Nortec NHTC 10-10, A.General, This Function B.On/Off Controls, C.Modulating Controls, Page 53

7.CONTROLS

A.GENERAL

(1)NORTEC humidifiers all accept on/off controls for their security loop. Many NORTEC humidifiers can also accept modulating or transducer signals for control (See the features section for each specific model).

CAUTION

REGARDLESS OF SELECTING ON/OFF OR MODULATING CONTROL

METHOD, NORTEC HUMIDIFIERS MUST HAVE CLOSED CIRCUIT

ACROSS ITS ON/OFF SECURITY LOOP CONTROL TERMINAL TO

OPERATE. NORTEC HIGHLY RECOMMENDS THE USE OF A HIGH

LIMIT HUMIDISTAT AND AN AIR PROVING SWITCH IN SERIES FOR

THIS FUNCTION.

B.ON/OFF CONTROLS

(1)On/Off controls are used in all NORTEC humidifier security loops. The digital humidistat can also be used as a space humidity controller. These controls include:

(a)Air Proving Switch – duct mounted, pressure differential switch, adjustable set point from 0.07 IWC to 12.0 IWC, good for positive, negative or differential pressure applications, stops humidifier if duct air pressure is not sensed. Turns humidifier off if air handler fails.

(b)Duct Mounted Digital Humidistat – control or high limit, adjustable set point from 15-90% rh with accuracy fixed at ±3% at 25°C, operating range of 0-95% rh, closes on humidity drop for control and opens on rise for high limit duct application.

(c)Wall Mounted Digital Humidistat – control or high limit, adjustable set point from 15-90% rh with accuracy fixed at ±3% at 25°C, operating range of 0-95% rh, closes on humidity drop for control and opens on rise for high limit application.

(d)On/Off Controls Supplied by Others – Can be used as long as they have a dry set of contacts capable of passing a 24-VAC, 2-A maximum signal.

C.MODULATING CONTROLS

(1)Modulating Controls are used to send a modulating demand signal to the NORTEC humidifier. Different models can accept different signals (see features section for each specific model) NORTEC supplied controllers send a 0-10 VDC demand signal. This signal can be used as a control and in some models can also be used as a modulating high limit. These controls include:

(a)Wall Mounted Digital Humidistat with Integrated Sensor – control or high limit, adjustable set point from 15-90% rh with accuracy fixed at ±3% at 25°C, outputs a 0-10 VDC signal.

(b)Wall Mounted Digital Humidistat Without Sensor – control or high limit, adjustable set point from 15-90% rh with accuracy fixed at ±3% at 25°C, outputs a 0-10 VDC signal. Requires a remote transducer sensor supplying a 2-10 VDC signal.

(c)Duct Mounted Digital Humidistat With Sensor – This package comes with both a remote sensor and a wall mounted controller without sensor. Control or high limit, adjustable set point from 15-90% rh with accuracy fixed at ±3% at 25°C, outputs a 0-10 VDC signal.

10-10

Page 53 2008-10-01