International Pool Expert, Aquatic Designs, Watershape Consultants, Aquascape Consulting, International Aqua Designs, Swimming Pool Construction, Aquatic Facilities Plans, Pool Plans, Pool Designs, Structural Pool Engineering, Tile Pools, Cracked Glass Tile Expert, Paolo Benedetti, Aquatic Technology Pool and Spa, www.aquatictechnology.com, Indoor Pools, Rooftop Pools, Basement Pools, hydraulic moveable pool floors, pool construction defects expert.
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.
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.