User manual

Chapter 2: Installing your SEC-HD Phason
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One of the most common causes of power surges is lightning. When lightning strikes the ground, it
produces an enormously powerful electromagnetic field. This field affects nearby power lines, which
transmit a surge to any device connected to it, such as lights, computers, or environmental controls
like your SEC-HD. Lightning does not have to strike a power line to transmit a surge.
Surge suppression devices offer some protection from power surges. Because it is not possible to
internally protect this product completely from the effects of power surges and other transients,
Phason highly recommend that you install external surge suppression devices. For specific
recommendations, see your electrical contractor. If you do not take these precautions, you
acknowledge your willingness to accept the risk of loss or injury.
Reducing electrical noise using filters
Electrical noise is caused by high voltage transients created when inductive loads, such as power
contactors, are switched on or off. The strength of the transients can be over 1000 volts and can
vary with the type of equipment and wiring, as well as several other factors.
“Visible” symptoms of electrical noise include erratic control operation, cycling inlets,
communication problems, and more. However, the effects of electrical noise are not always visible.
Over time, electrical noise can cause electronic circuits, relay contacts, and power contactors to
deteriorate.
Installing filters helps extend the life of equipment
Filters help prevent electrical noise problems by absorbing the transient energy. Even if you do not
have visible symptoms of electrical noise, filters help keep controls operating reliably and can extend
the life of the controls and equipment connected to them.
Phason’s snubber filters (part number 127-0) are for use with solenoids, timer relays, DC motors,
furnaces, and other equipment connected to the control’s relays. You can also use the filters with
loads connected to power contactors.
Install a filter in parallel with the load, as shown in the following example.