Installation
38 RT-SVX35H-EN
Hot Water Heat Units (WLHE)
Hot water heating coils are factory installed inside the
heater section of the unit. Once the unit is set into place,
the hot water piping and the three way modulating valve
(factory provided, field installed) must be installed. The
valve can be installed inside the heat section or near the
unit. If the valve is installed in a remote location, use field
s
upplied wiring to
extend the control wires from the heater
section to the valve. Two access holes are provided in the
unit base as shown in Figure 4, p. 19 - Figure 8, p. 23.
Following the guidelines listed below will enhance both
the installation and operation of the "wet heat" system.
Figure 22, p. 39 illustrates the recommended piping
configurations for the hot water coil. Table 10, p. 38 lists
the coi
l 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
d
iameter 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 lineas
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
sh
own in Figure 22.
7. Install the 3-way valve in an upright position, piped for
valve seating against the flow. Ensure that the valve’s
location lends itself to serviceability.
8. The Type "W" hot water coil used in WLHE units 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;
o
r,
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 22, p. 39.
Steam Heat Units (WSHE)
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.
Important: To maintain the designed degree of pitch for
the coil, the unit must be installed
absolutely level.
Once the unit is set into place, the steam piping and the
two way modulating valve (factory provided, field
installed) must be installed. The valve can be installed
inside the heater section or near the unit. If the valve is
install
ed 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
shown in Figure 4, p. 19 - Figure 8, p. 23.
Following the guidelines listed below will enhance both
the installation and operation of the "wet heat" system.
Figure 24, p. 40 illustrates the recommended piping
configurations for the steam c
oil. Table 10, p. 38 list the
coil connection sizes.
Figure 21. Flu assembly
Table 10. Connection sizes for hot water & steam coil
(a)
(a) Type W coils—with center offset headers—are used in WLHE units; Type
NS coils are used in WSHE units.
Unit Model and
Size
Heat Section
Capacity
(b)
(b) See Digit 9 of the “Model Number Descriptions,” p. 5 to determine the
heating capacity.
Coil Connections
(diameter in inches)
Supply Return
WLHE (20 - 130)
Casing 2 - 9
High or Low Heat 2-1/2” 2-1/2”
WSHE (20 - 30)
Casings 2 & 3
High or Low Heat 3” 1-1/4”
WSHE (90-130)
Casing 9
Low Heat(c) 1-1/2” 1”
WSHE (40 - 75)
Casings 4, 5 & 6
(c)
(c) WSHE - 40 thru 130 Ton units have multiple headers
High Heat 3” 1-1/2”
Low Heat 1-1/2” 1”
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