Taco i Series, Instruction Sheet

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When using an iSeries Mixing Valve, the following piping require-
ments must be considered for proper operation.
1) In order to hydraulically isolate the boiler loop from the injection
or system loop primary/secondary piping must be used. There
must be no more than 4 pipe diameters between the tees in the
boiler loop (Note 1).
2) There must be at least 6 pipe diameters of straight pipe on either
side of the tees (Note 2) in order to prevent the momentum of water
in the boiler loop from pushing flow through the injection loop.
3) There should be a minimum of 1 foot drop on the return pipe
of the injection loop, in order to create a thermal trap (Note 3) and
prevent unwanted heat transfer.
4) When using a 2-way iSeries Mixing Valve, a balancing valve
must be located between the tees in the system loop, in order to
provide a pressure drop to induce flow through the mixing loop.
2-Way iSeries Mixing Valve Selection
In order to properly size the 2-Way iSeries Mixing Valve, follow the design procedure below:
1) Determine the design radiant heating load.
2) Determine the design boiler supply temperature.
3) Determine the radiant system return temperature which is based on the design temperature drop across the radiant system.
4) Determine the design injection flow rate using the following equation:
Eq.1:
5) From the 2-Way Cv chart below, select the valve size with the closest Cv value to the injection flow rate calculated in step 4. Do not
size the 2-Way iSeries Mixing Valve based soley on pipe size.
3-Way iSeries Mixing Valve Selection
Select the 3-Way iSeries Mixing Valve based on the 3-way Pressure Drop chart below.
Sequence of Operation
Power Up and Heat Request
Whenever the iSeries-R is powered up, the LED turns on and the control starts operation. The power to the iSeries-R may be switched
through an end switch (e.g. Taco ZVC/SR style zone control) or a thermostat for intermittent operation, or the power source may be
connected directly to the iSeries-R for continuous operation.
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Design Injection Flow Rate (US GPM) =
Design Radiant Heating Load (Btu/hr)
500 x (Boiler Supply - Radiant System Return)
1/2"
(Cv = 1.5)
PSI GPM
Flow
Ft Head
0.11
0.44
1.03 0.09 0.21 0.11 0.26
1.00 2.31 0.21 0.48 0.25 0.58
1.78 4.11 0.37 0.85 0.44 1.03
1.47 3.39 1.78 4.11
3.31 7.64 4.00 9.24
5.88 13.58
1/2
1
2
4
6
8
1 1/2
0.26
3/4"
(Cv = 3.3)
PSI
i Series: 3-Way Valve Pressure Drop
Ft Head
0.02 0.05
1"
(Cv = 3.0)
PSI Ft Head
0.03 0.06
1/2" 4.9
10.3
8.9
3/4"
1"
i Series: 2-Way Cv
Size Cv