
Installation & Operating Instructions
7 Day Digital 
Time Switch
Model: NTT03 
Immersion Timer
Model: NTT04 
General Purpose Timer

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1. General:
This time switch is a compact and easy to use digital 
7 day timer, which fits on a single gang wall box. 
It can control outputs of up to 16A which makes it 
suitable for domestic immersion heaters.
The NTT04 has volt free contacts, making 
it suitable for a wider range of switching 
applications. The NTT03 is designed primarily  
for domestic immersion heaters.
Programming can be 7 day, 5 + 2, or 24 hour.
NTT03 – Immersion Timer 
NTT04 – General 
Purpose Timer
Power LED Output LED
Bezel 
fixing 
screws
Advance 
button
Boost 
button
BezelProgramme 
button
Illuminated 
screen
Reset 
button
Time 
button

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2. Features:
4 ON/OFF switching programmes,  
which can be made to operate over all 7 days  
(24 hour operation), 5 weekdays 2 weekend days, 
or any individual day (7 day operation).
Advance feature advances to next  
programmed operation.
Boost feature provides 1 or 2 hour boost. 
Battery back up retains programmes and clock 
times during loss of mains. 
Option of automatic summer time update (ASCO). 
Shortest switching time of 1 minute. 
Programme review.
3. Installation:
We recommend that this unit be fitted by a 
qualified electrician. Install in accordance 
to wiring and current building regulations. 
Please read the instructions carefully. If in 
any doubt contact the Timeguard Helpline.
Important: Switch off mains electricity 
before commencing work.
Remove the two bezel fixing screws, and remove 
bezel from timer module and back plate. Separate 
the timer module from the back plate, and remove 
the wall fixing screws.
Ensuring that the free terminals on the back plate 
are at the top, connect the installation wiring to 
the terminal block, according to the legend on the 
wiring label.
The earth wires should be connected to the wall 
box earthing terminal, or should be connected 
together using a single way connector block if 
there is no suitable earth terminal in the back box.

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4. Battery:
The time switch has a factory fitted rechargeable 
battery to give clock operation and programme 
memory back up during loss of mains supply.
Before programming for the first time, connect the 
unit to the mains for at least 15 minutes prior to 
pressing the Rst button and programming the unit.
If the display is not visible or very faint, charge for  
4 hours prior to pressing Rst and programming.
Fit the wall mounting screws through the back plate 
into the wall box threaded holes, and tighten until 
the back plate is firmly fastened.
Fit the timer module to the back plate, ensuring 
the power output indicator is on the top, and the 
locating holes on the timer are set correctly on the 
pegs on the back plate. Fit the bezel over the timer 
module, and secure to the back plate with the two 
screws provided.
For other wiring, the terminals are marked as follows:
L  Live supply 
N  Neutral supply 
N OUT Neutral output to immersion heater 
(NTT03 only).
SL  Switch live output to immersion heater 
(NTT03 only).
S in  Live Input for volt free output 
(NTT04 only) If volt free is not required,  
fit a link between L and S in.
S OUT Switch live output to heater or other 
appliance (NTT04 only).
Note: this device needs to be left to charge for  
a minimum of 15 minutes once powered up,  
before it will operate.

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5. Reset:
The time switch must be reset before programming for 
the first time, or after subsequent discharge for more 
than 5 days, and following a 4 hour period of charging.
Press Rst using a pointed object, eg: a pencil.  
The display will show all the 
segments, and then clear to show:
Use the Adv/Ovr button to change 
between on and off for the automatic 
summer time adjustment and  
proceed to section 6.
6. Setting the clock:
Press and hold down the Time 
button for 3 seconds. The word hold 
will show on the screen. 
After 3 seconds, the screen will 
show a year.
Use the Adv/Ovr or Boost buttons to 
change the year to the correct year.
Press Time to set the year, and then the 
month will show.
Use the Adv/Ovr or boost button to 
adjust the month to the correct month.
Press Time to set the month, and then the day will show.
Use the Adv/Ovr or boost button to 
adjust the day to the correct day. 
Press Time to set the day, and then 
the time will show, hours first.

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Use the Adv/Ovr or boost button to 
adjust the hour to the correct hour.
Press Time to set the hour, and  
then the time will show the minutes. 
The hour is a 24 hour clock. 
Use the Adv/Ovr or boost button  
to adjust the minutes to the  
correct minutes. 
Press Time to exit the Time/date 
entry mode.  
The display should now show the correct  
time/day of the week. 
Note: during time/date setting, when the Adv/Ovr 
or Boost buttons are held down, the setting under 
adjustment will advance or decrease more rapidly.
7. Modifying the date and 
time of day:
Normally the only change required 
will be to the time of day minutes, in 
which case press and hold Time for  
3 seconds, during which hold will 
show on the display. After 3 seconds 
the display will show the year: 
Press Time repeatedly until the minutes are shown. 
Use Adv/Ovr or Boost to change the minutes to the 
correct value. Press Time to return to operating mode. 
Other changes can be made the same way, but the 
Time button must be pressed to return to operating 
mode after any changes. There is no automatic exit 
from Time/date entry mode.

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8. Programming  
ON/OFF times:
The NTT03/04 has 4 independent ON/OFF periods 
available for programming each day. There is a choice 
of programming options, including 7 days the same 
(24 hours), 5 + 2 days (where the weekdays are the 
same, and the two weekend days are the same),  
and 7 individual days.
Press and hold the Prg button for  
3 seconds. Whilst holding, the word 
Hold should show on the display.
After 3 seconds, the mode screen 
will show. 
Use Adv/Ovr or Boost to change the day grouping 
mode. This will step through the following options:
24hr – Mo Tu We Th Fr Sa Su
5 day – Mo Tu We Th Fr followed automatically in 
programming by 2 day – Sa Su.
Individual day – Mo followed automatically in 
programming by each of the other days.
Once the desired day grouping is 
selected, press Prg to move onto 
programming ON/OFF times.  
The display will show Prog 1, with 
dashes for the hours and minutes. 
Example shown is for 5 + 2 programme.
Use Adv/Ovr or Boost to set the hour for the first ON 
period. Press Prg to change to setting the minutes.
Use Adv/Ovr or Boost to set the minutes.

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Press Prg to change to  
programme 1 OFF time.
Press Prg to scroll through 
programme 2 ON, programme 2 OFF, 
programme 3 ON, programme  
3 OFF, programme 4 ON and programme 4 OFF, 
adding in times as required.
If times are not required, just leave the dashes in 
place, and scroll past that programme.
After programme 4 has been entered, the day will 
index to the next day to be programmed, or in the 
case of 5 + 2 it will change to Sa Su. Programme the 
ON/OFF times as before.
After the last off time for programme 4 has been set, 
press Prg to exit programme mode.
At any stage in programming, if the 
Prg button is pressed and held for 
3 seconds, the timer will return to 
operating mode.
The display will now show: 
Where the day and time are correct,  
but the ON/OFF indicator may not reflect the current 
programme accurately, in which case press the Adv 
button to correct the indicator.
In the same way as for individual programmes, days 
or groups of days can be omitted either by leaving 
dashes in all the locations for ON/OFF times for 
that day or group of days. Alternatively, leaving the 
programme entry mode before filling in all the  
ON/OFF times will leave the remaining times blank.
The only way to re-enter a blank time is to reset 
the unit.

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8.2 Programming  
across midnight:
Enter the required programme ON time.
Enter the programme OFF time as 00:00
Enter the first programme ON time for the next day 
as 00:00
Enter the required programme OFF time. 
Note: for 24 hour the ON period for programme 1 
must start 00:00.
9. Modifying or  
adding programmes:
Press Prg and hold for 3 seconds. Whilst holding,  
the word hold will appear on the display.
After 3 seconds the display will show the 
programming mode screen. This will be in the mode 
in which it was last programmed. For instance if it 
was programmed in 5 + 2, then it will show Mo Tu 
We Th Fr. Either accept this, press Prg, and review the 
times programmed for this mode by pressing Prg, 
or press Adv/Ovr or Boost to change the mode, and 
then press Prg to review the times. In this case, either 
to Sa Su, or to 7 day or to individual days.
Note: If the unit was programmed as a 5 + 2 then 
changing the mode to any other mode other than  
Sa Su may blank any previous programming.
The same applies for changing from any other mode, 
changing from the mode it was last programmed in 
may blank the previous programme.
Review times and adjust as necessary as described 
in section 8.

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10. Advance/Override:
In operating mode Adv/Ovr advances the programme 
to the next change. If the output is OFF, it will change 
the output to ON, until the next programmed OFF 
time. If the output is ON, it will change the output to 
OFF, until the next programmed on time.
A second push of the Adv/Ovr button selects a 
permanently on mode, where the output is ON, 
irrespective of the programming.
A third push of the Adv/Ovr button selects a 
permanently OFF mode, where the output is OFF, 
irrespective of the programming.
A fourth push of the Adv/Ovr button returns the unit 
to operating mode, where the output will conform to 
the programming.
11. Boost:
One press of the boost button will provide 1 hours 
boost, after which the output will turn OFF. Two 
presses will give 2 hours boost. A third press of  
the boost button will cancel any boost period.

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12. Specifications:
Operating temperature:  0°C to 40°C
Operating voltage:  230V 50Hz
Switch rating:  16A resistive,  
    4A inductive, 
    0.55 HP,  
    750W incandescent,  
    750W halogen,  
    750W fluorescent,  
     100W compact fluorescent.
Minimum depth  
of wall box:  32mm
Switch type:  16A relay
Voltage free contact:  NTT04 only
Contact type:  Normally open
Power ON light:  Yes
Output Light:  Yes
Time period:  7 day
Note: 
Product not suitable for discharge lighting.

Zerofour – April 2013
67.058.480 (issue 2).
3 Year Guarantee
In the unlikely event of this product 
becoming faulty due to defective material 
or manufacture within 3 years of the date of purchase, 
please return it to your supplier in the first year with 
proof of purchase and it will be replaced free of 
charge. For years 2 and 3 or any difficulty in the first 
year telephone the helpline on 020 8450 0515. 
Note: a proof of purchase is required in all cases. For all eligible 
replacements (where agreed by Timeguard) the customer is responsible 
for all shipping/postage charges outside the UK. All shipping costs are 
to be paid in advance before a replacement is sent.
Timeguard Limited. 
Victory Park, 400 Edgware Road, 
London NW2 6ND
Sales Offi ce: 020 8452 1112
or email csc@timeguard.com
For a product brochure please contact:
For assistance with the product please contact:
or email helpline@timeguard.com
HELPLINE
020 8450 0515