Backflow Prevention
Some states and municipalities
require that you protect the potable water supply from any possible cross-contamination, whether it's likely to happen or not. These are connections that could cause potable water
to be contacted by non-potable water, like sump water. All standard models
of Basepump are designed to prevent that from happening. However some states and municipalities require
a separate "approved" device
be installed to protect the water supply. In these cases, the solution has
been to install either a dual check valve (which may or may not be
"approved", depending on where you live), or a very expensive Reduced Pressure Zone (RPZ) device to
accomplish this. However, an RPZ will restrict water flow and in many cases prevent
a water powered system from operating. They are also expensive and require
an annual inspection by a certified technician
with special equipment made for this purpose. This inspection also has to
be reported (with a form) to the plumbing authority in your state or
municipality. This means paperwork, headaches, money, etc. Base Products
has developed an alternative to all this. Most municipalities
recognize Atmospheric Vacuum Breaker (AVB) devices. Most other water
powered backup sump
pumps cannot use them, but Basepump can. Because of its location on the
ceiling, it has the necessary height to prevent water from backing into
the potable water supply. It simply cannot happen if installed
properly.
Once installed, inspected, and approved there should be no further
question about it's safety. This makes it possible to meet the codes and
also keep the costs down.
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Water Powered Back-up Sump Pump w/ Atmospheric Vacuum
Breaker
Basepump Models RB750-AVB
HB1000-AVB CB1500-AVB
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| "B" All water discharges here to the exterior
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"C" Potable water enters here
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"A" Sump water
enters
here
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Understanding
the Water Powered Ejector principle:
Water
powered pumps use a siphon ejector system that creates a vacuum source
using potable city water pressure as it motive force. Follow along with
the photo above. The Ejector is
comprised of a "tee" configuration with three connection ports. A suction
port designated "A" is in contact with ground water in the sump. A discharge
port designated "B" is located outside the building and is an open drain. The third port
"C" is connected to
the potable water supply.
A diaphragm control valve is held in the closed position until
activated by a float in the sump. When the Ejector is not operating the control valve is held in
the closed position, the suction pipe "A" is empty, and discharge pipe "B", being self-draining to the exterior, is also empty.
To place an order NOW for this pump with the -AVB Add-on, click
this link to our ordering page.
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Back
Siphon Condition:
In the event of a
back siphon condition, ground water cannot cross contaminate the potable
water supply. The inherent design of the Basepump along with an approved
Atmospheric Vacuum Breaker (AVB) that is factory installed supports this
claim.
Industry
Standards:
Atmospheric
Vacuum Breakers (AVB)
Cross-connection is not subject to backpressure or continuous pressure.
Install AVB at least 6" above the highest point of discharge. Protection
is afforded against back siphon only. See a drawing of a correct installation below.
Notice that the discharge line slopes down and away from the Basepump.
This is critical to the design. If it cannot be installed this way for
any reason, it will not work properly and will not protect the potable
water supply. It may even spill water into the basement from the top of the
AVB each time the pump shuts off.
Meets ASSE Listed
1001, CSA Certified, IAPMO Listed
 | The
Basepump ejector is mounted on the ceiling above the sump pit, discharging
directly
outdoors.
Other types of water powered pumps are located in or just above the
sump itself and so, this design won't work with any of those types
of backup pumps. |
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The
suction pipe is open, allowing all the ground water to back drain
into the sump pit after each pumping cycle. The Basepump is mounted
8 to 10 feet above the sump pit.
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The
discharge piping is vented to atmosphere and empties 12" to 18"
below the Basepump. There is no backpressure on the Basepump
Ejector when it is not running.
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The
Basepump has an approved Atmospheric
Vacuum Breaker (AVB) factory installed downstream of the control
valve. (Refer to the photo above.)
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The
Basepump suction and discharge pipes are empty of sump
water unless the pump is operating.
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| Specify
the Basepump Model you want and then order the -AVB add-on.
When it comes, it will be designated like this: E.g. RB750-AVB. |
| The
AVB add-on cannot be used with the SDK type of installation at all.
If they are ordered together by mistake, we will change the order to a
standard model pump with an AVB add-on.
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To place an order NOW for this pump with the -AVB Add-on, click
this link to our ordering page.
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The Basepump system design meets the criteria as specified by the University
of
Southern California
as outline below.
AVB
is always placed downstream from all shut-off valves. Its air inlet valve closes when the water flows in the normal
direction but, as water ceases to flow the air inlet valve opens, thus
interrupting the possible back siphon effect.
If piping or a hose is attached to this assembly and run to a
point of higher elevation, the backpressure will keep the air inlet
valve closed because of the pressure created by the elevation of water.
Hence, it would not provide the intended protection. Therefore, this type of assembly must always be installed at
least six (6) inches above all downstream piping and outlets.
Additionally, this assembly may not have shut-off or obstructions
downstream. A shut-off valve
would keep the assembly under pressure and allow the air inlet valve (or
float check) to seal against the air inlet port, thus causing the
assembly to act as an elbow, not a backflow preventer. The AVB may not be under continuous pressure for this same
reason. An AVB must not be in
use for more than twelve (12) hours out of any twenty-four (24) hour
period. It may be used to
protect against either a pollutant or contaminant, but may only be used
to protect against a back siphon condition.
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