Nortec On Digital Wall Humidistat User Manual

1 - Wall Humidity Control Installation

Location:

1 Do not install humidistat on an outside wall, near a heat source and/or in direct sunlight.
2 Install the humidistat on a surface that is flat and clean.
3 Install a vapor barrier to prevent sensor from interacting with inner wall draft.
4 Use a sealed, single gang electrical mounting box (recessed in the wall) to mount the humidity sensor.

Installation:

1 Pull cables 6” (15 cm) out of the wall.
2 Remove front face with digital display by loosening plastic retaining screw at the bottom. The front face

will unhinge from the top of the retaining clips.

3 Connect the control wires to the terminals according to wiring diagram 2548733 in this document. Figure

2 outlines the terminal layout.

4 Secure the metal bracket to the mounting electrical box using 2 screws (#6 x 3/4” Phillips). Make sure the

heads do not stand out more than 1/5” (5 mm) from mounting surface.

5 Remount front face on metal bracket. Ensure clips engage the grooves on top of the bracket. Gently

tighten bottom plastic retaining screw.

Configuration:

1 Using keypad, set specified humidity. For general health and comfort, a humidity setting of 50% is

recommended.

2 See Table 3 for outdoor temperature setback configuration, if optional outdoor temperature sensor is

supplied (P/N 2520263 or 2553858).

On/Off Digital Wall Humidistat Installation Instructions

1234

567

8

Humidify Relay
24 Vac
Com

Fan (Furnace) Relay

NTC Sensor

Figure 2: Terminal Strip

112 (4.4")

73 (2.9")

32 (1.2")

58 (2.3")

15

(.6")

Figure 1: Wall Humidistat Installation Locations

Figure 3: Dimensions

This document covers the operation and installation instructions for the following digital humidistat:
Part #: 2548731
Description: ON/OFF Wall Humidistat

2549736-D | 22 July 2014 Introduction | 1

1
2

3

4
5

6

7

Legend:

1 Display of current humidity value.
2 Display of setpoint.
3 Snowflake displayed if outdoor temperature setback active.
4 Adjusts setpoint and calibration (up).
5 Power ON/OFF.
6 Toggles between RH setpoint and temperature (if temperature sensor

present).

7 Adjusts setpoint and calibration (down).

Parameter

Description

Range

Default

UP 00

Enable change of operation modes

ON, OFF

ON (Enabled)

UP 01

Enable change of setpoints

ON, OFF

ON (Enabled)

UP 02

State after power failure:
0 = Switched OFF, 1 = Switched ON, 2 = state before power failure

0, 1, 2

2

UP 03

Celsius or Fahrenheit, Select ON for Fahrenheit, OFF for Celsius

ON, OFF

OFF (Celsius)

UP 04

Select contents of small digits in standard mode:
00 = OFF
01 = Setpoint
02 = Humidity Sensor
03 = External Temperature Sensor

0…3

01 Standard:

show setpoint

Parameter

Description

Range

Default

CP 00

Minimum setpoint limit in humidification mode

0…100%

10%

CP 01

Maximum setpoint limit in humidification mode

0…100%

90%

CP 02

Start delay for fan
(Time the fan runs before control output starts)

0…255 s

10 s

CP 03

Stop delay for fan
(Time the fan keeps running after control output stops)

0…255 s

90 s

Parameter

Description

Range

Default

CP 04

Enable temperature setback
OFF = Temperature setback is disabled
ON = Temperature setback is enabled

ON, OFF

OFF

CP 05

Setpoint limit at full setback

0…100%

20%

CP 06

Lower temperature limit:
Outside temperature with maximum setback
The setpoint will be equal to the minimum setpoint limit

-40…60°C

-40…160°F

-30°C (-22°F)
CP 07

Upper temperature limit:
Outside temperature at begin of setback.

-40…60°C
40…160°F

0°C (32°F)

CP 08

Number of seconds taken into account to calculate the averaging input signal.
Low value = fast response

High value = slow response

0…100

30

Duct Humidistat LCD Display

Sensor Calibration

The humidity sensor is factory calibrated, however, it can be field recalibrated. The calibration routine can be accessed by pressing the option key for > 3
seconds. Option key = the right key on the wall mount and middle key on the right side of the duct mount. Once the display changes select CAL H, press OPTION
key again - the offset value is now shown.
Press up down keys to change. Press option key again to save changed value and return to previous level.

Login Procedure

Most applications can use default values.
User Parameters (Password 0009)

1 Press UP and DOWN button simultaneously for three seconds. The display shows the software version in the large digits and the product code in the small

digits.

2 Pressing the OPTION button will indicate CODE on the small digits and 0000 on the large digits.
3 The code for accessing the control parameters is 0009
4 Select this using UP or DOWN buttons.
5 Press OPTION button after selecting the correct code.
6 Once logged in, the parameter is displayed immediately.
7 Select the parameters with the UP/DOWN buttons. Change a parameter by pressing the OPTION button. Three triangles will show up on the lower right and

indicate that the parameter may be modified now. Use UP or DOWN buttons to adjust the value.

8 After you are done, press OPTION or POWER in order to return to the parameter selection level.

Table 1: User Parameters

Control Parameters (Password 0241)
NOTE: Only experts should change these settings! See user parameters for login procedure.

Table 2: Output Configuration

Table 3: Temperature Setback Configuration - *For humidity control only.

2 | Introduction