Snow Melt OmniMat 4" Spacing, 240V, 3′ x 20′, 60 sq. ft., 9.6A
Part Number: WHMA-240-0320-4
This support page provides publications, manuals, specifications, videos, support articles, and common support questions
This support page provides publications, manuals, specifications, videos, support articles, and common support questions
Common Support Questions (53)
Publications and Manuals (19)
Specifications (22)
Videos (12)
Articles (4)
Related Items (18)
Similar Items (29)
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Common Support Questions
That depends on a number of variables (like the temperature outside) but generally speaking these snow melting systems are designed to melt 1" - 3" of snow per hour. Anything above 3" per hour is typically considered blizzard conditions.
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Never cut the heating cable. A heating cable will not work if it has been cut. If the heating cable is too long, call WarmlyYours to consult with a technician who will guide you in utilizing the additional length of cable.
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The material costs are similar. However, electric systems are easier to install, with fewer components and significantly lower maintenance costs. Electric systems will run for a shorter period of time to give the same level of performance but with much higher energy efficiency (typically 95%-98% efficient). Controls and sensors required for the two types of systems are very similar. Electric systems do not usually require slab insulation and do not create the concerns typically associated with hydronic systems. These concerns include, but are not limited to, return temperatures, flue gas venting, waterway shrinkage and property damage caused by leaking pipes or tubes.
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When installing outdoor WarmlyYours snow melting cables for your driveway, patio, walkway, terrace, stairs, ramp, etc. - NEVER cross, overlap, or allow the heating cables to touch each other. Doing so will quickly cause a circuit failure due to excessive heat build up. Always follow the installation instructions and/or design layout plan to ensure the cable is installed with the correct spacing required for proper operation.
Solution:
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Yes. The manufacturer's splice that connects the heating element to the cold lead should be entirely embedded in a noncombustible material (like asphalt, concrete, or mortar) within the outdoor surface that is being heated.
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We suggest using cable to heat stairs as it is easier to route between the separate stairs.
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Our systems can handle low temperatures, but many controls come equipped with a Low-Temperature Lockout Feature. This feature prevents the system from running in very low temperatures. At very low temperatures it can become difficult for the system to effectively melt the snow. It is however possible to turn off this feature should you need the system to keep running during such low temperatures.
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Electric-resistance heating cables and systems have no polarity. This includes all current WarmlyYours heating elements.
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The electrician may shorten the cold lead wires during the installation. Any cold lead wire extensions/splices must be made in a junction box in accordance with the installation instructions, and must comply with all national and local electrical codes.
Never cut the heating cable.
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This National Electric Code (NEC) required protection for fixed outdoor deicing and snow-melting equipment may be accomplished by using circuit breakers equipped with ground-fault equipment protection (GFEP) of 30 mA. It is important to understand that this required equipment protection is not the same as a 5 mA GFCI used for personal protection.
Solution:
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Power requirements are measured in Amps and based on three factors: the watts per sq. ft. of the snow melting cable or mat, the area powered and the voltage used for the application. Our product is rated at 50 watts per sq. ft., so that is a constant factor. Most snowmelt projects are powered with 240V AC – not all, but most. The one factor that is always variable is the area to be heated/powered. That is based on your project. For a point of reference, let’s use the example above of a 350 sq. ft. concrete patio.
The formula is (50 W/sq. ft. x area of 350 sq. ft.) / V (240V) = Amps, so 17,500 / 240V = 72.9 Amps
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All of our automatic controllers have a Hold-on time feature after the initial warming up of the snow melt system. This feature ensures that all the snow is melted from the surface, and also that the system continues to operate and evaporate the surface water without it refreezing.
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Pavers can be removed and reinstalled for a retrofit application of our snow melt system. Tire tracks are not typically recommended for paver surfaces, so any retrofit application would most likely need to be full coverage. In this case, it should be treated like a brand new installation, just with existing pavers.
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This type of installation should not significantly affect the longevity of the driveway. Be sure to have a professional for your surface material type evaluate this during installation.
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To ensure optimal performance, snow melting heating elements should be installed so that they are consistently 2"-3" from the finished surface. For installations using pavers, the maximum thickness for pavers installed over heating elements is 2.5".
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Yes, you can retrofit a snow melting system into a preexisting driveway made of concrete or asphalt. You can do this by using an appropriate tool to cut properly spaced lines (or trenches for tire tracks heating) in the surface. Then you can place the the heating elements in the lines (or trenches) before sealing them with either hot asphaltic sealer for asphalt retrofits, or backer rod and expansion joint sealer (SikaFlex or similar) for concrete retrofits. Of course, you'll want to make sure this step is done in accordance with the filler manufacturer’s recommended procedures. Check out our snow melting retrofit guide for more information about this process.
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When the design requirement's amp draw exceeds the selected controller's capacity.
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If a cable is damaged during installation, recheck the system for continuity and confirm the integrity of the insulation with a megohmmeter, or "megger" tester, referring to the installation and testing instructions. If the cable fails any of these tests, take the following actions: clear a 3 foot square working area around the damaged section of cable, and record the cable part number from the UL tag and the location where you purchased the product. Call WarmlyYours with the above information. WarmlyYours will provide further assistance and supply a splice kit suitable for repairing the particular cable.
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To calculate the system's approximate operating costs, multiply the total kilowatts of the system by the cost per kilowatt in your area. Let's use the example of a 350 sq. ft. of concrete patio (residential application), with 240 VAC.
Total Watts: multiply area in sq. ft. x 50 Watts
350 x 50 = 17,500 Total Watts
Kilowatts: (the unit in we purchase electricity) take the Total Watts and divide by 1000
17,500 Total Watts / 1000 = 17.5 Kilowatts.
Kilowatt Rate: use the national average of .12 cents per Kilowatt-hours so how much do we pay for 17.5 kWatts?
17.5 kW x .10 = $1.75 for every full hour of operation.
Hours of Operation: We use a typical 6 hour snowfall for our example.
$1.75 x 6 hours = $10.50 for that snowfall.
All of this will vary due to "after-run time". "After run time" is where the system remains on extra hours after the snow has completed falling, to ensure complete pavement snow melting and drying.
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The most common spacing for snow melting systems is 3“ from wire to wire. However, we can design snow melting systems based on your local climate and weather expectations that might have different cable spacings to ensure the most efficient system possible. We also offer snow melting mats with 3" and 4" spacing.
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In an area free of obstruction and able to detect rain or snow, yet low enough so that it is easily accessible if service is needed. Atop a fence post or on an 'L' bracket on the side of a building are common.
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Yes, as long as the paver isn't resting on exposed cable. The cable has to be embedded according to the installation cross section drawing.
Cover to an uncompacted depth of 1.5” (38mm), leveled to grade. A compactor that's applicable to the thickness and application can be used to compact the sand. The paver installer(s) must take care not to walk on the hot-cold factory splice and to avoid damaging the Heating Cables with shovels or rakes. At no time shall the compactor directly contact the wire.
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Most outdoor systems will require an additional or sub panel to handle the amperage of the snowmelt system.
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Yes, but the cables will have a slightly reduced heat output. The wattage will be 13% lower, so that means instead of 50 Watts per Sq. Ft., the system will provide around 43.5 Watts per Sq. Ft. That is why WarmlyYours now stocks 208V cables."
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The layer of noncombustible material needed below snow melting heating elements must be at least 2" deep.
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Each heating cable comes with a factory installed cold lead wire that must be routed through the rigid metal 3/4" conduit to a outdoor rated junction box where a simple wire nut connection can be made for the electrical hook-up.
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Always confirm the power requirements with the electrician. Large snow melting systems usually require a new electrical panel or electrical service. Contact WarmlyYours for a quotation, indicating the actual power capacity available, and to obtain recommendations for reducing the power consumption. For example, opting for tire track coverage rather than installing the snow melting system over the entire driveway can dramatically reduce power requirements.
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Yes. Information on how to install under permeable pavers can be found in section 4.6 of the Installation Manual
. Excavate 18” and fill with #2 aggregate/stone.
. 4” of #57 stone
. 2” of #9 stone to serve as the paver setting bed.
. The heating cable is installed within the #9 stone layer.
To maximize the amount of heat transferred from the heating cable to the pavers, the stone separating the cable and pavers needs as much contact with both as possible. Crushed stone with fines transfers the most heat, but doesn’t drain, so it isn’t used in a permeable installation. Instead, smaller drainage stone (#9) is used because it has more contact with the cable and transfers more heat than larger stone.
Note: do not install the cable at the top so it’s touching the pavers. Potential movement by the pavers over time could wear through the protective coating of the cable and short out the entire installation.
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No, cold leads need to run protected in approved conduit into a junction box. In the junction box they may be attached to wires carrying voltage from the main circuit.
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No, additional wiring is supplied by the electrician.
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The electrician must route the cold lead(s) through rigid metal conduit(s) or other approved means, to get back to an accessible weatherproof junction box(s). Care must be taken by the electrician so that none of the heated section of Cable enters the conduit(s).
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Once you've decided what type of heating system (manual vs. automatic), you'll need to choose a control, which may or may not utilize a sensor. You may need a relay panel(s) depending on the size of the system, and a snow melt plaque which is required by the National Electric Code. Junction box(es) may be optional depending on the distance of heating cable from the indoor power location.
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Minimum is 1.5“ and Maximum is 2.5“
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No. Each snow melt mat comes with a 20‘ cold lead.
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Yes, WarmlyYours Snow Melting Heating System can be installed with quartzite stones. Start with 4” to 8” (102mm to 203mm) of crushed rock aggregate base. Rebar or wire mesh should be staked on top of this base and then heating cables or mats will be tied to this mesh with plastic zip ties. Heating system needs to be covered with 1” to 1.5” (51mm to 76mm) of finished mortar or sand. Stone Pavers will be installed on top but must NOT be any thicker than 2.5” (63.5mm). See cross-section in the documents section and in the manual.
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Yes, the leads are not direct burial rated. The leads must be protected in compliance with local electrical codes.
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Any outdoor rated plastic, watertight junction box will be acceptable.
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A properly designed and installed system will handle most snow melting demands. Some snow events may have a very rapid snow fall rate, and some may not. No 2 events are ever exactly the same. Our system typically can melt 1“-2“ of snow per hour, on average. However, it is important to understand that a system may not melt snow at very cold temperatures. This is simply because the system cannot generate enough BTUs to overcome the heat loss generated by very low temperatures.
In order to estimate cost of operation, the Warmly Yours Electric Snow Melting Operating Cost Calculator is a useful tool that can help illustrate what it would cost to operate the system.
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The snowmelt cables/mats can withstand direct contact with asphalt temperatures of up to 464°F (240°C).
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120, 208, 240, 277 voltages.
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No, chicken wire is too flimsy. A rigid framework without sharp edges, such as rebar or wire mesh, needs to be used to ensure that the embedded heating system is the proper distance from the finished surface. We recommend that the heating system is secured to the rigid framework with plastic zip-ties.
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No, a sensor is not required with the snow melt system. However, certain automatic controllers require a temperature/moisture sensor to sense atmospheric conditions and may also require an in-slab, high temperature limit sensor to be installed (notably, asphalt installations).
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We recommend that the layer of landscaping rock be no deeper than 2.5". If the snow melting heating elements are embedded any deeper than that, then the system may not yield satisfactory results.
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When heating stairs, we recommend minimizing or eliminating overhangs/lips on stair surfaces. It is very difficult for the heat to reach these protrusions, as heat only transfers, at most, 2" to 3” laterally from the cable. This is why we recommend placing a run of the heating cable right at the front edge of the stair, which will help keep this area clear of snow or frost as much as possible. The riser of the stair is not heated--only one run of cable goes down the riser to reach from an upper stair to a lower stair.
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It depends on how the system is intended to operate. If the expectation is manual operation (ex. WiFi or Timer Control), then no sensors are required. If the expectation is automatic operation, then the system will require at least one snow sensor.
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The US National Electrical Code prohibits electric heating cables in pool decks. Please check with your local Authority Having Jurisdiction to see if your local code allows this, as local code overrides the national code.
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Yes. The NEC requires 2“ minimum of non-combustible material below, and 1.5“ minimum of non-combustible material above the heating cable.
The drawback is whether or not the pervious concrete will fail under load, thereby damaging the heating cable and voiding warranty. The cable should be attached to rebar in this case to insure the strongest support.
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Test the Snow Melt cable or mat using a digital ohm meter as shown here. Also test the snow melt cable or mat using a Mega Ohm meter as shown here. And this video shows how to do the Ohm test.
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A 2 pole single-phase 240V circuit works by continuously monitoring the current flowing through both hot wires of the circuit. If it detects even a slight imbalance between the current on each hot wire (indicating a ground fault), it will quickly trip, cutting off power to the circuit. Essentially, it compares each leg of the 240V circuit and trips if they are not precisely equal.
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Ground fault equipment protection (GFEP) is intended to provide protection for equipment against damaging line-to-ground currents by disconnecting all ungrounded conductors of the faulted circuit.
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The best time to install an asphalt driveway is generally from spring to fall. The contractor has more time to work with asphalt at warmer temperatures of 50°F / 10°C and above. The warmer the better. The contractor has less time to work with asphalt at colder temperatures and lesser depths. For example, at 40°F / 4°C, a contractor has only 25 minutes to work with a 2" thick asphalt installation.
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This feature prevents the snow melting system from running, by default, in temperatures below 17°F (–8.33°C), or as set by the user. At temperatures this low, it becomes difficult for the system to effectively melt the snow. It is, however, possible to turn off this feature should the system be required to keep running during these low temperatures.
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The correct bedding material should be washed concrete sand meeting ASTM C33 gradation.
Please review this WarmlyYours Snow-Melting cross-section for proper installation.
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Publications and Manuals
Installation
Snow Melting Installation Manual (English)Snow Melting & Slab Heating Application Cross Sections (English)
Manual de Instalación para Sistemas de Derretimiento de Nieve (Spanish)
Snow Melting & Slab Heating Application Cross Sections (Spanish)
Snow Melting & Slab Heating Application Cross Sections (French)
Snow Melting Installation Manual (French)
Technical Support
Floor Fault Location Thermal Camera Troubleshooting Kit Instruction (English)Snow Melting Mega Ohm Reading Instructions (English)
Floor Fault Location Thermal Camera Troubleshooting Kit Instruction (Spanish)
Floor Fault Location Thermal Camera Troubleshooting Kit Instruction (French)
Instrucciones de lectura del Mega Ohm de fusión de la nieve (Spanish)
Snow Melt and Slab Heat Endcap Repair Instructions (English)
Snow Melt and Slab Heat Repair Kit Instructions (English)
Sell Sheets
Outdoor Display Program Sell Sheet for Canada (English)Snow Melt Controller Comparison Sheet (French)
Snow Melting Mat Sell Sheet (English)
Specifications
Electrical
| Amps | 9.58 A |
| Ohms | 25.04 Ω |
| Voltage | 240 V |
| Watts | 2300 W |
| Watts Per Sq. Ft. | 38.33 |
Warranty / Certifications
| Approvals | cCSAus Listed |
| Warranty | 10 years |
Performance
| BTU Per Hour | 7848 Btu |
| Heated Coverage | 65 ft² |
Product Dimensions
| Cold Lead Length | 20′ |
| Coverage | 60 ft² |
| Heating Element Spacing | 4″ |
| Heating Element Thickness | 5/16″ |
| Length | 20′ |
| Size | 3′ x 20′ |
| Size and Power | 3x20 ft - 38 W/sq.ft. |
| Width | 3′ |
Appearance
| Color | Green |
Logistics
| Country of Origin (COO) | India |
Identifiers
| SKU | WHMA-240-0320-4 |
| UPC (GTIN-12) | 881308074340 |
Installation
| Surface Types | Asphalt, concrete or in mortar under pavers |
Videos
Product Line Videos
Tech Tips: How To Test Snow Melting Mats and Slab Heating Cable
Full Coverage Snow Melting System Installation in an Asphalt Driveway
Time-lapse of a Tire Tracks System Operating During a Winter Storm
Snow Melting Install- From Start to Finish
Snow Melt Timelapse Comparison
Snow Melt installation under asphalt driveway
Introduction to WarmlyYours Snow Melting Systems
Snow Melting & Deicing Cable System Installation In Concrete
How to Cut the Price of Snow Melting Systems in Half
Why and How to Install a WarmlyYours Snow Melting System
Reasons to Install a Snow Melting System
Articles
IPX Ratings
Should Stone Dust Be Used in Paver Snow Melting Jobs? Paver Installation Recommendations
Snow Melting System Is Not Melting Snow
What is the difference between mortar and cement?
Should Stone Dust Be Used in Paver Snow Melting Jobs? Paver Installation Recommendations
Snow Melting System Is Not Melting Snow
What is the difference between mortar and cement?
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