Valve Selection - Honeywell W180 User Manual

W180 ZONE CONTROL SYSTEM
Using the graph in Fig. 5, find the maximum valve operat-
ing temperature as follows (to find maximum ambient
temperature for a valve when fluid temperature is known,
reverse this procedure):
a. Measure ambient temperature at the valve and
locate this temperature on the ambient tempera-
ture scale on the graph.
b. Draw a line from this ambient temperature, paral-
lel with the fluid temperature scale, to the maxi-
mum fluid temperature line.
c. Draw a line from this point down to the fluid
temperature scale to find maximum operating
temperature. (Note the example, shown by the
dashed line, in Fig. 54.)
4. Size the expansion tank.
5. Determine the elbow equivalents.
6. Determine the pipe flow resistances.
7. Determine the valve pressure drop. The pressure
drop in psi [kPa], equivalent feet [meters] of pipe, or feet of
water [kPa] can be calculated from Figs. 55 through 60 as
follows:
a. Calculate the flow rate needed to heat the zone.
b. Determine the Cv [kV] rating of the motorized
valve.
c. Select the graph corresponding to the Cv [kV]
rating (Figs. 55 through 60).
d. Determine pressure drop across valve using pro-
cedure 1), 2), or 3).
1) Pressure drop in psi [kPa].
a) Locate the flow rate at the bottom of graph.
Fig. 54—Maximum temperature characteristics of valves with Class F motors.
210
[99]
200
[93]
190
[88]
180
[82]
170
[77]
160
[71]
150
[66]
140
[60]
130
[54]
120
[49]
110
[43]
100
[38]
90
[32]
80
[27]
DEGREES F
DEGREES C
68-0139
MAXIMUM AMBIENT
TEMPERATURE LINE
O O
EXAMPLE: 150 F [66 C] IS THE AMBIENT TEMPERATURE AT THE VALVE,
O O
235 F [113 C] IS MAXIMUM FLUID TEMPERATURE.
70 80 90 100 130
110 120
[21] [27] [32] [38] [43] [49] [54]
b) Draw a line upward from the flow rate to the
intersection of the curve.
c) Draw a line from the curve intersection to
the left edge of the graph to determine
pressure drop in psi [kPa].
2) Pressure drop in equivalent ft [m] of pipe.
NOTE: Both 1/2 and 3/4 in. pipe conversion
scales are available for this determination.
a) Locate the flow rate at the bottom of graph.
b) Draw a line vertically to top of the graph.
Determine pressure drop for either 1/2 or 3/4
in. pipe.
3) Pressure drop in ft of water [kPa].
a) Locate the flow rate at the bottom of graph.
b) Draw a line upward from the flow rate to the
intersection of the curve.
c) Draw a line from the curve intersection to
the right edge of the graph to determine
pressure drop in ft of water [kPa].
8. Determine the friction head for the system.
9. Size the pump or circulator.
10. Determine the piping arrangement (one-pipe, two-
pipe, direct return, or two-pipe reverse return).
11. Determine the type of air removal vent to be used.
12. Determine if a pressure relief valve should be used.

VALVE SELECTION

Use Table 8 to choose the correct valve for the applica-
tion based on the Cv rating determined during system
sizing.
140 150 160 170 180 190 200
[60]
[66] [71] [77] [82] [88] [93]
FLUID TEMPERATURE
54
MAXIMUM FLUID
TEMPERATURE
LINE
210 220 230 240 250
[99] [104] [110] [116] [121]
M8164