Table of Contents

Advertisement

Quick Links

PLEASE RESPECT YOUR ENVIRONMENT!
Take care to dispose of this product and any
packaging or literature in an appropriate way
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.
WHAT IS A ROOM THERMOSTAT?
...an explanation for Householders (as recommended by the Energy Savings Trust)
A room thermostat simply switches the heating system on and off as necessary. It works by sensing
the air temperature, switching on the heating when the air temperature falls below the thermostat
setting, and switching it off once this set temperature has been reached. Turning a room thermostat to
a higher setting will not make the room heat up any faster. How quickly the room heats up depends on
the design of the heating system, for example, the size of boiler and radiators. Neither does the setting
affect how quickly the room cools down. Turning a room thermostat to a lower setting will result in the
room being controlled at a lower temperature, and saves energy. The heating system will not work if a
time switch or programmer has switched it off. The way to set and use your room thermostat is to find
the lowest temperature setting that you are comfortable with, and then leave it alone to do its job. The
best way to do this is to set the room thermostat to a low temperature – say 18ºC – and then turn it up
by one degree each day until you are comfortable with the temperature. You won't have to adjust the
thermostat further. Any adjustment above this setting will waste energy and cost you more money.
If your heating system is a boiler with radiators, there will usually be only one room thermostat to
control the whole house. But you can have different temperatures in individual rooms by installing
thermostatic radiator valves (TRVs) on individual radiators. If you don't have TRVs, you should choose
a temperature that is reasonable for the whole house. If you do have TRVs, you can choose a slightly
higher setting to make sure that even the coldest room is comfortable, then prevent any overheating
in other rooms by adjusting the TRVs.
Room thermostats need a free flow of air to sense the temperature, so they must not be covered by
curtains or blocked by furniture. Nearby electric fires, televisions, wall or table lamps may prevent the
thermostat from working properly.
Ademco 1 GmbH
@2020 Resideo Technologies, Inc. All
Hardhofweg 40
rights reserved The Honeywell Home
74821 Mosbach
trademark is used under license from
Phone: +49 1801 466 388
Honeywell International Inc. This product is
info.de@resideo.com
manufactured by Resideo Technologies,
homecomfort.resideo.com
Inc and its affiliates.
www.resideo.com
User Guide
2
Y9420H Sundial RF
Pack 2
How to use:
ST9420C Wireless Enabled Programmer
DT92E Wireless Room Thermostat
This document is to be left with the user
and forms part of a Home Information Pack
System Components
This section is to be completed by the Installer
Location
ST9420C
DT92E
(typically in living room or hallway)
Energy Efficiency 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 figure, so it is important to understand how your
controls can help to maximize energy efficiency 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
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 50 - 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 fit 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.
be

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the DT92E and is the answer not in the manual?

Questions and answers

Summarization of Contents

System Components
ST9420C Programmer
Wireless Enabled Programmer for central heating and hot water.
DT92E Room Thermostat
Wireless room thermostat for temperature control.
Energy Efficiency and Environment
General Energy Saving Tips
Tips for maximizing energy efficiency and comfort with heating controls.
Controls Layout Overview
ST9420C and DT92E Controls
Diagrams and labels for programmer and thermostat buttons and displays.
Boiler & System Service Log
Service Record Entry
Section for installers to record system service history and contact details.
Control of Your System
System Controls Description
Overview of the ST9420C programmer and its function with other controls.
Using the Programmer
Guidance on setting heating and hot water ON/OFF periods based on lifestyle.
Using the Room Thermostat
Instructions for setting the room thermostat for optimal comfort and energy saving.
Optimisation Features
Energy Saving Optimisation
Explanation of features like Optimum Start, Delayed Start, and Optimum Stop for energy saving.
Getting Started with ST9420C
Setting the Date & Time
Procedure for setting the correct date and time on the ST9420C programmer.
Running Built-in Programmes
Operating with Pre-set Programmes
How to operate the ST9420C using its pre-set programmes.
Programming Your ST9420C
Built-in Programme Options
Overview of pre-set heating and hot water programmes available.
Personal Programme Setup
Template for recording custom heating and hot water time schedules.
Modifying Programme Times
Reviewing Programme Times
How to check current heating and hot water programme settings.
Modifying Hot Water Programme
Step-by-step guide to changing hot water ON/OFF times.
Copying and Programming Days
Copying One Day's Programme
Method to copy one day's settings to other days for easier programming.
Programming Different Days
Instructions for setting programmes for individual days.
Modifying Heating Programme
Changing Heating Times
Step-by-step guide to changing heating ON/OFF times.
Managing Time Periods
Disabling/Enabling Time Periods
How to turn specific heating or hot water time periods on or off.
Operating Your ST9420C
Choosing Operating Mode
Selecting between AUTO, ONCE, CONT, or OFF modes for heating and hot water.
Overriding Operation
Temporarily switching heating/hot water on or off without altering programmed times.
Extended Functions
Extra Hour Function
How to extend heating or hot water run times by 1, 2, or 3 hours.
Holiday Function
Setting the system to an energy-saving mode for a specified period when away from home.
Enquiry Mode
Viewing System Information
Accessing and viewing temperature information from system components.
Fine Tuning ST9420C
Clock Format Settings
Switching between 12-hour and 24-hour clock formats on the ST9420C.
Installer Parameters
Adjusting advanced settings and preferences via Installer Mode.
Installer Mode Access
Entering Installer Mode
Steps to access the installer configuration menu for advanced settings.
Exiting Installer Mode
How to safely exit the installer configuration menu.
Optimisation Explained
Optimisation Diagrams
Illustrations of Optimum Start, Delayed Start, and Optimum Stop functionality.
Boiler Service Reminder
Service Countdown
ST9420C displays a countdown indicating when the next boiler service is due.
Service Overdue Alerts
Alerts and actions required when the boiler service is overdue.
Boiler Service Shut-down
System Shut-down Procedure
Procedure when the boiler service is overdue and the system automatically shuts down.
Operating Your DT92E
Inquiring and Adjusting Set Temperature
How to view and change the desired room temperature using the DT92E thermostat.
DT92E Operation Details
Switching Off DT92E
How to put the DT92E thermostat into standby or off mode.
Display Indicators
Meaning of display updates, heating indicator, and frost protection symbol.
DT92E Indicators and Lockout
Low Battery and RF Communication
Identifying low batteries and understanding RF communication status.
Lockout Functionality
Explanation of the lockout symbol and its implications for overriding settings.
DT92E Energy Saving ECO Feature
Entering and Using ECO Mode
How to activate ECO mode and set the duration for energy saving.
ECO Mode Behaviour
How the DT92E display shows ECO mode status and allows temperature adjustment.
Exiting ECO Mode
Deactivating ECO Mode
Procedure to deactivate ECO mode and return to normal operation.
Fine Tuning DT92E Installer Parameters
Changing DT92E Installer Parameters
Adjusting advanced settings for the DT92E thermostat via Installer Mode.
DT92E Installer Mode Operations
Entering and Exiting Installer Mode
Steps to access and safely exit the DT92E installer configuration menu.
Selecting and Changing Parameters
Navigating and modifying parameters within the DT92E installer menu.
FAQ and Troubleshooting
ST9420C Clock and Programming Issues
Resolving issues with setting time, DST, and getting lost during programming.
Power Failure and System Behaviour
How the ST9420C handles power failures and retains settings.
RF Communication Troubleshooting
RF Communication Reliability and Loss
Information on RF communication robustness and steps for resolving signal loss.
DT92E Battery and Override Issues
Identifying low batteries and overriding settings from the DT92E thermostat.
Troubleshooting Guide: ST9420C Issues
Blank Display and No Heat/Hot Water
Resolving blank display, no heat, or no hot water issues.
Internal Fault and Service Due
Addressing internal faults, service countdowns, and overdue service alerts.
Troubleshooting Guide: DT92E and Communication Issues
Sensor Faults and Low Battery
Resolving sensor faults, low battery messages, and blank DT92E displays.
Communication Loss and Signal Issues
Fixing 'NO SIGNAL' messages, RF symbol issues, and signal blocking.
Configuration and Service Data
Installer Configuration Data
Installer to record ST9420C and DT92E configuration settings for future reference.

Table of Contents

Save PDF