Triad Triumph series, Руководство пользователя

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Figure 8.3: Piping Method #1 - Heat + Indirect Water Heater
Feet Straight Pipe. From Table 8.7, we see that a Taco 008 will pump at 8 GPM through a T300 with 56 equivalent
feet and an indirect water heater. The Taco 008 is just large enough to work in this application (a Taco 009 could
also be used if desired).
1” piping is used in the indirect water heater branch from the 1-1/2 x 1-1/2 x 1 Tees in the secondary loop all the way to
the coil connections on the indirect water heater.
4) Multiple Indirect Water Heaters - Pipe multiple indirect water heaters as shown in Figure 8.8. The use of reverse-
return manifold ensures that the boiler water flow will be evenly divided between the two indirects. Table 8.7 shows
pump/piping sizing guidelines for up to two of Triad’s indirect water heaters. Measure the length of the I.W.H. loop to
the furthest indirect water heater. When figuring the equivalent length, do not count the two Tees in the indirect water
heater manifold.
5) Indirect Water Heater By-pass - Some of the piping options shown in Table 8.7 require the use of a bypass around the
indirect water heater. This is done when the required boiler water flow through the indirect water heater is far lower than
the absolute minimum required flow through the boiler. The use of a bypass permits the use of a much smaller pump than
would otherwise be required. Refer to Figure 8.3 for the location of this bypass. The bypass pipe size should be the same
as the rest of the I.W.H. loop.
When the boiler is set-up, start with the throttling valve in the bypass fully open. Initiate a domestic hot water draw
and make sure that the boiler is operating at high fire in response to a call for DHW. Then slowly close the bypass valve
until the temperature rise across the boiler is 40°F or less.
6) Maximum Input on Call for DHW - In most of the applications shown in Table 8.7, the boiler output required for the
indirect water heater is significantly less than the maximum boiler output. This means that when the boiler is responding
to a call for DHW, the flow rate through the boiler can be smaller than is required when responding to a call for space
heating. As a result, smaller piping and circulators can often be used for the IWH loop. In order to take advantage of
this, however, it is necessary to limit the boiler’s firing rate when it is responding to a call for DHW. Table 8.9 shows the
maximum firing rate that is permissible at various boiler water flow rates. The input of this boiler is determined by the
fan speed. The maximum fan speed allowed when responding to a call for DHW is defined by parameters 15 and 16 in
the MCBA (See Appendix A for more information on settings and parameters). Both the firing rate and maximum DHW
fan speed are shown in Table 8.9 for various flow rates. Factory default maximum DHW fan speeds are shown in bold. In
most cases, it should not be necessary to change these parameters in the field.