Triad Triumph series, Руководство пользователя

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Method 1: Primary/Secondary Piping
This method can be used in heat-only applications as shown in Figure 8.2 or with an indirect water heater as
shown in Figure 8.3. This method relies on primary/secondary pumping to ensure that the required flow is
always maintained through the boiler. In this system, the flow rate through the boiler is completely independent of
the flow rate through the heating system. Use the following guidelines to ensure that the boiler will have the required
flow shown in Table 8.1 regardless of the flow in the heating system.
1) Primary Loop Piping - Size the primary circulator and piping to obtain the design flow rate through the heating
system as you would on any other heating system. All piping between the expansion tank and secondary
connection tees must be at least as large as that shown in Table 8.5, column (a). In order to keep the flow rates in
the primary and secondary loops independent of each other, provide at least 8 diameters of straight pipe upstream
of the first secondary tee and 4 diameters downstream of the second secondary tee. Keep the distance between the
expansion tank and the first secondary tee as short as practical.
2) Secondary Loop (“Boiler Loop”) Piping – The secondary (or “boiler loop”) piping is shown shaded in figure 8.4a.
All piping in this loop must be the size shown for the boiler in Table 8.5, column (a). To size the circulator for this
loop:
a) Select one of the boiler water flow rates shown in Table 8.5, column (b) for the boiler and pipe size being
installed. When selecting the required boiler flow rate, keep in mind that if the flow rate in the primary loop
exceeds the flow rate through the boiler, it will not be possible to obtain a 180°F supply temperature in the
primary loop. This is because the supply water exiting the boiler will be mixed with cooler system return water
before entering the radiation.
b) Count all fittings in the planned secondary loop. In doing so, do not count the secondary connection tees, unions,
or the fittings supplied with the boiler (these have already been accounted for).
c) Using Table 8.6, find the equivalent lengths of all fittings in the secondary loop. Total these equivalent lengths
and add them to the total length of planned straight pipe in the secondary loop. The result is the total equivalent
length of the secondary loop.
d) Refer back to the row in Table 8.5 from which the flow rate and pipe size were selected:
If the maximum equivalent length shown in column (e) is in excess of the total equivalent length •
calculated in Step (c) above, use the pipe size selected, along with the circulator shown in Table 8.5,
column (d).
If the maximum equivalent length shown in column (e) is in less than the total equivalent length calculated •
in Step (c) above, a larger pipe size and/or larger circulator is required. Select another circulator/pipe size
combination from Table 8.5 and repeat steps (b-d) above.
3) Indirect Water Heater Loop Piping (If Indirect Water Heater is Used) – The indirect water heater loop piping is
shown shaded in Figure 8.4b. Some of the piping in this loop is common to the secondary loop sized above. Piping
common to both loops is always sized from Table 8.5, column (a) as described above . All indirect water heater
loop piping that is not common (the “I.W.H branch”) is sized from Table 8.7, column (a). If the indirect water
heater connections are smaller than the pipe size called for in Table 8.7, column (a), reduce the pipe size at the
indirect water heater connections. To size the circulator:
a) Count all fittings in the planned Indirect Water Heater Loop (all shaded piping in Figure 8.4b). In doing so, you
will be counting some piping and fittings which are common to the heating system secondary (“boiler loop”)
piping and which were counted in Step 2a above. Do not count the fittings supplied with the boiler. If Table 8.7
requires a bypass, do not count the pipe and fittings in the by-pass.
b) Using Table 8.6, find the equivalent lengths of all fittings in the indirect water heater loop. If the I.W.H. branch
pipe size is smaller than the secondary loop pipe size, calculate the equivalent lengths for all fittings (including
the larger size fittings common to both loops) based on the smaller size. Total these equivalent lengths and
add them to the total length of planned straight pipe (of both sizes) in the indirect water heater loop. The result
is the total equivalent length of the indirect water heater loop.
c) Refer back to the row in Table 8.7 from which the flow rate and I.W.H. branch pipe size were selected:
• If the maximum equivalent length shown in column (f) is in excess of the total equivalent length
calculated in Step (b) above, use the IWH branch pipe size selected, along with the circulator shown in
Table 8.7, column (e).
• If the maximum equivalent length shown in column (f) is in less than the total equivalent length
calculated in Step (b) above, a larger pipe size and/or larger circulator is required. Select another
circulator/pipe size combination from Table 8.7 and repeat steps (a-b) above.
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