Watts Tekmar WiFi Snow Melting Control 670 Скачать руководство пользователя страница 36

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Idle Operation

When the snow melting system starts from a cold temperature,

there may be a long time delay before the slab is warm enough

to melt snow. This time delay allows snow to accumulate on

the slab which is not acceptable in some commercial and

institutional applications. To decrease the start-up time, the slab

can be pre-heated to maintain a minimum temperature. This

is known as the Idle temperature. Idling requires large energy

consumption and is generally recommended for institutional

and/or commercial installations where safety concerns are

paramount. The display shows "System is Idling" when the

control is in idle operation.
When designing a snow melting system, an engineer may

specify the amount of allowed snow accumulation as the

Snow-Free Area Ratio. There are three different levels. A

Snow-Free Area Ratio of 1 is defined as a system that melts

all snow as it falls with no allowed accumulation. This requires

that the Idle temperature be set just below freezing. Examples

of these types of applications include:
•  Hospital emergency areas
•  Helicopter landing pads
•  Parking garage ramps
A Snow-Free Area Ratio of 0.5 is defined as a system with

partial snow accumulation on the slab but not in all areas.

These types of systems may also use Idling but usually set

at a temperature several degrees below freezing to reduce

energy consumption. Applications may include:
•  Steep residential driveways
•  Commercial sidewalks
•  Loading docks
A Snow-Free Area Ratio of 0 is defined as a system that

allows snow accumulation. These systems operate the snow

melting system from a cold start resulting in the lowest energy

consumption costs and the longest times to start melting snow.

In this case set the Idle to off. This is recommended for most

residential applications such as:
•  Flat residential driveways
•  Patios
•  Residential sidewalks
Some systems are designed for keeping a slab surface free of

ice rather than free of snow. The most common applications

include:
•  Car wash bays and aprons
•  Aircraft hanger aprons
•  Turf conditioning on golf course greens
These systems require the use of Idling at or near freezing

throughout the winter and may result in high energy consumption.

Storm Operation

The Storm operation combines the benefits of a fast response

time together with lower operating costs. Typically the storm

temperature is set below freezing to maximize energy savings.
In the event that snow falls and is detected by a Snow/Ice

Sensor or a Snow Sensor or the system is manually started, the

snow melt system heats the slab up to the melting temperature

and completes a melting cycle.
Should no snow fall during the storm time period, the control

exits Storm operation and returns to Off.
The Storm operation is set up by setting the Storm temperature

and the Storm Run Time in the Temperatures menu.

Auto Storm

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