6
Outlets Per Pump
Provide at least two hydraulically balanced main drains, with covers (see Page
5), for each swimming pool pump suction line. The centers of the main drains
(suction fittings) must be at least three feet apart.
The system must be built so that it cannot operate with the pump drawing
water from only
one main drain (that is, there must be at least two main drains
connected to the pump whenever it is running). (See Figure 2). However, if
two main drains run into a single suction line, the single suction line may be
equipped with a valve which will shutoff
both main drains from the pump
(see Figure 2).
More than one pump can be connected to a single suction line as long as the
requirements above are met.
Water Velocity
The maximum water velocity through any suction outlet must be 1.5 feet per
second unless the outlet complies with the latest ASME/SNSI Specification for
Suction Fittings For Use in Swimming Pools, Spas, Hot Tubs, and Whirlpool
Bathtub Applications. In any case, do not exceed the suction fittings maxi-
mum designed flow rate.
If 100% of the pump’s flow comes from the main drain system, the maximum
water velocity in the pump suction hydraulic system must be six feet per sec-
ond or less even if one main drain (suction fitting) is completely blocked. The
flow through the remaining main drain(s) must comply with the latest
ASME/ANSI Specification for
Suction Fittings For Use in Swimming Pools,
Spas, Hot Tubs, and Whirlpool Bathtub Applications.
At Least
3 Feet
Suction Outlet
(Main Drain)
Suction Outlet
(Main Drain)
IAPMO Certified
Anti-entrapment
Cover or Suction Fitting,
screw-fastened to
Main Drain Sump
IAPMO Certified
Anti-entrapment
Cover or Suction Fitting,
screw-fastened to
Main Drain Sump
Pump
Valves OK between
pump and Tee
No valves between
Tee and Main Drains
2762 0197
Figure 2 – Recommended pump suction layout.
