type
15
0.687 - 1.110
20
0.898 - 1.638
25
1.638 - 2.536
32
2.483 - 5.548
40
3.96 - 7.93
50
5.812 - 11.096
65
10.30 - 28.01
65
10.30 - 28.01
80
15.85 - 34.87
100
26.42 - 57.33
125
29.59 - 83.75
125
29.59 - 83.75
Grooved
150
58.12 - 115.46
150
58.12 - 115.46
200
58.92 - 232.76
250
77.15 - 342.93
300
162.75 - 457.33
84
When maximum flow is known but a pressure drop through the balancing valve is unknown, select a balancing valve for a maximum pressure drop of 0.6m (2 ft.) water 0.06 Bar (0.8 psi) in the full open position as shown in the table to the right.
Accurate flow measurement requires that the velocity distribution near the balancing valve remains constant, regardless of the total flow through the pipe. Fittings, such as elbows and tees, disturb the normal flow profile which is established through straight pipe. Pumps create even greater disturbances. Failure to allow water flows around fittings and pumps to normalise can affect measuring accuracy by as much as 20% when the valve is in the fully open position. Minimum lengths (diameters, D) of straight pipe before and after the balancing valve prevent these errors.
Valves are designed for vertical, horizontal, or inclined installation.
Minimum Pipe Diameters from Fittings
3D 2D Pump 10D 2D