Condair Nortec RS 10, Engineering Manual

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44
Planning
2596995_0_EN_1905 Nortec RS
High Limit Switch
A high limit switch connected to the humidifier's security loop is used to limit the humidity in the supply
air from reaching saturation conditions, which can lead to water damage. Typically an On/Off duct hu-
midistat will suffice for this application, but there are several applications where modulating transducers
or humidistats should be used, including the following:
• When using a variable air volume (VAV) air handling system.
• When a high limit switch must be installed after a bend or obstruction in the supply duct.
• Applications that require very high air exchange rate, or 100% outdoor air.
• Installations with short steam absorption distances.
The following installation requirement must be observed when using a high limit switch in a duct distri-
bution system:
The distance between the steam distributor and the Condair duct humidistat or transducer should be
minimum 10 ft (3 m), or greater than the calculated absorption distance. Refer to
Figure 24 on page 43
.
Humidity Controller
The humidity controller detects the relative humidity in the conditioned environment and provide feed-
back to the humidifier. The Nortec RS humidifier is compatible with On/Off humidistats, and transducers
(RH sensor), but there are several applications where modulating transducers or humidistats should be
used, including the following:
• When using an economizer, or variable air volume (VAV) air handling system.
• Applications that require very high air exchange rate, or 100% outdoor air.
• Applications that require narrow humidity tolerances.
The following installation requirements must be observed when using humidity controllers in a duct
distribution system:
Must be installed in a location representative of the conditioned environment. Controls installed in
exhaust or return ducts are preferred.
Wall-mounted controls can also be installed in the conditioned environment. However, they should
be located in an area that is not exposed to infiltrating air, and where there are no discharge diffusers
or localized variations in temperatures.
Outdoor Temperature Setback
An outdoor temperature sensor should be used to prevent condensation on windows or other surfaces
that are exposed to outdoor air. Condair outdoor temperature sensors are used in conjunction with
Condair humidistats that limit setpoints based upon outdoor temperature – refer to
Table 3 on page 5
for part numbers.
The default setback for the Condair outdoor temperature sensor is shown in
Figure 25 on page 45 , which
can be reconfigured depending on the insulation quality of windows.
The following installation requirement must be observed when outdoor temperature sensor in a duct
distribution system:
The outdoor sensor must be installed in an area that is representative of the outdoor air tempera-
tures – such as a fresh air intake duct, or located directly outside.