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
7.Install the
8.The Type "W" hot water coil used in SLHF 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;
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
Table
Connection Sizes for Hot Water & Steam Coil (See Note 1)
| Heat | Coil Connections | |
| Section | (diameter in inches) | |
Unit Model | Capacity |
|
|
and Size | (Note 2) | Supply | Return |
High or | |||
to 130 | Low Heat |
|
|
High or |
|
| |
to 30 | Low Heat | 3" | |
High Heat | 3" | ||
to 75 |
|
|
|
(Note 3) | Low Heat | 1" | |
| Low Heat |
|
|
to 130 | (Note 3) |
|
|
Notes:
1.Type W
2.See Digit 9 of the unit model number to determine the heating capacity.
3.SSH_ - 40 to 130 Ton units have multiple headers.
Steam Heat Units (SSH_)
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 main- tain 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 two way modulating valve must be in- stalled. The valve can be installed inside the heater section or near the unit. If the valve is installed in a remote location,
Installation (Continued)
use field supplied wiring to extend the control wires from the heater section to the valve. Two access holes are pro- vided in the unit base as illustrated in Figure
Following the guidelines listed below will enhance both the installation and operation of the "wet heat" system.
Figure 3-13 illustrates the recommended piping configura- tions for the steam coil. Table 3-5 list 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 ex- pansion 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" di- ameter, 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).
10.Steam trap selection should be based on the maximum possible condensate flow and the recommended load factors.
11.Install a Float-and-Thermostatic (FT) type trap to main- tain proper flow. They provide gravity drains and continu- ous discharge operation. FT type traps are required if the system includes either;
a.an atmospheric pressure/gravity condensate return; or,
b.a potentially low pressure steam supply.
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