Intermatic DT122K Manual: A Comprehensive Guide
This comprehensive guide details the Intermatic DT122K, a 15 Amp 7-Day Indoor Digital Timer, offering setup and programming instructions via PDF downloads․
Overview of the Intermatic DT122K Timer
The Intermatic DT122K is a versatile, heavy-duty digital timer designed for indoor use․ This 7-day programmable timer features two 3-prong plugs and a 15 Amp capacity, making it suitable for controlling a variety of electrical devices․ It’s a popular choice for automating lighting, fans, and other appliances, offering convenience and potential energy savings․
Manufactured by Intermatic, a trusted brand in timer technology, the DT122K boasts multiple operation modes – manual, auto, and random – providing flexibility to match diverse scheduling needs․ Users can easily set ON/OFF events, and even utilize astronomical mode for sunrise/sunset-based control․ Installation is straightforward, being a plug-in model, and detailed instructions are available online as a PDF download (TM-087)․
The timer’s origin is China, and it comes with a 1-year warranty․ It’s designed for ease of use, with clear button navigation, as demonstrated in available video tutorials․
Key Features and Specifications
The Intermatic DT122K distinguishes itself with several key features․ It’s a 7-day programmable timer, offering granular control over scheduling․ Its dual 3-prong plugs allow simultaneous control of two devices, maximizing utility․ Operation modes include manual override, fully automatic scheduling, and a random mode for enhanced security simulation․
Specifications include a 15 Amp, 125 VAC, 60Hz rating, and a maximum load of 1875 Watts․ The timer operates indoors only and features a robust digital display for easy programming and time viewing․ The UPC code is 078275143395, and the model number is clearly identified as DT122K․
Further, the DT122K supports astronomical mode, adjusting schedules based on sunrise and sunset times․ Detailed instructions and a PDF manual (DT121K/DT122K) are readily available for download, ensuring a smooth user experience․ It’s built for reliability with a 1-year warranty;

Understanding the Timer Display
The DT122K features a digital display showcasing current time, day, and programmed settings; understanding display icons and button functions is crucial for operation․
Display Icons and Their Meanings
The Intermatic DT122K timer’s display utilizes several icons to communicate its current status and programmed functions․ Recognizing these symbols is essential for effective operation and troubleshooting․ A solid “ON” indicator signifies the timer is actively supplying power to the connected device, overriding any scheduled events when in Manual ON mode․ Conversely, an “AUTO” icon confirms the timer is operating according to the programmed schedule․
A flashing “PROGRAM” icon indicates the timer is in the programming mode, allowing users to modify ON/OFF events or adjust settings․ The “RANDOM” icon, when illuminated, signifies the timer is operating in random mode, providing simulated occupancy for security purposes․ The “ASTRONOMICAL” icon denotes the use of calculated sunrise and sunset times for automated control․

Furthermore, a day-of-the-week indicator clearly displays the current day, aiding in schedule verification․ Any error codes displayed will require referencing the troubleshooting section of this manual for resolution․ Understanding these icons empowers users to quickly assess the timer’s state and make necessary adjustments․
Button Functions and Navigation
Navigating the Intermatic DT122K timer is achieved through a series of dedicated buttons․ The “PROGRAM” button is central, initiating and exiting the programming mode for setting ON/OFF events․ “HOUR” and “MINUTE” buttons facilitate precise time adjustments, crucial for accurate scheduling․ “DAY” allows selection of the desired day(s) for event activation․
The “MODE” button cycles through the operational modes: Manual, Auto, and Random, offering flexibility in timer control․ Pressing “ON/OFF” in Manual mode directly overrides the programmed schedule, providing immediate power control․ A video introduction demonstrates button navigation, simplifying the learning process․
To review or change ON/OFF events, users press “PROGRAM” to access the event screens․ Careful button presses are required to avoid unintended changes․ Familiarizing yourself with these functions ensures efficient and accurate timer operation, maximizing its benefits․

Installation and Setup
The Intermatic DT122K is a plug-in timer for indoor use․ Initial setup requires a standard power connection, ensuring proper functionality and ease of installation․
Initial Setup and Power Connection
Before operating the Intermatic DT122K, carefully unpack the timer and inspect it for any damage․ Ensure the unit is free from defects before proceeding with installation․ This timer is designed for indoor use only and should not be exposed to moisture or extreme temperatures․

To begin, locate a standard electrical outlet․ The DT122K features a plug-in design, simplifying the power connection process․ Simply insert the timer’s plug directly into the outlet․ Then, plug the appliance you wish to control into one of the two 3-prong plugs on the timer itself․
Important Note: Verify that the appliance’s voltage and wattage requirements are compatible with the timer’s specifications (15 Amp, 125VAC)․ Overloading the timer can cause damage or create a safety hazard․ Avoid using extension cords or adapters during installation․ Ensure a secure connection to prevent accidental disconnections․
Setting the Current Date and Time
Accurate date and time settings are crucial for the Intermatic DT122K timer to function correctly, especially when utilizing the 7-day programming or astronomical mode․ To set the current date and time, begin by pressing the “PROGRAM” button․ This will initiate the setup sequence․
Next, use the “HOUR” and “MINUTE” buttons to adjust the current time․ Pay close attention to the AM/PM indicator to ensure the correct time of day is selected․ Once the time is set, press “PROGRAM” again to move to the date setting․ Use the same “HOUR” and “MINUTE” buttons – these also control the month and day – to set the current date․
Finally, press “PROGRAM” one last time to confirm your settings and exit the date/time setup․ The display will now show the correctly configured date and time, ensuring your programmed events activate at the intended times․
Programming the DT122K Timer
The DT122K allows for flexible programming, including manual override, setting specific ON/OFF events, and utilizing the convenient auto mode for scheduled operations․

Manual Override Mode
The Intermatic DT122K timer features a straightforward Manual Override mode, providing immediate control over the connected devices․ When activated, this mode temporarily suspends the programmed schedule, allowing you to switch the outlet ON or OFF regardless of the preset timings․
To engage Manual Override, simply press the “ON” or “OFF” buttons on the timer’s face․ The display will typically indicate that the override is active, often with a specific icon or text․ This allows for instant operation, bypassing the automated schedule for immediate needs․
Importantly, the Manual Override is typically temporary․ The timer will revert to its programmed schedule at the next scheduled event․ Understanding this temporary nature is crucial for maintaining consistent automated control․ The override function is ideal for situations requiring immediate adjustments without altering the long-term programming of the DT122K․
Setting ON/OFF Events
The Intermatic DT122K allows precise control through setting individual ON/OFF events․ To begin, press the “PROGRAM” button to access the event programming screens․ You’ll then navigate through the days of the week, setting specific times for the outlet to turn ON and OFF․
Typically, you’ll set the hour and minute for each event, confirming each entry․ The timer supports multiple ON/OFF cycles per day, offering a highly customizable schedule․ Reviewing your settings is crucial; ensure the times accurately reflect your desired operation․
The process involves selecting the day, then setting the ON time, followed by the OFF time․ Repeat this for each day and desired event․ Remember to save your changes after completing the programming․ This feature is central to the DT122K’s functionality, enabling automated control of connected devices based on your specific needs․
Using the Auto Mode
Auto Mode on the Intermatic DT122K activates the programmed schedule you’ve previously established․ After setting your desired ON/OFF events for each day, selecting “AUTO” enables the timer to follow this schedule automatically․ The display will typically indicate “AUTO” is active, confirming the programmed settings are in effect․
In Auto Mode, the timer operates independently, switching the connected device ON and OFF at the designated times without requiring manual intervention․ This is ideal for consistent, recurring schedules, such as lighting or appliance control․
If you need to temporarily override the schedule, utilize the “MANUAL” mode․ Returning to “AUTO” will resume the programmed operation․ Ensure the correct date and time are set for accurate scheduling within Auto Mode․ This mode provides convenient, hands-free operation based on your pre-defined preferences․
Advanced Programming Options
The Intermatic DT122K offers Random Mode for security simulation and Astronomical Mode, adjusting ON/OFF times based on sunrise and sunset data․
Random Mode Functionality
Random Mode on the Intermatic DT122K timer enhances security by simulating occupancy when you are away from home․ This feature randomly turns devices ON and OFF within a user-defined timeframe, making it appear as though someone is present․ To activate Random Mode, navigate through the programming settings using the timer’s buttons․ You’ll need to specify a start and end time for the randomization period․
The timer will then randomly activate and deactivate the connected devices during those hours, varying the ON times each day․ This unpredictability is key to deterring potential intruders․ It’s particularly useful for controlling lights, radios, or televisions․ Remember to consider the typical usage patterns of the devices you’re controlling to make the randomization seem more realistic․ The DT122K’s Random Mode provides a simple yet effective layer of home security, offering peace of mind while you’re traveling or away for extended periods․
Astronomical Mode Explained

Astronomical Mode on the Intermatic DT122K timer automatically adjusts ON/OFF times based on the calculated sunrise and sunset for your specific location․ This eliminates the need for manual adjustments throughout the year, especially beneficial for outdoor lighting․ Initial setup requires entering your geographical location – typically latitude and longitude – into the timer’s settings․ The DT122K then uses this data to determine the precise sunrise and sunset times each day․
You can define an offset, allowing you to schedule lights to turn on before sunset or off after sunrise․ This feature is ideal for landscape lighting, holiday decorations, or any application where timing needs to align with natural daylight․ The timer continuously updates these times, ensuring accurate operation even with changing seasons․ Utilizing Astronomical Mode provides convenient, energy-efficient control, adapting to the natural light cycle without requiring constant user intervention․
Troubleshooting Common Issues
Common issues with the Intermatic DT122K include failing to turn on/off or display errors; resetting to factory defaults can often resolve these problems․
Timer Not Turning On/Off
If the Intermatic DT122K timer isn’t switching as programmed, first verify the power connection is secure and the outlet is functioning correctly․ Double-check the programmed ON/OFF events, ensuring they align with the desired schedule and haven’t been accidentally overwritten․ Confirm the timer isn’t in ‘Manual ON’ mode, as this overrides automatic programming, keeping the device perpetually powered․
Inspect the load connected to the timer; an overloaded circuit or faulty appliance can prevent operation․ Ensure the appliance’s power requirements don’t exceed the timer’s 15 Amp capacity․ If using ‘Auto’ mode, confirm the current date and time are accurately set, as this is crucial for astronomical or schedule-based functions․ A reset to factory defaults, followed by reprogramming, can often resolve unexplained operational failures․ Finally, consult the Intermatic DT122K installation and user instructions PDF for detailed troubleshooting steps․
Display Errors and Solutions
Encountering errors on the Intermatic DT122K display often indicates a configuration issue or potential malfunction․ While specific error codes aren’t extensively detailed in readily available resources, a blank or flashing display typically suggests a power supply problem or internal timer fault․ If the display shows garbled characters, a reset to factory defaults – often involving a specific button combination detailed in the Intermatic DT122K manual – is the first step․
If the display remains unresponsive after a reset, the timer may require professional servicing or replacement․ Incorrect date/time settings can also cause unexpected behavior, so verify these are accurate․ Refer to the downloaded PDF installation and user instructions for guidance on navigating the display and interpreting any visible indicators․ Remember Intermatic does not accept liability for consequential damages․
Resetting the Timer to Factory Defaults
Resetting the Intermatic DT122K to its factory default settings clears all programmed schedules and returns the timer to its original configuration․ While the exact procedure isn’t universally documented across all resources, it generally involves a specific sequence of button presses․ Typically, holding the ‘Program’ and ‘Mode’ buttons simultaneously for a defined period – often several seconds – initiates the reset process․
Consult the Intermatic DT122K manual (available as a PDF download) for the precise button combination and duration, as variations may exist․ After a successful reset, you’ll need to re-enter the current date and time, and reprogram all desired ON/OFF events․ This is useful for troubleshooting persistent issues or preparing the timer for a new application․ Intermatic provides a one-year warranty, but resetting doesn’t cover misuse․
Safety Precautions and Warnings

Always follow electrical safety guidelines when installing and using the Intermatic DT122K․ Intermatic is not liable for damages resulting from improper use or installation․
Electrical Safety Guidelines
Prioritize safety during installation and operation of the Intermatic DT122K timer․ Ensure power is disconnected at the breaker before any wiring or connection attempts․ Never attempt to repair the timer yourself; contact a qualified electrician for service․
Avoid using the timer in damp or wet locations, as this poses a significant electrical hazard․ Do not exceed the timer’s 15-amp maximum load capacity to prevent overheating and potential fire risks․ Inspect the power cord regularly for damage, and replace it immediately if any wear or tear is detected․
Always ensure the outlet is properly grounded․ Use only with grounded outlets and extension cords․ Keep the timer away from flammable materials․ Remember, Intermatic disclaims responsibility for incidents caused by disregarding these crucial safety precautions․ Follow all local electrical codes and regulations․
Warranty Information

Intermatic provides a limited warranty for the DT122K timer, covering defects in materials and workmanship․ The standard warranty period is one year from the date of original purchase․ Proof of purchase is required for all warranty claims․ This warranty does not cover damage resulting from misuse, abuse, neglect, accidents, or unauthorized modifications․
The warranty specifically excludes consequential or incidental damages․ Intermatic’s liability is limited to the repair or replacement of the defective timer, at their discretion․ To initiate a warranty claim, contact Intermatic customer support with details of the issue and proof of purchase․

Returned products must be shipped prepaid to a designated Intermatic service center․ Warranty service performed by unauthorized personnel will void the warranty․ See the full warranty details included with the product or available on the Intermatic website for complete terms and conditions․