Six months past the compliance deadline for the Virginia Graeme Baker Pool and Spa Safety Act, pool professionals are still learning the nuances of the law. Simply screwing down a newly compliant drain cover without considering a pool’s hydraulics may not be making the pool any safer. Similarly,
incorrect installation of a safety vacuum release system can defeat the very purpose of the device.
And all too often, service techs lean on intuition and
last-minute phone calls when installing an SVRS.
“It’s kind of like a dad with a bike at Christmas
time — the last thing in the world he wants to do is to read
the instructions,” says George Pellington, East Coast sales
manager for Vac-Alert in Ft. Pierce, Fla.
The installation of SVRS devices is relatively simple. However,
techs should be aware of some common mistakes and work-arounds that
occur in the field. If the units are installed correctly, they
should provide a vital layer of protection rather than a tripping
Remember, most manufacturers provide installation support in the
form of written instructions, DVD tutorials and online diagrams.
This primer should always be secondary to a manufacturer’s
Location, location, location
For the uninitiated, an SVRS is a vacuum-sensing device that either
sends air to the pump and/or powers down the pump motor when it
senses a vacuum increase.
“The [unit] acts like a mechanical vacuum breaker, just
like you have a GFCI in your bathroom that protects the
outlet,” Pellington explains.
Generally there are two types of SVRS devices: electrical and
mechanical. The mechanical models send air to the pump so it will
cavitate, thus releasing the vacuum. The electrical models do this
as well, in addition to actually powering off the pump.
Choosing the SVRS is both a matter of preference and setup. Some
units are designed to operate at certain vacuum levels, while
others can be calibrated for greater range.
“The standard unit without the adjustability caters to
your shorter pipe runs and lower-range vacuums,” says Mike
Steffen, sales manager at Vac-less in Simi Valley, Calif.
Furthermore, certain units may be a better fit for certain
vacuum levels. The higher vacuum pools often have larger pumps and
more labyrinthine hydraulics. In some cases, the tech will be
better served to downsize the pump. While most units have an
adjustable vacuum reading, many SVRS manufacturers recommend a
level under 18 inches of mercury.
Installations vary by maker. To minimize the vacuum and ensure
accuracy, some manufacturers recommend installation on the main
drain line only, without picking up vacuum from the skimmer.
“We discourage people from putting the Vac-Alert on common
lines, because then it would be required that it be sensitive to
all circuits, and it’s not as good an install,”
Although proximity to fittings is not a major issue, keeping the
unit between 5 feet and 18 inches from the pump makes for the best
install, he says.
Still, other units attach directly onto the pump.
“All you have to do is remove the suction-side drain
plug,” Steffen notes. “We have a little extension elbow
that we provide as an optional installation piece, but basically
our unit is just hand-screwed into that plug.”
While mechanical units are physically plumbed into the
hydraulics, electrical units require installers to drill a small
hole in the suction-side plumbing, connecting a tube from the pipe
to the SVRS.
“We tell people to tap it at 10 o’clock or 2
o’clock, because if you do it straight at 12 o’clock,
if any air gets in there, it will go to the top of the pipe
first,” says Russ Burke, district sales manager for Hayward Pool
Products in Pomona, Calif.
Electrical units should also be properly grounded and bonded
according to local codes.
Finally, you will need to calibrate the system. Make sure the
filter is clean to ensure a standard vacuum level. For any pool
with a higher vacuum rate, manual units will have to be adjusted to
find the right setting.
“You turn the cap clockwise or counter-clockwise, which
will basically compress or expand the spring tension to allow the
piston to hit the air channels that are designed inside
there,” Steffen explains.
Consult the manufacturer to ensure your vacuum level is within a
Nuisance tripping on SVRS systems often is the result of incorrect
installation or poor maintenance. For units with an automatic
restart, these trips may simply be an annoyance. But for any SVRS
that requires a manual restart, nuisance trips on an untended pool
can add up to very green water.
Many units are sensitive to the small changes in vacuum, and a
swing of 3 inches in vacuum could trip the SVRS.
Check valves, for example, on the suction-side of the pump can
drastically change vacuum levels.
“You cannot have a check valve on the suction side of the
system — the fluttering of it could have it trip,”
These valves should be taken out prior to installation.
Be aware that installing a new drain cover will also change the
vacuum level. Unless the replacement cover has the exact same open
surface area as the original cover, the pool will be operating at a
different vacuum level. A large difference in open surface area
could cause the unit to trip.
Although less common, poor maintenance could also cause nuisance
tripping. An untended pool can build up its vacuum level with
“The pump and the skimmer basket, especially…when
the winds kick up, could cause a trip, but they would have to be
pretty packed,” Burke notes.
Occasionally, something random can block the outlets, such as a
towel on the main drain or a plastic bag in the skimmer, he adds.
However, these are unavoidable consequences of a public pool.
Be aware that changes on the pressure side of the pump can
affect the vacuum level as well.
“If the pump is pumping against a higher pressure and
therefore at a lower flow, the vacuum level actually goes
down,” Pellington explains.
Some units will trip with a drop in vacuum as well as an
increase. This means a dirty filter, return-side blockage or an
impacted pump impeller could cause problems. Techs should
investigate these areas when diagnosing a false trip.
The successful operation of an SVRS also depends on proper testing
and maintenance. When the installation is finished, the SVRS should
be tested several times to ensure it will work when the pool
experiences a vacuum drop. Techs can also use a pole-guided mat to
move over the main drain, although that’s best for single
Installing a ball valve just before the SVRS is also a popular
option for testing. Turning the valve on should set off an instant
change in vacuum and cause the unit to trip.
Choosing between the two may be a matter of preference.
“Some building officials like the mat test because they
feel it better simulates a real entrapment event,” Pellington
notes. “Others are quite happy with the valve
because…they can test it.”
Furthermore, if the SVRS is installed on a residential
application with a ball valve, the homeowner may even test it to
ensure it’s operating properly. Most manufacturers recommend
testing the unit on a monthly basis.
Maintaining the unit often is a matter of keeping a steady
vacuum level and addressing any tripping.
If a trip does occur, depending on the model, SVRS units will
either automatically reset after a given amount of time —
often programmable with the electric units — or stay shut off
until a service tech can manually reset it.
“Some people prefer that to make sure they’re able
to resolve any incidents and have time or ability to reactivate the
unit,” Steffen notes.
If the unit does require a manual reset, make sure a service
technician is available, particularly in a commercial pool
Also, make sure the line from the SVRS unit to the plumbing is
clear. If there’s any kind of blockage in the tubing or on
the vent screen, the unit will not be able to send air to the pump
to prevent a suction entrapment.
Keeping the SVRS from tripping when doing maintenance.
Get a step-by-step look at a spa drain cover retrofit.