Honeywell ST9400A

ST9400A – User Guide
1 Day Programmer, 2 channel
Honeywell Control Systems Ltd.
Arlington Business Park,
Bracknell
Berkshire
RG12 1EB
Technical Help Desk: 08457 678999
www.honeywelluk.com
50022737-004 A
© 2007 Honeywell International Inc.
Features
Easy to use slider and buttons combined with ‘LoT’™ Technology and an
‘OK’ button, allows you to confi rm changes and stay in control.
LoT™ Technology provides you with informative ‘on-screen’ feedback and operational
assistance as and when required.
Extra Large LCD (Liquid Crystal Display) with Backlight provides added user
friendliness and clearer viewing – even in the dark.
Independent 1-day Heating & Hot Water Programmes let you choose settings
built into ST9400A for each day of the week to match your lifestyle, while maximising
energy savings, or alter them to your personal settings.
Automatic Summer/Winter Time Change will adjust the clock forward and backward
automatically when the clocks change, saving you having to change your ST9400A
every time.
Built-in Memory holds your programme indefi nitely - even if the mains power fails.
Energy Effi ciency and the Environment
Home energy use is responsible for more than ¼ of the total UK carbon emissions
which contribute to climate change. Heating and hot water systems based on
boilers account for of this fi gure, so it is important to understand how your
controls can help to maximize energy effi ciency while maintaining your comfort.
Your Programmer should be used in conjunction with appropriate temperature
controls. In order to save energy the following general points should be
observed:
1. Ensure your system contains a room thermostat and a hot water thermostat,
and that both are set to appropriate temperature levels: typically 20°C for the
room temperature and between 55 - 60°C for the hot water temperature.
2. Programme your heating and hot water to be off when you are not in the house.
If you are concerned about possible frost damage to any exposed pipe work, it
is advisable to fi t a frost protection system – your installer can advise you about
this.
3. Think about how you use your domestic hot water – if you have a storage
system, it is not necessary to have this switched on all the time, even when you
are in the house.
4. Consider the heat up times required for your central heating. Every home
responds differently when the heating is switched on. Adjust the start time so
that you are not cold when you get up in the morning. A shorter heat up time is
required for other heating periods.
5. In the evening, when the house is up to temperature, it is often possible to
switch off the heating up to an hour before you go to bed, without any noticeable
reduction in comfort.
PLEASE RESPECT YOUR ENVIRONMENT!
Take care to dispose of this product and any packaging or literature in an appropriate way
This product and its associated documentation and packaging are protected by various intellectual
property rights belonging to Honeywell Inc. and its subsidiaries and existing under the laws of the UK
and other countries. These intellectual and property rights may include patent applications, registered
designs, unregistered designs, registered trade marks, unregistered trade marks and copyrights.
Honeywell reserves the right to modify this document, product and functionality without notice. This
document replaces any previously issued instructions and is only applicable to the product(s)
described.
This product has been designed for applications as described within this document. For use outside of
the scope as described herein, refer to Honeywell for guidance. Honeywell cannot be held responsible
for misapplication of the product(s) described within this document.
Manufactured for and on behalf of the Environment and Combustion Controls Division of Honeywell
Technologies Sarl, Ecublens, Route du Bois 37, Switzerland by its Authorised Representative Honeywell Inc.
This document is to be left with the user
and forms part of a Home Information Pack
WHAT IS A PROGRAMMER?
...an Explanation for Householders (as recommended by the Energy Savings Trust)
Programmers allow you to set ‘On’ and ‘Off’ time periods. Some models switch the central heating
and domestic hot water on and off at the same time, while others allow the domestic hot water
and heating to come on and go off at different times. Set the ‘On’ and ‘Off’ time periods to suit
your own lifestyle. On some programmers you must also set whether you want the heating and hot
water to run continuously, run under the chosen ‘On’ and ‘Off’ heating periods, or be permanently
off. The time on the programmer must be correct. Some types have to be adjusted in spring and
autumn at the changes between Greenwich Mean Time and British
Summer Time. You may be able to temporarily adjust the heating
programme, for example, ‘Override’, ‘Advance’, or ‘Boost’. These
are explained in the manufacturer’s instructions. The heating will
not work if the room thermostat has switched the heating off. And,
if you have a hot-water cylinder, the water heating will not work if
the cylinder thermostat detects that the hot water has reached the
correct temperature.

Honeywell ST9400A Specifications

General

Model	ST9400A
Category	Thermostat
Voltage	230V AC
Switching Current	3A
Mounting	Wall-mounted
Display	LCD
Battery Backup	No
Contact Voltage	230V AC
Frequency	50Hz
Type	Programmer
Switch Rating	3A
Temperature Range	5°C to 30°C
Contact Rating	3A

Summary

What Is a Programmer?

General Description

Describes the ST9400A programmer's function and its interaction with other temperature controls in the home.

Programmer Usage Principles

Explains how to use the programmer based on lifestyle and features like override, extra hour, and mode buttons.

Features Overview

User Interface and Display

Highlights LOT™ Technology, extra large LCD with backlight for user friendliness and clear viewing.

Programming and Time Management

Covers independent 1-day heating/hot water programs and automatic summer/winter time changes.

Energy Saving Features

Mentions built-in memory that holds programs indefinitely and general energy efficiency tips.

Energy Efficiency and the Environment

ST9400 A Controls Layout

Device Controls and Indicators

Identifies physical controls like buttons, sliders, indicator lamps, and display elements.

Getting Started With Your ST9400 A

Setting the Date & Time

Guides users through configuring the device's date and time using the slider and buttons.

Running a Built-in Programme

Explains how to use the pre-set programs after initial setup and date/time configuration.

Programming Your ST9400 A

Built-in Programmes

Presents default heating and hot water schedules (Profiles A, b, C) as starting points.

Your Personal Programme

Provides a template for users to record their own custom heating and hot water schedules.

Reviewing Programme Times

Describes how to check existing programmed ON and OFF times for heating and hot water.

Modifying the Hot Water Programme

Details the process for changing hot water ON/OFF times using the slider and buttons.

Programming Your ST9400 A (Continued)

Exiting HOT WATER Programming Mode

Explains how to save changes made to hot water settings and return to normal operation.

Modifying the Heating Programme

Guides users on setting heating ON/OFF times, following a similar procedure to hot water.

Disabling Enabling Time Periods

Explains how to turn specific ON/OFF periods on or off by setting start and end times to be the same.

Operating Your ST9400 A

Choosing the Operating Mode

Details the different operating modes (OFF, AUTO, ONCE, CONT) for heating and hot water.

Overriding the Operation

Explains how to temporarily change the heating or hot water status without altering the program.

The Extra Hour Function

Describes how to extend heating or hot water periods by one hour increments, up to three hours.

Fine Tuning Your ST9400 A

Changing Time Display Format

How to switch between 12-hour AM/PM and 24-hour clock display formats.

Changing Installer Parameters

Explains adjustable settings configured by an installer to suit lifestyle or preferences.

Entering Installer Mode

Step-by-step guide to access and navigate the installer settings menu.

Exiting Installer Mode

How to safely leave the installer configuration menu and return to normal operation.

FAQ and Troubleshooting

Setting the Time

How to correct the clock if it is not showing the accurate time.

Automatic Clock Adjustment

Explains the automatic summer/winter time change feature and how to manage it.

Programming Assistance

Advice for users who get 'lost' or confused while programming the device.

Power Failure Handling

Describes behaviour and recovery after a mains power outage, including data retention.

Troubleshooting Guide

Blank LCD Display

Diagnosing and resolving issues related to a blank screen on the programmer.

Radiators Cold No Hot Water

Troubleshooting symptoms when the system is ON but radiators are cold or hot water is not running.

INTERNAL FAULT Message

Addressing and resolving internal error messages displayed by the programmer.

NOT VALID Display

Explains why 'NOT VALID' might appear when selecting the HOT WATER position.

Mini-Programmer Operating Instructions

What is a Mini-Programmer?

Explains the specific functionality and limitations for mini-programmer setups.

Modifying Heating & Hot Water Programme

How to set schedules for heating and hot water when configured as a mini-programmer.

Exiting Mini-Programmer Mode

How to save settings and exit programming mode when configured as a mini-programmer.

Disabling Enabling Time Periods

Managing ON/OFF periods in mini-programmer mode by setting identical start and end times.

Mini-Programmer Operating Instructions (Continued)

Operating Mode Restrictions

Details restrictions on operating modes (e.g., AUTO heating, OFF hot water) for mini-programmers.

Override and Extra Hour Functions

Explains how override and extra hour functions behave in mini-programmer mode.

Configuration & Service Data

Configuration Data (Installer)

A table for the installer to complete, indicating how the ST9400A has been configured.