Velocity K2WTC-135, Инструкция по установке, эксплуатации и обслуживанию

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IX. System Piping
(continued)
Count all fittings in the boiler loop (shaded in Figure 9.5):
4 90° Elbows
2 Turn in Tee
2 Isolation Valves
Note: Unions, Secondary Connection Tees, and factory supplied fittings are ignored.
Calculate total equivalent length from Table 9.3:
20 ft Straight Pipe + 4 Elbows x 2.8 + 2 Turn in Tee x 5.5 + 2 Valves x 0.7 = 43.6 Equivalent Feet
Since the total equivalent length is less than 60 ft, flow through boiler loop meets requirements in Table 9.1.
3. Hydraulic Separators – Hydraulic separators serve the same purpose as the closely spaced tees connecting
the boiler and system loops in Figure 9.2. They also generally provide effective connection points for
automatic air elimination devices and an expansion tank. These separators are available from several
sources and may be used in place of the closely spaced tees shown in Figure 9.2. When a hydraulic
separator is used in place of the tees, the 60 ft equivalent length limitation still applies. Select a hydraulic
separator having 1” or larger boiler connections that is designed for the boiler flow rates shown in Table 9.1.
(May Be Used for Copper or Threaded Fittings)
Fitting Pipe Size Equivalent Length (ft)
90° Elbow 1” 2.8
45° Elbow 1” 1.4
90° Turn in Tee 1” 5.5
Run of Tee 1” 1.8
Gate Valve (Open) 1” 0.7
Full Port Ball Valve 1” 0.7
Y-Strainer* 1” 7.0
Boiler Model
Approx. Flow
(GPM)
Approx. Rise (°F)
Boiler Model
Approx. Flow
(GPM)
Approx. Rise
(°F)
135 8.6 25 135 8.3 26
150 11.8 23 150 11.1 24
180 11.8 28 180 11.1 29
Table 9.4a: Flow Available with Boiler Loop
Equivalent Length of 30 ft or Less
Table 9.4b: Flow Available with Boiler Loop
Equivalent Length of 60 ft or Less
Table 9.3: Equivalent Lengths for Selected Valves and Fittings
* Based on Cv of 20. Pressure drop through strainers varies widely. 7 ft equiv-
alent length may be assumed for strainers having a published Cv greater than
20.