Table 53: Coil component sizing
Model
Coil
Valve size (in.)
Header size (in.)
Connection size
(inlet / outlet)
Hot water (low heat)
2
1.5
1.5 / 1.5
Hot water (high heat)
2
2.5
2.5 / 2.5
Steam (low heat)
2
2
2 / 1.5
25 ton to 30 ton
Steam (high heat)
2
2
2 / 1.5
Hot water (low heat)
2
2
2 / 2
Hot water (high heat)
2
3
3 / 3
Steam (low heat)
2
2
2 / 1.5
40 ton to 50 ton
Steam (high heat)
2
2
2 / 1.5
Steam coil
•
The factory installed steam coil is located in
the discharge air section of the unit.
•
The steam coil is designed for a maximum
working pressure of 15 psig.
•
The unit can be ordered with a two-way
modulating valve shipped loose from the
factory to be installed in the field. See the
submittal package for the valve part number
and specifications.
•
Install the modulating valve and strainer on
the inlet line.
•
Piping to and from the steam coil must be
field supplied and installed. This includes the
strainer, pipes, and pipe fittings. See Figure
•
Piping locations can also be found in the
submittal data.
•
A field provided and installed valve can also
be used as long as the valve matches the
specifications/ratings of the factory installed
valve.
•
Connect the modulating valve to the customer
terminal board using the hot water/steam
heating valve output (HTGV-O) at terminal
Humidifier
The rooftop unit can be ordered with an optional
factory installed steam humidifier manifold. The
steam control valve, Y (wye) type strainer, and
steam trap are factory provided and shipped loose
for field installation. Steam is provided by others.
Piping locations can be found in the submittal data.
HUM-O (humidifier output) and HUM-C (humidifier
command) points are located on the customer
terminal board. See Figure 41.
Return air and discharge air humidity sensors are
provided to maintain zone/return air humidity.
Steam inlet piping and condensate drain connection
sizes vary by tonnage sizes. For more information,
refer to Table 35. The steam control valve is a 24 VAC
normally closed, spring return actuator. All piping
necessary for installing the strainer, valve, and trap
are field provided and installed.
Figure 40: Humidifier connections
Tempmaster
®
Omni™ Premier 25 Ton to 80 Ton Rooftop Units Installation and Maintenance Guide
80
Tempmaster
