Tuesday, October 22, 2013

Safe Skimmer Equalizer Lines

Skimmer equalizers should be required when skimmers are the sole source of suction for a pump.

We have proven that main drains are not required for proper circulation.  It is irresponsible to suggest the elimination of equalizer suction outlets as well, and thereby the protection for multi-thousand dollar pumps and proper water sanitization.

Low Flow Conditions

Low flow situations can occur from low water levels, weirs that become askew from kids playing with them, excessive waves, debris (goggles) and wear.  The baskets can become blocked due to latex bathing caps, inflatable toys, paper napkins, leaves or other unexpected debris.

When skimmers are the sole source of suction for a pump, the lack of equalizer suction outlets will deadhead the pump or cause a run dry condition, if the skimmers become clogged or inoperative.  The expense of repairing damage to pumps from "run dry" conditions, will become the burden of the designer or installer, because the damage is easily preventable through the use of equalizer suction outlets.


Most skimmers have flow ratings of only 75 gpm.  Skimmers should always be installed in a minimum of pairs, even more if the designed flow rate of the system demands it.   

Equalizers should be installed in a configuration that limits their line velocities to no more than 3 FPS and provides suction entrapment protection in compliance with VGBSA (some jurisdictions have a restriction of only 1.5 FPS).  Since anti-entrapment covers are derated when wall mounted, more than two equalizer inlets may be required to maintain a compliant flowrate.  Equalizers suction outlets should be installed with a minimum of three feet of separation and with the proper sump configuration.
Don't merely rely on Variable Speed Pumps

Variable speed pumps have an inherent design flaw.  When they shut down in a “self protection mode” due to loss of prime or low flow conditions, they do not provide an alert to their attached control systems or a remote control panel.   

Critical filtration and sanitization systems may become locked out for extended periods of time without any indications or warning signals.   In commercial pools or spas, this could quickly result in unsanitary and unsafe water conditions.  When system flow is critical to prevent facility damage (e.g. operation during freeze conditions), inoperative pumps are unacceptable as more severe damage to the facility may occur.

The Solution is Inexpensive
Properly installed with float valves and equalizer line check valves, equalizers will be dormant most of the time.  Only an equalizer check valve (pop-it check valve) in the skimmer can prevent suction on the equalizer line.  A float valve by itself will actually divert some suction to the equalizer lines.  

Therefore, float valves AND equalizer check valves should be utilized together, to prevent suction on the equalizer lines, except in critical skimmer low flow situations.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. 
Visit his website at: www.aquatictechnology.com. 
All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.

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To contact the author, Paolo Benedetti of Aquatic Technology pool and Spa, email him at: info@aquatictechnology.com or call 408-776-8220.
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