PVB , SVB & DC Flashcards
What is the critical level of a PVB?
12 inches above the downstream use
What can be done if the air inlet of a PVB will not seat?
Increase the supply pressure
Two areas were a PVB shouldn’t be installed?
In a pit or area with toxic fumes
How should a PVB be installed?
upright & plumb
A PVB is rated for what type of hazard and backflow?
High hazard & low hazard
Backsiphonge only
What is the maximum pressure drop across a PVB?
10 PSI
What is the minimum PSID for the check of a PVB?
1 PSID
What is the minimum PSID that the air inlet valve of a PVB must open out ?
1 PSID
How many test cocks are part of the PVB assembly?
Two Test Cocks
Where are the shut off valves located on a PVB assembly?
Inlet & Outlet
Can a PVB be subjected to continuous pressure?
Yes
The # 1 test cock of a PVB assembly is located where in relationship to the #1 shutoff?
Downstream
The hydraulic purpose of any PVB is to stop a__________.
Siphon
An indication that a pressure vacuum breaker is undersized for its application is
chatter or noise during flow
When using the one hose test on a PVB ,how many of the shut off valves must be closed?
Both
Pressure vacuum breaker shut offs and test cocks will avoid freeze damage if winterized by________________
rotating the ballvalves handles to a 45 degree angle
If not marked , a pressure vacuum breaker’s critical level is
the bottom of the valve body
What is the most common use for a pressure vacuum breaker?
Irrigation system
A spill -resistant vacuum breaker’s check valve must be drip tight at ____ PSID.
1 PSID
The required minimum number of resilient seated valves in an SVB is
two
The closing & opening pressure of a spill-resistant vacuum breaker’s vent valve is _____PSID
1 PSID
An SVB ‘s critical level must be above the downstream use by at least _____ inches?
12 inches
A spill- resistant vacuum breaker assembly has how many test cocks?
one test cock
The SVB may be subjected to _______ water pressure.
continuous
