Variable-speed pumps have come a long way, just ask Ben Honadel.
Five years ago, when a homeowner called his company to enquire
about the product, a representative would explain its benefits. The
customer would either make the purchase then, or say they wanted to
discuss it with their service technician.
“That’s when we’d run into trouble,”
explains Honadel, owner of Pools by Ben in Santa Clarita, Calif.
“Either we wouldn’t hear from the homeowner again, or
they’d call and say, ‘The pool man told me
they’re no good, they’re too expensive, and they
don’t save money. Why are you trying to sell snake
Flash forward to today, and the pumps have evolved, along with
attitudes about them. Models are entering the market that
don’t require a specific manufacturer’s controller, or
any controller at all, making it easier to fit them into existing
circulation systems. And professionals are finding that not only do
variable-speed pumps save energy, but they can result in cleaner,
quieter pools, and help builders create custom features.
Here, installers who’ve come in from the ground floor discuss
how to maximize the benefits of today’s variable-speed pumps.
The big picture
Today, when working with a new pool or extensive renovation that
involves replumbing, builders can gain as much as 70 percent energy
savings with a VSP.
But many builders and service techs don’t install or program
the products to deliver the maximum benefits.
On existing pools, there is less flexibility. Builders must set a
maximum pump speed to correlate with the plumbing capacity.
But for new pools and replumbs, the system should be designed with
the least head pressure so the water can run on low speeds. This
also can accommodate the pump at its full 3,450 rmps, should it
ever be ramped up to the maximum.
Benefits of VSPs also include programming. The key is to run the
pump on the lowest speeds possible for long periods of time. And if
local utilities charge higher rates to run at peak hours, the pumps
also should be set up to operate at their highest speeds during
off-hours, when possible.
The most energy savings and cleanest water result from running the pumps all day.
This is especially appealing when installing corona discharge ozone
systems. Since this technology doesn’t leave a residual,
they’re best to run 24 hours a day so the water is
continually sanitized. But even when using chlorine, it helps to
move the water all day because the chemicals are constantly being
mixed. “So you don’t have issues where, when the pump
shuts off, everything sits stagnant and the pH drops, and in the
deep end the pH changes,” Honadel says.
The bulk of the day, the water should run on a very low speed. This
mixes the water, but also is extremely economical. “If
we’re running at 600 rpm at 24 hours a day, our kilowatt
costs would be $8 per month,” says Barry Justus, president of
Poolscape Inc. in Burlington, Ontario, Canada.
Still, the water must run faster than that for a while in order for proper skimming, and for chemical feeders and automatic cleaners to do their job. So program the unit to run at somewhat higher rates — for Justice, that means approximately 2,500 rpms — for as many hours as necessary to meet turnover requirements.
“The most common program we do is 22 hours slow and two hours at a skim speed,” Honadel says. “Skim speed is the time where the pool behaves like it did before [variable-speed pumps
were used]. It’s fast enough to skim the pool, to run an automatic pool cleaner, to heat the pool if you want the heater to turn on, and for a spa spillway or waterfeature to spill over.”
Ideally, set up the pump to do this at night, particularly in areas where it costs more to run at peak hours. If the system is plumbed correctly, the pump shouldn’t make enough noise to disturb homeowners while they’re sleeping, these professionals say.
Consult with the customer about when they want the pool and its features to run. “People have very specific needs and wants,” says Marc Del Chiaro, service department manager for Geremia Pools, a Pool & Spa News Top Builder in Sacramento, Calif. “Some have it come on four times a day for two hours on low speed, then they want their cleaner running in the middle of the night. Some like to sit outside in the morning, so they want the spillover action from the spa into the pool during
that time. Some people want to be out there and watch their cleaner as it’s working.”
Variable-speed pumps may be programmed to offer custom operation.
For instance, they can be set up so that vanishing edges and
perimeter-overflow pools run as efficiently as possible while still
sending enough water over the rim. “The tolerances are very
tight, and our goal is to keep the rpms down as low as possible
— just enough to wet the edge in order to save energy,”
He, for one, programs the pump so that when the vanishing-edge
system turns on, it runs at a higher rate for a few minutes —
just long enough to raise the water level, break the meniscus and
begin to spill. Then the rate goes down, so there’s just
enough water to wet the edge.
“Typically we’ll start the pump at around 2,600 to
2,800 rpm, then the edge will generally run at 1,000 to 1,400
rpm,” Justus says. “I have less water going down the
edge, the pump is a lot quieter, and there are substantial energy
He also uses the technology to simplify the plumbing of wet walls.
Because these waterfeatures usually don’t require the flow
generated by even the smallest single-speed pump, builders in the
past would restrict flow with valves or divert extra water with a
blow-off line. “Now, with the variable-drive, all you do is
gate back the rpms on the pump and get the exact flow,”
VSPs also can be used to operate larger rock waterfeatures on
different modes, from low to voluminous flows.
Justus further uses the pumps to offer customized spa jet options.
One of his clients was recovering from a shoulder injury and wanted
a variety of jet flows to help. Justice tried a 3-horsepower pump.
“But that was too strong — it was hurting his
shoulder,” Justus says. “We switched to a variable
drive. We programmed it with three different settings, and
he’ll choose one depending on how his shoulder feels that
day.” Builders can do the same for those who prefer different
Justus even uses the pumps to help minimize the effects of the
freezing Canadian winters. Rather than close pools, he can run them
at about 600 rpm to keep the water moving. “The relatively
warm water from the bottom of the pool gets sent up to the surface
and the water doesn’t freeze up nearly as much so there
won’t be a build-up,” Justus says. It costs hardly
anything to run, he adds, and especially helps minimize damage to
all-tile pools and waterfeatures.
When adding a variable-speed pump to an existing pool, installers
have to work with the plumbing that’s there. (Click here for a plumbing schematic on a raised
spa project using variable-speed pumps.)
But on new vessels, builders can truly get the most out these
products. The trick is to generate the necessary flow while running
at the lowest speeds. This requires large plumbing.
“You shouldn’t plumb a pool with a variable-speed pump
the same way you plumb with an oversized 2-hp induction
motor,” says Steve Toth, owner of Acclaim Pools in The
Experts have long recommended a balanced loop for plumbing spa jets
and pool inlets, but with variable-speed pumps, this kind of
schematic is crucial.
No more compensating for differential pressure by placing smaller
inlets close to the pump and using larger ones farther away. That
may work with a 2-hp pump, where there’s enough energy to
overcome head pressure in the system and send enough water to each
inlet, Toth says. “But if you’re trying to circulate a
pool with ½ hp or ¾ hp, and instead of having 13 feet of
velocity per second you only have about 2, you don’t have any
wasted head pressure.”
If you’re running a pump at the equivalent of ½- or
¾-hp, the plumbing should be larger and configured in a
hydraulically balanced loop. Otherwise, most of the water will move
through the returns closest to the pump, with little to nothing
coming out of the remaining inlets. “So you’ll wind up
with a dirty pool,” Toth says.
The rules for minimizing turbulence become even more important on
these installations. For instance, installers who have continued to
use hard 90-degree elbows should finally convert over to sweep 90s,
or use two 45s instead.
Without the right plumbing, not only are energy savings lost, but
the unit’s quiet operation is compromised as well. To
illustrate, Toth tells of the next-door neighbor to one of his
“My client’s pool has a 1-hp pump on it, and even
though it’s an induction motor, I can’t hear it.
Instead, all I hear is the variable-speed motor over the fence,
blaring away at 3,450 rpms, because the pool was never plumbed
Other adjustments must be made to compensate for the loss in
pressure: “You have to create head pressure in order to force
water up into a raised spa or waterfeature,” Toth explains.
He accomplishes this by placing a two-way valve on the pool return
side so he can adjust the flow into the spa.
“We’ll choke it down a little bit, create a little head
pressure that heads out toward the pool to force more up into the
raised spa,” he says.