Selecting An Rh Setpoint - Nortec NHTC Installation And Operation Manual

Steam Line
The steam line between the cylinder steam outlet and the distributor may be NORTEC steam
hose, copper pipe, or stainless steel pipe or tube. The NHTC/PC is an atmospheric steam
generator so it is very important no restrictions are present in the steam line and that the steam
line is sized properly to carry the full output capacity of the humidifier. It is also important to
minimize the length of steam lines. See Steam Lines and Condensate Returns on page 14 for
information on selecting steam lines and maximum recommended lengths.
Whenever steam is distributed condensate is formed in the distribution system and steam
distributor, manifold, or blower pack. Insulating steam lines is one important way to reduce the
amount of condensate formed. Steam lines must be sloped so that condensate does not collect
in the lines and create a restriction to steam flow.
Condensate Return
The condensate must be collected and removed from the system so that it does not build up
and leak into the duct (or room if blower pack is used). Condensate can be returned to the
NHTC/PC fill cup to reduce water waste or can be fed to drain.

Selecting an RH Setpoint

The optimum humidity setpoint depends on the reasons that a space is being humidified. The
"ASHRAE Handbook – HVAC Applications" recommends specific design relative humidities for
specific applications. See also NORTEC publication "When You Need Humidity" (Form 124A)
for more information on humidity settings.
Health and Comfort - The benefit of humidity is most pronounced for health and comfort in the
40-60% range. A humidity setting of 40-50 % is recommended for this purpose to prevent over
humidifying.
Note: The job site design may have specified a setpoint chosen specifically for the
site. Refer to site documentation and where possible use setpoints specifically
determined for the site.
Temperature Setback - In cold climates it is often necessary to reduce the humidity level in a
space to prevent build up of condensation on the inside of exterior walls, windows, and trim. It
is highly recommended that the temperature setback function of the NORTEC digital controls be
used under these conditions to prevent damage from condensation. The digital control with an
outdoor temperature sensor installed will automatically setback the humidity setpoint to
correspond with outdoor temperature.
Duct High Limit – The duct high limit is intended to prevent saturation and wetting in duct work
at high load conditions. NORTEC recommends a setting of 85% for the duct high limit. It may
be necessary to reduce this setting If the duct work is very cold or in contact with exterior cold
surfaces.
45 | Operation