Onix Tubing Installation Manual

page 72 Watts Radiant: Onix Installation Manual
For more detailed information, please
read these other publications. This
manual is designed to give a basic
understanding of primary/secondary
piping and to offer several piping
schematics as well as some correspon-
ding electrical diagrams. Watts
Radiant is not responsible for the per-
formance or functionality of these
illustrative diagrams to any particular
project. Please consult a professional
mechanical contractor or a Watts
Radiant representative for detailed
advice.
Mixing Options
Controlling the supply fluid tempera-
ture to the zones is one of the more
critical features of the mechanical sys-
tem design. There are several ways to
achieve this goal, including 3-way mix
valves, 4-way mix valves, injection
pumps, and even standard ball valves.
The most common means is to use
either a three way mix valve or an
injection pump.
Mix Valves
Non-electrical mix valves are designed
to provided a fixed supply temperature
whenever there is a call for heat.
This reduced temperature is achieved
by allowing a controlled amount of
high temperature boiler water to mix
with the cooler return water from the
zone. It is important to choose a mix
valve that has enough flow volume for
the zone design.
Mix valves are sized based on a Cv
value. This value corresponds to the
pressure drop generated by a certain
amount of flow. If a valve is rated with
a Cv of 5, then the valve can move 5
gpm of fluid at 1 psi drop (2.31 ft.-hd.)
through the valve.
If only one zone is being pumped
through a mix valve, make sure the
zone flow requirement is below the Cv
value of the pump. If multiple zones
(pumps) are to be supplied by one
valve, then make sure the combined
flow of the zones does not exceed the
Cv value of the valve. See following
pages for sample piping schematics.
To determine the pressure drop
through the mix valve at a given flow
rate, use the following equation:
where SG is the specific gravity of the
fluid (for water this is 1, for glycol this
is 1.15), and P is the pressure drop
through the valve.
The total pressure drop for the zone is
the combination of the pressure drop
found through the zone, supply/return
piping and the mix valve.
Most manufacturers will provide this
information in a graph similar to what
is seen for pump sizing. Consult the
corresponding mix valve manufacturer
for more sizing information.
Water
System Expansion
Temperature (¡F) Factor
105 0.004
110 0.005
115 0.007
120 0.008
125 0.010
130 0.012
135 0.013
140 0.015
145 0.017
150 0.018
155 0.020
160 0.022
165 0.023
170 0.025
175 0.026
180 0.028
185 0.030
190 0.032
195 0.033
200 0.035
205 0.037
210 0.039
Expansion Factors.
Glycol
System Expansion
Temperature (¡F) Factor
105 0.0048
110 0.006
115 0.0084
120 0.0096
125 0.012
130 0.0144
135 0.0156
140 0.018
145 0.0204
150 0.0216
155 0.024
160 0.0264
165 0.0276
170 0.030
175 0.0312
180 0.0336
185 0.036
190 0.0384
195 0.0396
200 0.042
205 0.0444
210 0.0468
System volume chart.
Tubing I.D. Onix-PEX Fluid Capacity Type M Copper Fluid Capacity
3/8" 6.25 gal./1000 ft. 8.31 gal./1000 ft.
1/2" 10.25 gal./1000 ft. 13.2 gal./1000 ft.
5/8" 16.0 gal./1000 ft. 18.1 gal./1000 ft.
3/4" 25.0 gal./1000 ft. 27.0 gal./1000 ft.
1" N/A 45.5 gal./1000 ft.
1-1/4" N/A 68.2 gal./1000 ft.
1-1/2" N/A 95.4 gal./1000 ft.
Mix Valve
Temperature Gauge
Appendix