Indledning
The Intermatic WH21 Electric Water Heater Timer is designed to automatically control the operation of your electric water heater, allowing you to schedule hot water availability during periods of high demand and turn it off during low-demand times. This helps optimize energy consumption and reduce utility costs. This manual provides essential information for the safe installation, operation, and maintenance of your WH21 timer.
Vigtige sikkerhedsoplysninger
RISIKO FOR ELEKTRISK STØD:
- This device is a single-pole time control and should ikke be used as a power disconnect.
- Always turn off power at the main electrical panel before servicing this switch or the equipment it controls. Failure to do so can result in serious injury or death.
- Connect only to No. 10 AWG copper conductors or larger to the switch terminals. Ensure all wiring complies with local electrical codes.
- Installation should be performed by a qualified electrician or a knowledgeable individual with experience in electrical wiring.
Produkt overview
The Intermatic WH21 timer is a robust mechanical device designed for reliable performance. It features:
- Up to 12 ON/OFF settings per day for precise scheduling.
- A manual override button to temporarily turn the water heater ON or OFF outside of the programmed schedule.
- Durable construction suitable for residential electric hot water heater applications.

Billede 1: Front view of the Intermatic WH21 Electric Water Heater Timer. The gray box features the text "ELECTRIC WATER HEATER TIMER BY INTERMATIC" and a manual ON/OFF switch. This switch allows for temporary manual control of the water heater, overriding the programmed schedule.
Opsætning og installation
Proper installation is crucial for the safe and effective operation of your water heater timer. Refer to the internal wiring diagram and follow these general steps:
- Strømafbrydelse: Locate your main electrical panel and turn off the circuit breaker supplying power to your water heater. Verify that power is off using a voltage tester.
- Montering: Mount the WH21 timer securely to a wall near your water heater. Ensure it is in a location that allows for easy access and visibility.
- Ledningsføring:
- Open the timer enclosure to access the wiring terminals.
- Identify the incoming power lines (LINE) and the wires leading to the water heater (LOAD).
- Connect the incoming power lines to the designated LINE terminals on the timer.
- Connect the water heater load wires to the designated LOAD terminals on the timer.
- Connect the ground wire to the ground terminal within the timer enclosure.
- Ensure all connections are tight and secure. Use No. 10 AWG copper wire or larger as specified.
- Luk indhegning: Once wiring is complete, replace the insulator and securely close the timer enclosure.
- Gendan strøm: Return to your main electrical panel and turn the circuit breaker back on.

Billede 2: Indre view of the Intermatic WH21 Electric Water Heater Timer. This image displays the mechanical time dial with AM/PM markings and the wiring terminals labeled for LINE, LOAD, and GROUND connections. A caution label regarding electrical shock and wire gauge requirements is also visible.
Betjeningsvejledning
The WH21 timer is designed for straightforward operation:
- Indstilling af den aktuelle tid: Gently pull the time dial outwards and rotate it clockwise or counter-clockwise until the current time aligns with the indicator arrow. Push the dial back in to secure it.
- Programmering af tænd/sluk-cyklusser: The timer allows for up to 12 ON/OFF settings per day. To set a schedule:
- Locate the small ON (red) and OFF (black) trippers around the perimeter of the time dial.
- To set an ON time, slide an ON tripper to the desired time on the dial.
- To set an OFF time, slide an OFF tripper to the desired time on the dial.
- Ensure there is at least a 30-minute interval between ON and OFF settings.
- Manuel tilsidesættelse: The timer features an external manual lever (visible on the front cover, Image 1). This lever allows you to temporarily turn the water heater ON or OFF, overriding the programmed schedule. The timer will resume its preset program at the next scheduled ON or OFF operation.
Opretholdelse
The Intermatic WH21 timer is designed for minimal maintenance. However, periodic checks can ensure continued reliable operation:
- Visuel inspektion: Periodically inspect the timer for any signs of damage, loose connections, or corrosion.
- Rensning: Keep the exterior of the timer clean and free from dust and debris. Use a dry cloth for cleaning. Do not use liquid cleaners.
- Power Outages: I tilfælde af en magt outage, the mechanical clock will stop. You will need to reset the current time once power is restored to ensure the programmed schedule operates correctly.
Fejlfinding
If you encounter issues with your Intermatic WH21 timer, consider the following:
- Timeren fungerer ikke:
- Check if the circuit breaker for the water heater is ON.
- Ensure the current time is correctly set on the dial.
- Verify that the ON/OFF trippers are correctly positioned for the desired schedule.
- Confirm all wiring connections are secure and correct according to the diagram.
- Water Heater Not Turning ON/OFF as Scheduled:
- Check if the manual override lever is in the correct position (not overriding the schedule).
- Ensure the ON/OFF trippers are firmly in place and not loose.
- Verify the time dial is rotating. If not, the internal mechanism may require service.
For persistent issues, contact a qualified electrician or Intermatic customer support.
Specifikationer
| Feature | Specifikation |
|---|---|
| Mærke | Intermatic |
| Modelnummer | WH21 |
| Voltage Bedømmelse | 208-277 VAC |
| Nuværende vurdering | 25 Amps |
| Wattage | 6250 watt |
| Frekvens | 60 Hz |
| Antal operationer | Up to 12 ON/OFF per day |
| Indhegning | NEMA 1 |
| Switch Type | Single Pole/Single Throw (SPST) |
| Dimensioner | 5.25 cm B x 6.75 cm H |
| Varens vægt | 2 pund |
Garantioplysninger
The Intermatic WH21 Electric Water Heater Timer comes with a 1 års begrænset garanti from the date of purchase. This warranty covers defects in materials and workmanship under normal use. For specific terms and conditions, or to make a warranty claim, please refer to the official warranty documentation included with your product or contact Intermatic customer support.
Kundesupport
For further assistance, technical support, or inquiries regarding your Intermatic WH21 Electric Water Heater Timer, please visit the official Intermatic webwebstedet eller kontakt deres kundeserviceafdeling. Kontaktoplysninger kan typisk findes på produktemballagen eller i producentens webwebsted.





