Frequently Asked Questions

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Grässlin ICUBE™ Module FAQs | Surge FAQs | LED FAQs


The product I purchased is missing parts or came with broken parts. What should I do?

Please visit our Warranty Claims site for missing or damaged parts. 

I need to replace a broken part on my product. What should I do?

Please visit to purchase replacement parts.


Can I install the IG1200RC3, IG1240RC3 or IG3240RC3 at the main breaker?

 This device needs to be installed downsteam of a 15 or 20 ampere circuit breaker.


What is the Grässlin ICUBE™ Module?

Grässlin by Intermatic has developed a new adaptive defrost module for refrigerated walk-in freezers and coolers. It is an easy, versatile, innovative and affordable way to reduce defrost cycles by 40% or more per day! The module can be field or factory installed with our existing DTAV40 or DTSX (OEM Only) defrost timers. This controller provides major energy savings where walk-in freezers and display cases are used, such as in full service, casual and fast food restaurants; hospitals and health care facilities; convenience stores and supermarkets.

Why would our customers want to use the ICUBE™?

It will save customers money by reducing energy usage associated with defrosting walk-in coolers and freezer evaporator coils. Food Service businesses as described above are always looking for cost-effective solutions which can generate energy savings and ultimately save them money with a short return on investment. Some owners are using these types of intelligent evaporator efficiency controllers but with an extremely high cost and overly complicated control. These types of controls can also be very difficult to program and install which takes time away from the contractors, and we all know time means money. With the ICUBE™, you simply install the module right underneath the existing DTAV40 timer and run the sensing wire from the ICUBE™ inputs to the evaporator coils. There is no need to change any other wiring in the system!

What does Adaptive Defrost or Demand Defrost mean?

Both terminologies ultimately mean, a defrost control system which reduces defrost frequency by initiating defrosts or adjusting the number of defrosts per day in response to operating conditions (e.g., measurements that represent evaporator coil frost load, moisture levels in the refrigerated space, etc.) rather than initiating defrosts strictly based on compressor run time or clock time.

Why is the time scheduling still important in relation to defrosting evaporator coils?

Having a timer included within a defrost controller is essential since there are times when a defrost cycle should be delayed, such as a typical product loading period into the controlled cabinet area. When it comes to time initiated defrost controls versus temperature initiated (“Adaptive” or “Demand”), both have their own advantages and disadvantages based on conditional circumstances. Referencing an “Adaptive”/”Demand” temperature initiate only approach; during a high usage heat load condition, a frost load condition can occur at a more rapid rate due to the exterior ambient air infiltrating the box and making contact with the evaporator coil. A temperature initiate only approach could in-effect initiate additional defrost occurrences versus a typical time initiated control. By introducing a time/temperature hybrid type methodology as the ICUBE™ provides, maintaining the time scheduling aspect the control would in effect temporarily delay a defrost to initiate at an optimal low usage time. During this type of circumstance, a temperature initiate only approach would also in effect create longer compressor run times to pull the box down to the set temperature because it is defrosting during a high capacity period.

Should I have concerns about frost accumulation factors between overridden successive timed defrosts?

Although system capacity loss may occur if a frost load condition accumulates after an overridden defrost event, it would be minimal (10% or less) during a typical 6-hour interval between programmed times. If there is cause for concern and no need to delay a scheduled defrost event during a high usage condition, this type of risk can be averted by simply adding more time initiate schedules to the clock. The ICUBE™ module will override the defrosts anyway if the evaporator coil condition does not require defrosting.

Do you offer a defrost timer with the ICUBE™ already assembled into it?

Yes, the part number available will be DDT40. It easily retrofits into existing mechanical defrost timer applications.

Does the Grässlin DTAV40 Timer or DDT40 Defrost Control wire the same when used with the ICUBE™?

Yes! Other than running sensor wire from the ICUBE™ to the system evaporator coil/s, there is absolutely no change to wiring at the existing terminal locations or at the load or contactor points.

What does the ICUBE™ work with?

For retrofit or new installations, the ICUBE™ simply integrates into an existing or new Grässlin DTAV40 timer. For your convenience we also offer a complete defrost timer control (part #DDT40) which is essentially the ICUBE™ + DTAV40 already assembled together.

What are the part numbers for the different ICUBE™ variations?

  • ICUBE™ for DTAV40 = DDFM
  • ICUBE™ + DTAV40 assembled together = DDT40
  • ICUBE™ for DTSX (OEM only) = DDSX
  • Additional separate sensor accessory = 178--00002 (1 sensor, 1 input, tube clip and wire nuts)

Does the ICUBE™ come with a sensor included?

Yes, 1 sensor per package.

Does the complete DDT40 come with a sensor included?

Yes, 1 sensor per package.

What is included with the sensor?

1 sensor, 1 input, 3⁄8" evaporator tube clip and wire nuts.

What is the sensor lead length provided with the ICUBE™?

The probe length is 8'-10' and the input lead length is 5'-6'.

Is there sensor wire range limitations from remote condensing unit to the evaporator?

The ICUBE™ is very accommodating and offers an expandability range up to 400 feet (field expandable).

What type of wire can be used to expand the sensor from a remote condensing unit down to the evaporator coils?

Typical field used #18 AWG shielded or unshielded wire.

Can I use any type of sensor with the ICUBE™?

No. The 10K NTC thermistor required is the sensor which is included with the Grässlin ICUBE™. If additional sensors are required to accommodate multiple evaporator coils or service truck purposes please order the required sensor (178—00002) from your local distributor.

What makes the ICUBE™ sensor unique?

For ease of installation, we are providing a unique non-isolated evaporator coil sensor provided by Grässlin only and will be available at your local distributors. This is done to allow the refrigeration contractor to run the sensing wire through existing conduit/raceways in remote rooftop locations to the box cooler/freezer applications. We also want to ensure optimal performance and no possible conflict with sensors from different vendors.

Where is the recommended evaporator probe placement?

Typical bulb sensing placement on an evaporator tube is always at or within proximity to the 2 or 10 o’clock position. You can connect the probe to the coil using the provided 3⁄8" tube clip. You can also insert the probe between the evaporator cooling fins ensuring the probe is making good contact with the evaporator circuit tube. The evaporator location should be approximately 1" to 2" from either end and at the bottom quarter of the evaporator coil, or where frost typically accumulates the fastest. If there is uncertainty where frost accumulates the fastest, put the system into a manual defrost and monitor for the last area of the evaporator where frost is present prior to a completely frost free coil.

What about systems with more than 1 evaporator?

The ICUBE™ has 4 sensor inputs which can accommodate up to 4 evaporator coils. Typically, in a 4 evaporator system, a DTAV40 will activate a contactor which energizes the multiple defrost loads simultaneously. Once the ICUBE™ module senses a decrease in capacity in one or all of the coils, the ICUBE™ efficiency mode then shuts off and the timer will then initiate a defrost at the next scheduled interval.

Can I use more than one sensor per evaporator coil?

Yes! For larger evaporator installations multiple sensors can accommodate 1 coil in locations as described in the “evaporator probe placement” section.

How do I know when the ICUBE™ module is in efficiency mode and bypassing unneeded defrosts?

There is a blue LED indicator located at the top left corner of the ICUBE™ module. When the blue LED is on, this indicates the control is in bypass mode saving energy and your customer money!

What happens if the sensor fails?

In the event of a sensor failure, the control would then function as a typical standalone time initiated, temperature, pressure, or time terminated DTAV40. For quick and easy troubleshooting purposes, the LED indicator would then flash a code to indicate that sensor maintenance is required.

It is common for a service technician to “force” a defrost event to check out system operation, which is currently done by rotating the clock to pick up the next timed event. How is this achieved when using the defrost timer with an ICUBE™?

This is achieved very easily! Just spin the dial through two consecutive programmed defrost events within 60 seconds. This will manually force a defrost.


Why do some lighting controls fail to work over the lifespan of LED lighting applications?

Failure of a lighting control can be caused by the initial in-rush current required in order to light an LED. For example, when an LED light is turned on, an in-rush current is produced in order to light the bulb. That momentary millisecond of current spike creates stress on the contacts in the control and may shorten its lifespan.

What determines the level of in-rush current in an LED?

In every LED light, there is a driver—much like an electronic ballast—that determines the amount of start-up current required to illuminate the LED light.

Why does this pose a problem for the control?

LED drivers can vary widely from fixture to fixture, and not all drivers behave the same way. So, even though the LED light draws, for example, only 10W of power, the LED driver that produces the initial in-rush current can create a current spike of 10, 20, maybe 40 times that electrical load. The control needs to be able to withstand or work around that spike, and sustain that through the expected life of the LED.

What does LED compatible really mean?

When we say “LED compatible”, it means that Intermatic controls will not only work with your LED applications, but can sustain reliable control of them through the expected life of the LED lights.

What are the things I should consider when choosing a control for my LED lighting application?

It’s a natural inclination to think one must do elaborate calculations to figure out the best, most suitable control for a lighting application. However, Intermatic is able to provide access to simple and direct information about the suitability of your prospective lighting control solution. We can quickly and easily help you choose the right control.

How can you be sure that a particular control will work with my LED lighting application?

Each control is tested with thousands of on/off cycles to simulate actual in-use performance in the field.  This testing results in data that allows for the best pairing of choosing an effective control from Intermatic.

Why should I choose an Intermatic control?

Intermatic has truly taken the lead in this issue. Going beyond basic UL standards, Intermatic has developed a leading-edge testing capability in a UL recognized laboratory. Using NEMA 410-standardized testing methodologies, and thoroughly researched and repeatable test case scenarios, Intermatic products stand the test, not only to be LED compatible, but LED sustainable throughout the life of the lighting application.

Aren’t there industry standards for this?

Intermatic is focused on developing and implementing a rigid, robust testing approach in our UL-recognized laboratory to provide clarity to our customers.  Since there is no single industry standard for testing controls used for LED lighting, Intermatic took the best information from NEMA 410, UL and CSA standards, and combined them into a testing scenario for our products that could show true performance with LED Drivers.  This is particularly relevant for our controls that were originally designed for CFL and Fluorescent lamps to give assurance that they are robust enough to manage the in rush currents over the life of an LED driver.

What is NEMA 410?

NEMA has developed a standard that characterizes the electronic current inrush phenomena and proposes a testing methodology to ensure lighting control and lighting load compatibility. This standard is called NEMA 410—Performance Testing for Lighting Controls and Switching Devices with Electronic Drivers and Discharge Ballasts, which speaks to LED lighting.

How has Intermatic designed controls specifically to be compatible with LED?

Intermatic has implemented a number of proven solutions for addressing LED compatibility of its lighting control products. Our recent white paper, “Understanding Electronic Ballasts and LED Drivers and Their Impact on Photo Controls” (link), outlines four specific examples of the solutions we employ. One such solution, the “Zero-Cross” technique, is just one example of how Intermatic applies the most appropriate technique where it makes the most

Surge Suppression

Aren’t most surges caused by lightning strikes?

Most of us associate power surges with lighting strikes, but in fact, they are the least common cause of surges. 60 – 80% of surges happen within a house and are caused by events such as your air conditioner cycling on/off or turning on your vacuum cleaner.

Don’t surge protectors last forever? Why do I have to replace the module in the Surge Protective Device?

No, surge protective devices don’t last forever. When they’re doing their job, they absorb power surges and eventually become compromised. Like fuses that burn out or ink cartridges that run out of ink, eventually the surge protective device needs to be changed. Intermatic’s built-in LED lights make it easy to see when you’re protected and when it’s time to change a module.

How does “whole home protection” work?

The Surge Protective Device is hard wire directly to the incoming power source, protecting everything in your home that derives power from your electrical panel such as lighting, appliances, TVs, garage doors, printers, and so much more!

Should I still use plug-in surge strips for my computer or TV?

Another layer of surge protection never hurts. But, be aware that surge strips degrade over time and you can’t look and tell if it’s still providing surge protection.

What if I’m not comfortable changing the module that close to the fuse box?

You can still call your electrician. Now, it will be a simple, short service call, substantially reducing your time and costs.

Does the $25,000 warranty cover lighting strikes?

There are no surge protective devices on the market that can protect against a direct lightning hit. However, Intermatic’s comprehensive connected equipment coverage includes items that few if any manufacturers cover, such as microwave ovens, stereo equipment, and computers.

How do I file a claim under the Connected Equipment Warranty?

Call toll free 1(800) 270-7227 to leave a detailed voice message for surge claims only.

What do the red and green lights mean on my surge suppressor?

For most hardwired or panelmount models green lights indicate that power is present and the unit is ...


Why does the IG1240RC, EG240RC, IG1300-2T-1C and IG1300-4T-2C whole house surge suppressors have to be wired to a 15 or 20 Amp circuit breaker?

In order to replace the units should they fail, you need to have a disconnecting means.

New Product Highlights


The Intermatic® line of occupancy sensors are engineered and tested for long-lasting performance. In-Wall and Ceiling Mount sensors in both PIR (infrared) and dual (PIR/ultrasonic) technologies can monitor virtually any area within a building, providing solutions for any retrofit or new construction project. They utilize zero-crossing technology to suppress inrush current impact, supplying reliable ON/OFF sensing no matter the lighting technology.


The Intermatic® ICUBE™ Adaptive Defrost Module cuts defrost cycles--and utility bills--for the food service industry. Designed by Grässlin by Intermatic for commercial walk-in coolers and freezers, the smart-sensing technology behind the ICUBE™ continuously monitors evaporator coil temperatures and only allows defrosting when necessary at the next programmed timer interval.

Surge Protective Device Group Shot

The Intermatic® Surge Protective Device with Consumable Modules covers 100% of a home’s big investment equipment, from appliances and computers, to HVAC equipment and TVs. The Surge Protective Device uses replaceable Consumable Modules that allows homeowners to easily and safely replace a module when the built-in LED light indicates it has been compromised.