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WarmlyYours Snow Melting & Slab Heating User Manual

Page 8

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5.4 INSTALLATION UNDER CONCRETE

1. Ensure that the concrete contractor has installed a solid base of 4” to 8” (102 mm

to 203mm) of crushed rock aggregate base and that it is tamped down and ready

for the concrete pour.

2 . It is extremely important that the concrete installer does NOT use any heavy

equipment, machinery, or vehicles over the exposed Heating Cable. During

concrete pours, it is recommended that care be taken to avoid stepping on the

transition portion of cable, where the hot section (green) meets the cold section

(black). This is the location of the factory splice. During this process of installing

the heating product and pouring concrete, it is the responsibility of the electrician

to use a 500 VDC megohmmeter and a multi-meter to keep checking on the

Heating Cables that are currently being worked on top of, to ensure they have not

been damaged, and will be ready for action once the concrete slab has cured.

3. For installations in stairs and ramps that will include hand rails, it is strongly

recommended that the concrete installer pre-sleeve for the posts to avoid any

and all drilling of the concrete. The Heating Cable must be routed around these

sleeves or posts to avoid any direct contact with them. Heating Cables or Mats

must not be allowed to pass thru expansion joint locations. It is recommended

that lines are spray painted on the finished concrete surface by the electrician to

mark off exactly where expansion joints may be located. It is the responsibility of

the electrician and the concrete installer to coordinate their efforts so they avoid

saw-cutting or drilling thru Heating Cables that are no longer visible beneath the

concrete. Following the proposed installation plan from WarmlyYours will help to

ensure this process goes smoothly.

4a. For Two-Pour Installations: The concrete installer pours the first 2” to 3” (51mm

to 76mm) of concrete. While this first pour is still wet, rebar or wire-mesh should

be placed on top of the first pour. The Snow Melting Mats / Cables should be

attached to the rebar / mesh with plastic zip ties, using 3” to 4” (76mm to 102mm)

spacing for free-form type cable. At this time, the electrician must route the cold

lead(s) thru rigid metal conduit(s) to get back to an accessible weatherproof

junction box(es). Care must be taken by the electrician so that none of the

heated section enters any conduit. If a slab-mounted snow sensor will be used,

this is the best time for placement. It should be located in an open area away

from trees or bushes so that snow will easily fall directly on it. Separate conduit

should be used to protect the low voltage sensor wire and must NOT be shared

with any high voltage cold lead from the Heating Cables / Mats. Once conduits

& sensor(s) are placed, the topping pour of concrete can be finished. Again, the

concrete installer(s) must take care not to walk on the hot-cold splice point, and

to avoid damaging the Heating Cables with shovels and rakes. Taping up the

shovel blades helps make them less sharp. Like with asphalt, it’s recommended

that Mats be placed so the mesh faces up, keeping the wire-side-down to help

protect it from the shovels.

4b. For Single-Pour Installations: The wire mesh or rebar is first placed by the

concrete installer or electrician. The electrician then must attach the Heating

Cable to the rebar / mesh with plastic zip ties using 3” to 4” (51mm to 76mm)

spacing for free-form type cable. Then the rebar / mesh must be propped

up with concrete rubble, wire chairs, or brick pavers to the appropriate depth

so that Heating Cable / Mat ends up 2” to 3” (51mm to 76mm) from finished

surface and no deeper. Once rebar / mesh / Heating Cable is all propped up, the

electrician must route the cold leads(s) thru rigid metal conduit(s) to get back to

an accessible weatherproof junction box (es). Care must be taken so that none

of heated section enters any conduit. If a slab-mounted snow sensor will be

used, this is the best time for placement. It should be located in an open area,

away from trees or bushes, so that snow will easily fall directly on it. Separate

conduit should be used to protect the low voltage sensor wire and must NOT be

shared with any high voltage cold lead from the Heating Cables / Mats. Once

conduits & sensor(s) are placed, the pour of the concrete can be finished in one

step. The concrete installer(s) must take care not to walk on the hot-cold splice

and to avoid damaging the Heating Cables with shovels and rakes. Mats should

be placed mesh facing up, keeping the wire-side-down, to help protect it from

the shovels and rakes.

5. The electrician needs to complete final testing of all the Heating Cables / Mats

with a multi-meter and a megohmmeter to verify and record that each Heating

Cable has survived the pour of concrete and is ready for action once the concrete

is cured. These values must be recorded on the warranty card on page 22.