MS Electronics E914 Product Manual

Product Guide

E914

today, tomorrow and in the future

mselectronics.co.uk

Robust Humidistat
with semi-automatic on/off control

energy saving controls

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Issue 2.0

Product Overview

The E914 offers a calibration-free, high quality solution to tamperproof humidity control. It utilises
a high-accuracy humidity sensor in conjunction with its robust die-cast aluminium case and
tamperproof screws to ensure vandal-resistant yet accurate tamperproof energy control.

The E914 regulates to a fully adjustable relative humidity set-point between 5% RH and 95% RH,
combined with an adjustable relative humidity hysteresis (differential) of anything between 1% RH
and 10% RH.

The E914’s integrated pushbutton allows the room user to switch off the unit. Humidity control will
automatically be restored after the “Off Timeout” period has elapsed. LED indicators illuminate to
display the state of the humidistat (Green = ON (humidity control enabled) or Red = OFF (humidity
control disabled)).

Product Wiring

1. IMPORTANT: ensure all electrical connections are isolated before commencing any work on the

unit.

2. Power to the humidistat is provided via the Live and Neutral input terminals labelled “L” and “N”
(230V AC, 50Hz). This supply should be suitably fused.

3. NOTE: This humidistat MUST be earthed using the earth terminal provided.

4. A voltage-free changeover relay output capable of switching loads of up to 16A, 250V AC
(resistive) is provided by the humidistat. Connect to your application in an appropriate manner
given the following:

• If the sensed humidity is higher than the setpoint humidity:
The Common “COM” terminal is connected to the Normally Open “N/O” terminal.
(The Normally Closed “N/C” terminal is disconnected).

• If the sensed humidity is lower than the setpoint humidity, or the OFF mode is selected:
The Common “COM” terminal is connected to the Normally Closed “N/C” terminal.
(The Normally Open “N/O” terminal is disconnected).

Figure 1 Typical wiring example

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Issue 2.0

Installation

1. IMPORTANT: ensure all electrical connections are isolated before commencing any work on the

unit.

2. Unscrew the 4 security screws using MS Electronics tamperproof screwdriver MSD-152 to
remove the front cover.

3. Mount the unit securely using any suitable xing in conjunction with the mounting holes
provided in the unit.

4. Connect the wiring as shown in the diagram (or any suitably appropriate form) using the
convenient pluggable terminal blocks provided. Make sure to choose the correct output
terminals that are suitable to your application (their operation is described in the ‘Product Wiring’
section).

5. On the remote sensor version, 2-core screened cable should be used to connect the remote
sensor to the thermostat. The screen should be connected to the earth terminal ONLY (do not
connect the screen to anything at the remote sensor end).

6. Adjust the internal controls to suit the installation operational requirements (see below).

7. Replace the cover securely using the 4 security screws.

Operation

1. IMPORTANT: ensure all electrical connections are isolated before commencing any work on the

unit.

2. Adjust the “Setpoint” dial to the relative humidity level the room is to be regulated to.

3. Set the “Differential” to the total relative humidity swing either side of the “Setpoint” that the
room humidity is required to keep within.

4. Set the “Off Timeout” dial to the number of hours that humidity control can be disabled for
before it is automatically re-enabled.

5. Example of a typical set-up:

Setpoint set to 55% RH
Differential set to 4% RH
Off Timeout” set to 10 hours
In the ON mode the unit will maintain the humidity between 53% RH and 57% RH.
The unit will permanently maintain this control unless it is switched OFF via the pushbutton.
After 10 hours in the OFF mode the E914 will automatically revert back to the ON mode.

Technical Specication

Power supply: 220V - 240V AC 50Hz (live/neutral/earth)
Output switch rating: 16A, 250V AC 50Hz (resistive)
Output switch type: Changeover relay (volt-free)
Humidity control: 5% RH to 95% RH
Humidity differential: 1% RH to 10% RH
Sensor accuracy: +/- 3% RH

Sensor drift:

+/- 1.2% RH over 5 years (no calibration

required)
Guarantee: 5 Years
Weight: 0.33Kg
Dimensions: 120mm x 95mm x 35mm

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MS Electronics reserves the right to alter or change this specification without prior notice.

IMPORTANT INSTALLATION NOTICE

The installation of this product should be carried out in accordance with the latest IEE wiring

regulations and all wiring completed by a qualified electrician.

Technical Support

For further help or information on this and the other products in the MS Electronics range

visit www.mselectronics.co.uk or call 0333 666 1176.

Alternatively, email [e-mail]

Additional copies of this product guide can be downloaded from our website.

Product Warranty

MS Electronics guarantees all their products against manufacturing defects for

5 years from the purchase date. If your product is found to be faulty, MS Electronics will,

at their discretion, repair or replace the product free of charge.

Note

Any modification or damage to the outer casing of the product, as well as any

damage to the product due to abuse or incorrect wiring may invalidate the guarantee.

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