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RT-SVX073A-EN
illustrated in Figure 31, p. 49.
Use the following guidelines to enhance both the
installation and operation of the “wet heat” system.
Figure 32, p. 49 illustrates the recommended piping
configuration for the hot water coil. Table 18, p. 49 lists the
coil connection sizes.
Note: The valve actuators are not waterproof. Failure to
protect the valve from moisture may result in the
loss of heating control.
1. Support all field-installed piping independently from the
heating coil.
2. Use swing joints or flexible connectors adjacent to the
heating coil. (These devices will absorb the strains of
expansion and contraction).
3. All return lines and fittings must be equal to the
diameter of the “outlet” connection on the hot water coil.
4. Install a “Gate” type valve in the supply branch line as
close as possible to the hot water main and upstream
of any other device or takeoff.
5. Install a “Gate” type valve in the return branch line as
close as possible to the return main and down stream
of any other device.
6. Install a strainer in the hot water supply branch as
shown in Figure 32, p. 49.
7. Install the 3-way valve in an upright position, piped for
valve seating against the flow. Ensure that the valve
location lends itself to serviceability.
8. The Type “W” hot water coil is self-venting only when
the tube water velocity exceeds 1.5 feet per second
(fps). If the tube velocity is less than 1.5 feet per
second, either:
a. install an automatic air vent at the top of the return
header, using the tapped pipe connection
or,
b. vent the coil from the top of the return header down
to the return piping. At the vent connection, size the
return piping to provide sufficient water velocity.
9. Install a “Globe” type valve in the Bypass line as shown
in Figure 32, p. 49.
Steam Heat Units
Steam heating coils are factory installed inside the heater
section of the unit. The coils are pitched within the units to
provide the proper condensate flow from the coil. To
maintain the designed degree of pitch for the coil, the unit
must be level.
Once the unit is set into place, the steam piping and the
factory provided 2–way modulating valve must be installed.
The valve can be installed inside the heater section or near
the unit. If the valve is installed in a remote location, use
field supplied wiring to extend the control wires from the
heater section to the valve. Two access holes are provided
in the unit base as illustrated in Figure 31, p. 49.
Use the following guidelines to enhance both the
installation and operation of the “wet heat” system. Figure
33, p. 50 illustrates the recommended piping
configurations for the steam coil.Table 18, p. 49 lists the
coil connection sizes.
Note: The valve actuators are not waterproof. Failure to
protect the valve from moisture may result in the
loss of heating control.
1. Support all field-installed piping independently from the
heating coil.
2. Use swing joints or flexible connectors adjacent to the
heating coil. (These devices will absorb the strains of
expansion and contraction.)
3. Install the 2-way valve in an upright position. Ensure
that the valve's location lends itself to serviceability.
4. Pitch the supply and return steam piping downward 1"
per 10' of run in the direction of flow.
5. All return lines and fittings must be equal to the
diameter of the “outlet” connection on the steam coil(s).
If the steam trap connection is smaller that the coil
“outlet” diameter, reduce the pipe size between the
strainer and the steam trap connections only.
6. Install a 1/2" 15 degree swing-check vacuum breaker at
the top of the return coil header using the tapped pipe
connection. Position the vacuum breaker as close to
the coil as possible.
Note: Vacuum breakers should have extended lines
from the vent ports to the atmosphere or connect
each vent line to the return pipe on the discharge
side of the steam traps.
7. Install a “Gate” type valve in the supply branch line as
close as possible to the steam main and upstream of
any other device.
8. Install a “Gate” type valve in the return branch line as
close as possible to the condensate return main and
downstream of any other device.
9. Install a strainer as close as possible to the inlet of the
control valve and steam trap(s). Steam trap selection
should be based on the maximum possible condensate
flow and the recommended load factors.
10. Install a Float-and-Thermostatic (FT) type trap to
maintain proper flow. It provides gravity drains and
continuous discharge operation. FT type traps are
required if the system includes either of the following:
a. an atmospheric pressure/gravity condensate return
or
b. a potentially low pressure steam supply.
11. Position the outlet or discharge port of the steam trap at
least 12" below the outlet connection on the coil(s).
This will provide adequate hydrostatic head pressure to
overcome the trap losses and assure complete
condensate removal.
If two steam coils are stacked together, they must be
piped in a parallel arrangement. The steps listed below
should be used in addition to the previous steps.Figure
Installation
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