Honeywell Home ST9400C 7-Days PROGRAMMABLE THERMOSTAT User Guide

Honeywell Home ST9400C 7-Days PROGRAMMABLE THERMOSTAT

PLEASE RESPEC T 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 ‘O ff’ time periods. Some models switch the central heating and domestic hot water on and off at the s ame 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 c hosen ‘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 Greenwi ch Mean Time and British Summer Time. You may be able to temporarily adjust the heating programme, for example, ‘Override’, ‘Adv ance’, or ‘Boost’. These are explained in the manufacturer’s instr uctions. 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.
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 Home reserves the right to modi fy 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 applicat ions as described within this document. For use outside of the scope as described herein, refer to Honeywell Home for guidance. Honeywell Home cannot be held responsible for misapplication of the product( s) described within this document.
Manufactured for and on behalf of the Env ironment and Combustion Controls Division of Honeywell Technologies Sàrl, ACS-ECC EMEA, Z.A. La Pièce 16, 1180 Rolle, Switzerland by its Authorised Representative Honeywell Inc.

Features

• Easy to use slider and buttons combined with ‘LoT’™ Technology and an ‘OK’ button, allows you to confirm 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 7-day Heating & Hot Water Programmes let you choose settings built into ST9400C 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 ST9400C every time.
• Built-in Memory holds your programme indefinitely – even if the mains power fails.

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 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 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.

ST9400C Controls Layout

1. Hot Water Operating Mode Indicator
2. Time Display
3. LoT™ Technology Display
4. Programme Time Markers
5. Day of Week Indicator
6. Heating Operating Mode Indicator
7. Heating Extra Hour Button
8. Heating Indicator Lamp
9. Heating Override Button
10. Slider
11. Heating Operating Mode Button
12. OK/Next Button
13. Clock – and + Buttons
14. Hot Water Operating Mode Button
15. Holiday Button
16. Copy Day Button
17. Next Day Button
18. Hot Water Override Button
19. Hot Water Indicator Lamp
20. Hot Water Extra Hour Button

Boiler & System Service Log

The space below can be used to provide a record of boiler & system services and the names and contact numbers of the Installer and Service Personnel.
This information is important for a Home Information Pack.

Service/Installation Date	Installation/Service Engineer	Telephone Number / Contact Details

WHAT IS A PROGRAMMER?

General Description
Your Honeywell Home ST9400C provides timing control for both your central heating and hot water systems, letting you set ON and OFF periods to suit your own lifestyle.
The ST9400C does not directly control the temperature but works together with other temperature controls, such as room thermostats and cylinder thermostats, to control your heating and hot water system in your home.
With 7-day programming and up to 3 on/off periods per day, every day can be set differently, and heating and hot water can be set at different times from each other.
The following instructions explain how to programme and use the ST9400C to provide the most home comfort at the least cost.

The way to use a Programmer
Think about the time periods when you are typically in the house and when you are not, and also the times when you use a lot of hot water. These are the times you should use as the basis for the programmes. It will be necessary to allow some heat-up time for the heating system after periods when it has been off – this would typically be 1 – 1½ hours, depending on your house and your preferences.
Other features are commonly available on the Programmer to enhance comfort and convenience, for example, OVERRIDE, EXTRA HOUR, and MODE buttons.
A typical use of the OVERRIDE feature is when you return home unexpectedly for the rest of the day and the heating is off. Just press the heating OVERRIDE button and the heating will come on until the next programme time, at which point it will follow the normal programme. The advantage here is that you do not have to remember to switch off because the normal time programme does this for you.
A typical use of the EXTRA HOUR button would be if you returned to the house for a short period when the heating and hot water were off. Pressing the appropriate EXTRA HOUR button gives you 1, 2, or 3 hours of heating, exactly when you need it. Another typical use is when the heating is already on and you want it to stay on a little longer – just press EXTRA HOUR and, for that day only, an hour will be added to the end of the time at which heating normally goes off.
The MODE buttons allow you to select how you want to operate heating and hot water independently. The most obvious use is to switch heating OFF during the summer months, but you may also use this feature if you take a mid-week day off work, you can then set the MODE to ONCE to keep the system ON during the day from the first programmed ON time till the last programmed OFF time.

GETTING STARTED WITH YOUR ST9400C
Your ST9400C should have been set up to work correctly when it was installed. However, the following will show you how you can modify your settings to meet your particular lifestyle.
To assist you with programming and everyday use your ST9400C will display text messages at every stage to help you get the most out of your central heating and hot water system. The ST9400C uses LoT™ Technology to constantly update the display to give you feedback about what is required.

Step 1: Setting the Date & Time
Your ST9400C had the date and time set at the factory, and these are normally maintained by a backup battery in the event of power failures. If you wish to change the date or time, or if the LoT™ Display shows the message ‘SET DATE + TIME’ just follow the instructions below. Otherwise, go to Step 2.

• Move the slider to the DAY/TIME position. The message ‘SET DATE + TIME’ will show briefly on the screen, followed by ‘SET THE DAY’, and the day of the month will now be flashing to indicate it can be changed.
• To change the day of the month, press the buttons until the correct day is shown. Each press of the button will change the date by one day. As soon as a change has been made, the message ‘IS DAY OK?’ will be displayed. Once the correct day is reached, press the greenbutton to confirm, and move to the next step. If you do not need to make a change, just press thebutton immediately and this will move you to the next step.
• The month digits will now be flashing and ‘SET THE MONTH’ will be displayed. To change the month, press thebuttons until the correct month is shown. The message ‘IS MONTH OK?’ will be displayed. Press the greenbutton to confirm the month is correct, and move to the next step.
• The year digits will now be flashing and ‘SET THE YEAR’ will be displayed. To change the year, press thebuttons until the correct year is shown. The message ‘IS YEAR OK?’ will be displayed. Press the green button to confirm the year is correct. If you have made a change, and the date is a valid date, the message ‘DATE SAVED’ will show, and you can move to the next step. If the date you set was not valid, for example 31 September, the message ‘INVALID’ will show and you will be returned to the start of the date setting operation.
• The time will now be flashing and the message ‘SET THE TIME’ will be displayed. To change the time, press the buttons until the correct time is shown. Each press of the button will change the time by one minute. Holding the button down for more than a few seconds will change the time slowly at first, then quickly. The message ‘IS TIME OK?’ will be displayed. Press the greenbutton to confirm the time is correct. If you have made a change, the message ‘TIME SAVED’ will show, followed quickly by ‘DATE + TIME COMPLETE’.
• Move the slider to the RUN position, to complete setting the date and time.
  Note: if the slider is moved at any time before the date and time have been set correctly, the message ‘DATE UNCHANGED’ will be displayed briefly, and your changes will not be saved.

Step 2: Running a Built-in Programme
With the date and time correct, your ST9400C Programmer will now be operating to the built-in programmes. These have been designed to provide heating and hot water at typical times throughout the day, but if you want to customise the settings, please see the next section ‘PROGRAMMING YOUR ST9400C’ (page 6).

PROGRAMMING YOUR ST9400C

The Built-in Programmes
The built-in programmes give you a starting point that you can personalise to your own requirements. Your Installer should have selected one and ticked the box alongside it. If there is no tick, the product normally leaves the factory with Profile A installed, but it is a simple matter to select one of the other profiles (see Changing the Installer Parameters, page 12).

Built-in Programme (Profile A)

		ON 1	OFF 1	ON 2	OFF 2	ON 3	OFF 3
Monday to Friday	Heating	6:30am	8:30am	12:00pm	1:00pm	4:30pm	10:30pm
	Hot Water	6:30am	8:30am	12:00pm	1:00pm	4:30pm	10:30pm
Saturday & Sunday	Heating	6:30am	9:30am	12:00pm	1:00pm	4:30pm	11:00pm
	Hot Water	6:30am	9:30am	12:00pm	1:00pm	4:30pm	11:00pm

Built-in Programme (Profile b)

		ON 1	OFF 1	ON 2	OFF 2	ON 3	OFF 3
Monday to Friday	Heating	6:30am	9:30am	12:00pm	1:00pm	4:30pm	11:00pm
	Hot Water	6:30am	9:30am	12:00pm	1:00pm	4:30pm	11:00pm
Saturday & Sunday	Heating	6:30am	9:30am	12:00pm	1:00pm	4:30pm	11:00pm
	Hot Water	6:30am	9:30am	12:00pm	1:00pm	4:30pm	11:00pm

Built-in Programme (Profile C) 

		ON 1	OFF 1	ON 2	OFF 2	ON 3	OFF 3
Monday to Friday	Heating	6:30am	7:30am	12:00pm	12:00pm	5:00pm	10:00pm
	Hot Water	6:30am	7:30am	12:00pm	12:00pm	5:00pm	10:00pm
Saturday & Sunday	Heating	8:30am	9:30am	12:00pm	1:00pm	5:30pm	10:30pm
	Hot Water	8:30am	9:30am	12:00pm	1:00pm	5:30pm	10:30pm

Your Personal Programme

The table below has been left blank for you to record your own personal programme.

		ON 1	OFF 1	ON 2	OFF 2	ON 3	OFF 3
Monday	Heating
	Hot Water
Tuesday	Heating
	Hot Water
Wednesday	Heating
	Hot Water
Thursday	Heating
	Hot Water
Friday	Heating
	Hot Water
Saturday	Heating
	Hot Water
Sunday	Heating
	Hot Water

Reviewing the Programme Times
To review your hot water programme, move the slider to the HOT WATER position.
To review your heating programme, move the slider to the HEATING position.
To review the programme times, press the button repeatedly. The appropriate ON and OFF markers will be displayed to show you which time is being reviewed. Any of these times can be adjusted by using the buttons, and then confirmed using the button. Remember to return the slider to the RUN position after reviewing is complete.

Modifying the Hot Water Programme
The hot water programme has three pairs of ON/OFF switching times per day. Each time can be set between 3.00 am and 2.50 am (on the next day) to allow you to programme the hot water to stay on past midnight, if required.

• Move the slider to the HOT WATER position. ‘SET HOT WATER’ will show briefly to verify this action.
• ‘SET ON-TIME 1’ will then be displayed and the time setting for the first ON 1 time for MONDAY will now be flashing to indicate it can be changed. If you do not wish to change the time, press the green button and move to the next step. If you do wish to make a change, use the buttons to change the first ON 1 time. Each press of the button will change the time by 10 minutes. As soon as the time has been changed, the message ‘ON-TIME 1 OK?’ will be displayed. Press the green button to confirm the time is correct and move to the next step. ‘SAVED’ will be displayed for a moment to confirm that any change has been saved to memory.Note: When pressing the button the next ON or OFF marker may start to flash. This indicates you have tried to set a time equal to one of the next programme times already in the memory. Similarly, when pressing the button the previous ON or OFF marker may start to flash. This indicates you have tried to set a time equal to one of the previous programme times. If this happens the ST9400C simply moves both times together as long as you continue to press thebuttons. Follow the procedure in ‘Reviewing the Programme Times’ (page 7) to check and adjust these times as necessary.
• ‘SET OFF-TIME 1’ will be displayed and the first OFF 1 time will now be flashing. If you do not wish to change the time, press the greenbutton and move to the next step. Otherwise, use thebuttons to change the time. Press the greenbutton to confirm the time is correct and move to the next step. ‘SAVED’ will be displayed for a moment to confirm that any change has been saved to memory.
• The remaining ON and OFF times (ON 2, OFF 2, ON 3, OFF 3) can be set by using the or buttons to change the time, and the greenbutton to confirm the time is correct and move to the next step. If you do not wish to change the time, just press the green button to move directly to the next ON/OFF time without making any changes.
• After setting or reviewing the last off time, OFF 3, the message ‘COMPLETE’ will be displayed to indicate the times for Monday have been set.
  You now have a choice of how to set the programme for the next day:
  Copying one day’s Programme to another day (example Monday to Tuesday):
• Whilst the day is showing Monday, Press the COPY DAY button. The message ‘COPY MON TO TUESDAY OK?’ will be displayed and the letters TUE will flash to indicate the programme for Monday can be copied to Tuesday.
• To select a different day to copy to, press the NEXT DAY button to cycle through the days. With each press of the NEXT DAY button the message will change to indicate the new day you are copying to.
• When the required day is indicated, press the greenbutton to confirm, and the message ‘MON COPIED’ will be displayed for a moment. The day into which Mondays programme has been copied is now available to have its programme edited.
  Note: Once a day’s programme has been confirmed in this way, it now becomes the day whose programme is copied if the COPY DAY button is pressed again.
  OR
  Programming a Different Day:
• Press the NEXT DAY button to select the next day, which is displayed along the top of the screen. The programme for that day can then be adjusted by following steps b – e above. Programmes for the remaining days can be set in the same way, using the NEXT DAY button to move to the next day.

Exiting HOT WATER Programming Mode:
To exit HOT WATER programming mode, move the slider to the RUN position. This can be done at any time during the programming process, and any changes made and confirmed with thebutton will have been saved.
Note: If the unit is left in HOT WATER Programming mode for more than 10 minutes without the slider being moved or any buttons pressed, the message ‘MOVE SLIDER’ will be displayed. Press a button to finish programming, or move the slider to the RUN position.

Modifying the Heating Programme
The heating programme has three pairs of ON/OFF switching times per day. Each time can be set between 3.00 am and 2.50 am (on the next day) to allow you to programme the heating to stay on past midnight, if required.

• Move the slide switch to the HEATING position. ‘SET HEATING’ will show briefly to verify this action.
• Now follow the same procedure to set the times as described in ‘Modifying the Hot Water Programme’ (page 7) steps b. to i.

Exiting HEATING Programming Mode: 
To exit HEATING programming mode, move the slider to the RUN position. This can be done at any time during the programming process, and any changes made and confirmed with the button will have been saved.
Note: If the unit is left in HEATING Programming mode for more than 10 minutes without the slider being moved or any buttons pressed, the message ‘MOVE SLIDER’ will be displayed. Press a button to finish programming, or move the slider to the RUN position.

Disabling / Enabling Time Periods (for Heating and/or Hot Water)
To disable any of the time periods ON 1 to OFF 1, ON 2 to OFF 2, or ON 3 to OFF 3, simply set the ON time and its paired OFF time to the same time, and the programme will just ignore them.
To re-enable the time period, simply set the two ON and OFF times to be different.

OPERATING YOUR ST9400C

Choosing the Operating Mode (for Heating and/or Hot Water)
The operating mode may only be changed when the slider is set to the RUN position. A green INDICATOR LAMP shows when the heating or hot water is switched ON.
Two MODE buttons are provided to select the Operating Mode and therefore how the heating and hot water are controlled. Heating has four possible Operating Modes; these are OFF, AUTO, ONCE, CONT. Pressing the heating MODE button scrolls round these modes in sequence, and the display indicates which mode is currently active.

• OFF mode
  The heating will remain OFF.
• AUTO (Automatic) mode
  The heating will be switched ON and OFF according to the heating programme.
• ONCE mode
  The heating will come ON at the first programmed ON time, and go OFF at the last programmed OFF time.
• CONT (Continuous) mode
  The heating will remain ON continuously.

The hot water MODE button operates in the same way as described above for the heating MODE button.

Overriding the Operation Without Changing the Programmes
In AUTO and ONCE operating modes, the OVERRIDE buttons switch the heating or hot water ON or OFF without altering the programme.
When the indicator lamp is ON, pressing the OVERRIDE button switches the heating or hot water OFF until the next programmed ON time.
When the indicator lamp is OFF, pressing the OVERRIDE button switches the heating or hot water ON until the next programmed OFF time.
The LoT™ Display will provide you with information about the override.

The Extra Hour Function (for Heating and/or Hot Water)
The EXTRA HOUR buttons allow you to switch the heating or hot water ON for up to 3 extra hours without altering the programme. Pressing either button once will give one extra hour. The LoT™ Display will display the message ‘+ 1 HOUR’, to confirm the button has been pressed.
When the green INDICATOR LAMP is OFF, pressing an EXTRA HOUR button switches the heating or hot water ON for just one hour.
When the green INDICATOR LAMP is ON, pressing an EXTRA HOUR button extends the programmed ON period by one hour.
Further presses of the EXTRA HOUR buttons will increase the extra hour period by one hour for each button press, up to a maximum of 3 hours. The LoT™ Display will continue to provide information on the extra hour status.
To cancel the extra hours, just keep pressing the EXTRA HOUR button until the ‘CANCELLED’ message appears on the LoT™ Display.

The Holiday Function

The Holiday function allows you to switch off your heating and hot water for a specified number of days (from 1-99 days). This lets you save energy and related costs when you are away from home, but resumes normal operation on the day of your return.
To set the Holiday function:

• Ensure the slider is in the RUN position, then press the HOLIDAY button once. The message ‘SET HOLIDAY’ will appear briefly, followed by ‘SET DAYS AWAY’.
• Use the buttons to set the number of days you will be away. The display will show the number of days, and this number will be flashing to indicate it can be changed. The day of the week will also keep changing to show the day you return.
• If you have made a change to the number of days, the message ‘DAYS AWAY OK ?’ will appear. Press the green button to confirm your selection.
• The message ‘SAVED’ will be displayed for a few seconds, followed by the date you return, to enable you to check you have programmed the holiday function correctly.
• During the holiday period, the LoT™ Display will show the message ‘ON HOLIDAY’ and the display will count down the number of days till you return.

To cancel the Holiday function: 

• To cancel the Holiday function, just press the HOLIDAY button again. The LoT™ Display will show ‘CANCELLED’ and the unit will return to normal operation.
  Note: while setting the Holiday function, if there is a gap of more than 1 minute between button presses, the function will cancel itself automatically and return to normal operation.

FINE-TUNING YOUR ST9400C

Changing from AM/PM Time Display to the 24 Hour Clock
Your ST9400C can operate on the 12 hour AM/PM or 24 hour clock formats. To change the format, ensure the slider is in the RUN position then press and hold the buttons together for about 2 seconds. Ignore the ‘NOT VALID’ message that will appear briefly. All the displayed times will be automatically changed to the new format.
Repeating this procedure will change the clock display back to the original format.

Changing the Installer Parameters
The ST9400C has a special Installer Mode where some features can be adjusted to suit your lifestyle or preferences – these are called Installer Parameters, and are listed in the table below, along with a description of the options that are possible.

INSTALLER PARAMETER	Parameter Number	Default Value	Options	Description
24hr or am/pm clock display.	1	12	12, 24	12 = am/pm display, 24 = 24hr display
Configure backlight operation.	2	2	0, 1, 2	0 = off, 1 = on if button pressed, 2 = on continuously
Enable/disable auto time change.	3	1	0, 1	0 = disabled, 1 = enabled
1-day or 5/2-day or 7-day operation.	4	7	1, 5, 7	1 = 1-day operation, 5 = 5/2-day operation, 7 = 7-day operation
Number of ON/OFFs per day.	5	3	2, 3	2 = 2 on/offs per day, 3 = 3 on/offs per day
Select default time programme.	6	A	A, b, C	A = standard, b = at home, C = economy
Configure Mini-Programmer.	7	0	0,1	0 = standard Programmer, 1 = Mini-Programmer
This will be set by your Installer and will depend on your system – do NOT change it without contacting the installer.
Reset all parameters	8	1	0, 1	0 = do not reset 1 = default parameters

To Enter Installer Mode: 

• Ensure the slider is in the RUN position, then press and holdand buttons together for 8 seconds. Ignore the ‘NOT VALID’ message that is displayed for a few seconds. The message ‘SET UP MENU’ will show briefly, followed by ‘SET INSTALLER OK ?’
• Press thebutton to take you into the Installer Mode Parameter Menu.
• Parameter 1 is now available to change. This is to allow you to change the clock format from 12 hour AM/PM to 24 hour. At every step, the LoT™ Display will inform you what the parameter means and what option you have selected. The parameter number is shown on the display separated by a colon from the parameter value.
• You can change the parameter value by pressing the buttons. At this point the description in the LoT™ Display will change and the parameter value will flash. If you press the value will stop flashing and be saved for use.
• Press to move to the next parameter available for editing.
• Keep pressingto step around the list of parameters, and usebuttons to change the parameter value.
• Any parameter changes that have been confirmed with the button will be saved and used.

To Exit Installer Mode: 

• You can exit Installer Mode at any time by moving the slider to the next position and then back again to RUN.
  Note: Installer Mode will exit automatically after 10 minutes if the slider is not moved.

FAQ AND TROUBLESHOOTING

How do I set the time only, if the ST9400C clock is not correct?
Your ST9400C contains a very accurate digital clock that is factory pre-set. Should you ever need to change the time, just follow this procedure:

• Move the slider to the DAY/TIME position.
• Keep pressing the green button until the message ‘SET THE TIME’ is displayed. To change the time, press thebuttons until the correct time is shown. The message ‘IS TIME OK?’ will be displayed. Press the green button to confirm the time is correct. If you have made a change, the message ‘TIME SAVED’ will show, followed quickly by ‘DATE + TIME COMPLETE’.
• Move the slider to the RUN position, to complete changing the time.

What do I do when the clocks go back in October and forward in March?
Your ST9400C is factory-set to adjust the clock automatically at the correct dates, so you should never need to adjust the clock forward or backwards yourself. It is possible to disable this particular feature, as described in the section ‘Changing the Installer Parameters’ (page 12). You may also check the section ‘Configuration & Service Data’ (page 18) to see how your Installer has configured your product.

What should I do if I get ‘lost’ while programming the ST9400C?
The LoT™ Display on ST9400C will provide you with help and tips to work through the programming. Should you ever get ‘lost’, the simplest thing to do is to move the slider to the RUN position, and then move it back to the appropriate programming position where you got lost. At this point just follow the instructions again.

What happens if there is a power failure?
In the event of a mains power failure, the ST9400C display will go blank, the indicator lamps will go out, and the control outputs will switch off. The real time will be constantly maintained by means of the built-in battery backup, ready to power back up as if nothing had happened when the mains power is restored. In addition, all programmes and settings are stored in a special memory (called NV memory) which requires no power to maintain information, and so will be retained indefinitely.
Should the correct time and date ever be lost, for whatever reason, the message ‘SET DATE + TIME’ will be displayed whilst the slider is in the RUN position. In this case, simply follow the procedure described under ‘Step 1: Setting the Date & Time’ (page 4). It should not be necessary to make any changes to your programmes.

Troubleshooting Guide

This is a quick guide to help you diagnose and cope with possible problems with ST9400C. For further assistance, please contact your Installer.

Symptom	Possible Cause	Remedy
ST9400C has a blank LCD display	No power to the heating system	Check that there is power to the heating system
	Fault in ST9400C	Call Installer
ST9400C indicates	Temperature controls	Check that the temperature controls
that Heating and/or	are switched off or set	in the system are set to appropriate
Hot Water are ON, but	too low	levels
radiators are cold and/
		Call Installer
or taps are running with cold water.	Boiler or other system controls have
	malfunctioned
ST9400C shows the message ‘INTERNAL FAULT’	Fault in ST9400C	Call Installer
When the slider is moved to the HOT WATER position, the display shows ‘NOT VALID’	ST9400C has been configured as a Mini-Programmer	Check the Contents page of this booklet or the ‘Configuration & Service Data’ section (page 18) to see if your ST9400C has been configured as a Mini-Programmer.
		Call Installer to check if this is correct for your heating system.

MINI-PROGRAMMER OPERATING INSTRUCTIONS

You need only refer to this section if: 

• The Mini-Programmer box is ticked on the Contents page of this booklet, or
• The ST9400C Configuration Data (page 18) indicates it is set as a Mini-Programmer.

What is a Mini-Programmer?
In a poorly controlled gravity circulation hot water system, whenever the boiler comes on to service the heating, there will inevitably be some circulation though the hot water storage tank, which will then heat up.
So, whenever the HEATING is ON, the HOT WATER is also ON.
It is therefore NOT possible to have independent programmes for heating and hot water, so it is only necessary to enter one time programme.
If you have this type of installation (gravity circulation hot water circuit WITHOUT a hot water control valve), your Installer should have restricted the ST9400C Programmer to be a Mini-Programmer.
This section describes how to use the product as a Mini-Programmer.

Modifying the Heating & Hot Water Programme
The heating & hot water programme has three pairs of ON/OFF switching times per day. Each time can be set between 3.00 am and 2.50 am (on the next day) to allow you to programme the heating & hot water to stay on past midnight, if required.

• Move the slider to the HEATING position. ‘SET HEATING’ will show briefly to verify this action.
• Now follow the same procedure to set the times as described in ‘Modifying the Hot Water Programme’ (page 7) steps b to i.

Exiting Heating & Hot Water Programming Mode:
To exit HEATING Programming mode, move the slider to the RUN position. This can be done at any time during the programming process, and any changes made and confirmed with the button will have been saved.
Note: If the unit is left in HEATING Programming mode for more than 10 minutes without the slider being moved or any buttons pressed, the message ‘MOVE SLIDER’ will be displayed. Press a button to finish programming, or move the slider to the RUN position.

Disabling / Enabling Time Periods
To disable any of the time periods ON 1 to OFF 1, ON 2 to OFF 2, or ON 3 to OFF 3, simply set the ON time and its paired OFF time to the same time, and the programme will just ignore them.
To re-enable the time period, simply set the two ON and OFF times to be different.

Choosing the Operating Mode
In a Mini-Programmer, some Operating Modes are not possible. For example, HEATING in AUTO mode and HOT WATER in OFF mode is not allowed. When configured, your ST9400C knows which combinations of Operating Mode are possible, and only permits those combinations that are allowed.

Override and Extra Hour Functions
When you use the hot water OVERRIDE or EXTRA HOUR functions, they will operate as normal. However, the heating OVERRIDE or EXTRA HOUR functions will also bring on the hot water. This is a consequence of the type of system you have, and is perfectly normal.

Other Functions
All other functions operate the in the same way as for the standard ST9400C.

CONFIGURATION & SERVICE DATA

Configuration Data (to be completed by Installer)
The table below is for the Installer to complete to indicate how your ST9400C has been configured.

Configurable Features	Options	Installer Configured (tick appropriate box)
24hr or am/pm clock display	am/pm display
	24hr display
Display backlight operation	Off
	On if button pressed
	On continuously
Automatic time change	Enabled
	Disabled
1-day or 5/2-day or 7-day operation	1-day operation
	5/2-day operation
	7-day operation
Number of ON/OFFs per day	2 on/offs per day
	3 on/offs per day
Default programme	A = standard
	b = at home
	C = economy
Set as Mini-Programmer *	No
	Yes

Note: It is recommended that gravity circulation hot water systems are fitted with a suitable hot water control valve as shown in the Honeywell Home Sundial C Plan system (see ST9400A/ST9400C Installation Instruction sheet). If so, then there is no need to set the ST9400C as a Mini-Programmer.

Reference

Download manual:

 Honeywell Home ST9400C 7-Days PROGRAMMABLE THERMOSTAT User Guide

OTHER MANUALS:

Honeywell Home ST9400C 7-Days PROGRAMMABLE THERMOSTAT INSTALLATION INSTRUCTIONS

Honeywell Home ST9400C 7-Days PROGRAMMABLE THERMOSTAT User Guide