Chapter 7: Maintenance, Testing & Trouble shooting Flashcards
When would you need to go for recertification for CCC?
in 5 years
- membership is renewed every year
a 3 valve differential pressure gauges needs what?
1) 15 psid gauge differential pressure gauge
2) needs to be tested annually
3) Low pressure side hose needs to be needle valves
What does a 5 valve pressure gauge include:
1) low side bleed valve
2) high side bleed valve
3) 2 air bleed valves
What is used to test backflow preventers that have a leaky shut off 1?
Bleed - off valve
What does the sight tube method need? (size of tube)
36” tube –> allows to fill 28” = 1 psi
What size is most common for an adaptor fitting?
1/4”
If a backflow preventer is removed does a jumper wire need to be supplied?
Yes
What is the min psi needed for an acceptable Buffer when testing an RP?
3psi (20.7 kPa)
What is the relief required operating pressure when testing an RP?
2 psi (13.8 kPa)
What is the Air inlet required operating pressure when testing an PVB?
1 psi (6.9 kPa)
How many days do you have to submit your report to AHJ?
30 days
Personnel engaged in testing backflow prevention devices must be?
Adequately trained and certified
How often must certified testers pass a recertification exam?
Every 5 years
An approved differential pressure gauge for testing backflow preventers must read from — psid to — psid and in increments of — psid.
1) 0
2) 15
3) .1 - .2
List 3 accessories which can often be found in testers kits and state what they would be used for.
Bleed off valve: bleed off excess water passing through a leaky
shutoff valve (establishing static conditions)
Water Column Sight Tube: establish a pressure based on a column of water to provide force against check valves or air inlet valves to determine their proper operation, or to bring a low mounted test cock to the highest
point of the assembly
Test Cock Hose Adapter fittings: Allow for connections of the gauge to the test cocks in the event that the adapters on the assembly to be tested have
been removed or damaged
Who has the responsibility to ensure that backflow preventers are maintained in good working condition?
The owner of the building/premise (the owner of the assembly).
Why would a jumper wire be necessary for a bypass when removing a backflow preventer from a water service?
To allow any current-to-ground that may be in existence.
Why is removal of a backflow assembly for testing or repair unnecessary?
Because to gain certification they must be “in-line testable” and serviceable
When are backflow preventers required to be tested?
1) after install
2) Annually
3) Backflow preventer relocated
4) Supply line piping is altered
5) Routine maintenance
6) Backflow repaired
7) Backflows installed prior to CCC program
8) AHJ requested
9) Detector type backflow preventer (RPDA or DVDA)
What 2 things is a tester required to fill out after performing a test and whose responsibility is it to pay for testing / repairs or maintenance?
The tester is required to fill out the Testing and Inspection Report (sent to the CCCP administrator) and the test tag (affixed to the unit tested). The
owner of the device is responsible for the costs of testing, overhaul and
maintenance.
What are the preliminary procedures prior to testing any backflow preventer?
Notify, Identify, Inspect, Observe (7.11)
State the purpose and pass/fail criteria for test #1 of an RP
-Test the relief valve opening point
-The relief valve shall open when the differential pressure across C.V. 1 is 2PSI (13.8kPa) or higher
What is the probable cause of the relief valve not opening during test #1 of an RP after water is bypassed from the high side –> low side of hose?
If the differential drops to “0”, it is most likely that the relief valve is stuck in the closed position; if the differential doesn’t drop it is likely that shutoff #2 is leaking
State the purpose and pass/ fail criteria for Test #2 of an RP
-Test that C.V. 2 closes tight in the reverse direction of flow
-The C.V. 2 shall close tight, holding a differential pressure for at least 2min
What is the probable cause of the relief valve discharging after bypassing full pressure to the downstream side of check valve #2?
Either check #2 is fouled or the normal pressure in the zone wasn’t re-established prior to pressurizing the downstream piping through test cock
#4 and the slight disc compression caused the relief valve to open
How is the cause of discharge in the above question determined?
Slightly unthread the low side hose connection to test cock #3 then retighten. If relief valve discharges again, check #2 is leaking. If it doesn’t, the culprit was disc compression.
State the purpose and pass/fail criteria for Test #3 of an RP
-Test that C.V. 1 closes tight in the direction of flow
-The C.V. 1 shall close tight, holding a differential pressure for at least 2min
-The differential pressure across C.V. 1 shall be at least 3PSI (20.7kPa) higher than the relief valve opening point (3PSI buffer)
What is the min expected “buffer” that is recorded in Test #3 and what does the buffer represent?
Minimum buffer is 3 psid, and it represents the amount of pressure loss that could occur in the system piping upstream of the assembly when it is in a static condition, without causing the relief valve to trip.
What does the gauge reading in Test #3 represent?
The actual static pressure drop across check #1
In Test #3, why would the differential pressure reading fall / the relief valve open?
Check #1 is leaking
State the purpose of Test #4 of an RP
-To record static pressure at the time of the test (upstream of C.V. 1)
What is the probable cause of an RP continuously draining from the relief port?
It is most likely that the relief valve is fouled. If it drains continuously only in a static condition it is likely the #1 check is fouled. Least likely is that check #2 is fouled with backpressure.
What is the probable cause of a discharge from the relief port of an RP after the #2 shutoff valve has been closed?
Most likely is that check #1 is fouled.
Why should water discharge from the relief port after closing both shutoffs and opening test port #2?
You have released the pressure from the sensing line that is holding the relief valve closed against the pressure of the zone combined with the relief
spring pressure. It will open wide immediately after opening test cock #2.
This sequence can be used to flush suspected debris out of the relief valve.
State the purpose and pass/fail criteria for Test #1 of a DCVA
-Test that C.V. 1 closes tight in the direction of flow.
-The C.V. shall close tight, holding a differential pressure of at least 1PSI (6.9kPa) for at least 2mins
State the purpose and pass/fail criteria for Test #2 of a DCVA
-Test that C.V. 2 closes tight in the direction of flow.
-The C.V. shall close tight, holding a differential pressure of at least 1PSI (6.9kPa) for at least 2mins
State the purpose of Test #3 of a DCVA
-To record static pressure at the time of the test (upstream of C.V. 1)
Where must the differential pressure test gauge be held during all tests of the DCVA?
Gauge must be held at the same height as the test cock downstream of the
C.V. being tested (and all unused hoses must be removed or wrapped around the gauge).
When testing the check valves of a DCVA, what can be done if water continues to flow from the test cock downstream of the check valve being tested?
The centerline of the gauge can be lowered to the centerline of the backflow preventer and the test carried out as usual
When testing the check valves of a DCVA, what can be done if the water level continues to drop in the sight tube attached to the test cock downstream of the check valve being tested?
The bleed-off valve can be opened so that the water flowing out of the sight
tube (or test cock) is at a minimum and the test carried out as usual.
State the purpose and pass/fail criteria for Test #1 of a PVB
-Test the Air Inlet Valve opening point.
-The air inlet valve shall begin to open when the internal pressure in the valve is 1PSI (6.9kPa) or more above atmospheric pressure (and be fully
open when the water drains from the body).
State the purpose and pass/fail criteria for Test #2 of a PVB
-Test that the C.V. closes tight in the direction of flow.
-The C.V. shall close tight, holding a differential pressure of at least 1PSI (6.9kPa) for at least 2mins
State the purpose of Test #3 of a PVB
-To record static pressure at the time of the test (upstream of C.V.)
State the purpose and pass/fail criteria for Test #1 of a SRPVB
-Test that the C.V. closes tight in the direction of flow.
-The C.V. shall close tight, holding a differential pressure of at least 1PSI (6.9kPa) for at least 2mins
State the purpose and pass/fail criteria for Test #2 of a SRPVB
-Test the Air Inlet Valve opening point.
-The air inlet valve shall begin to open when the internal pressure in the valve is 1PSI (6.9kPa) or more above atmospheric pressure (and be fully
open when the water drains from the body).
State the purpose of Test #3 of a SRPVB
-To record static pressure at the time of the test (upstream of C.V.)
What is the standard min time duration when determining whether or not a check valve passes or fails?
All observances of pressure (and of the gauge needle settling) are to be 2 minutes.
If one test on an assembly fails, does the entire assembly fail?
Yes. If the check valves or air inlet/relief fail the entire assembly fails.
(Assemblies are not failed for leaking shut-off valves)
What purpose does a backflow preventer test form sheet serve?
It serves to monitor the testing and performance of the assemblies.
What is the purpose of “blowing down” test cocks on an assembly?
To remove any foreign material.
State the purpose and requirement of Tests #1, 2 and 3 of a DCVA using a sight tube
Checks #1 and #2 shall close tight in the direction of flow for a minimum period of 2 minutes with the inlet pressure at least 1 psi and the outlet at atmospheric pressure
What is the min height of a column of water necessary in a sight tube for testing a backflow preventer using the sight tube method?
28” of water column (711mm) to generate the 1PSI of pressure that the C.V. must hold.