Dungs DMV-D/624 Instrukcja instalacji - Strona 6

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Valve Leakage Test

This leak test procedure tests the external sealing and valve

seat sealing capabilities of the DMV automatic safety shutoff

valve. Only qualified personnel should perform this test.

It is required that this test be done on the initial system startup,

and then repeated at least annually. Possibly more often de-

pending on the application, environmental parameters, and

the requirements of the authority having jurisdiction.

Setup

This test requires the following:

A) Test nipples installed in the downstream pressure tap port

of each automatic safety shutoff valve to make the required

1/4" hose connection in step 4.

B) A transparent glass of water filled at least 1 inch from the

bottom.

C) A proper leak test tube. An aluminum or copper 1/4" rigid

tube with a 45˚ cut at the end that is then connected to a

1/4" flexible hose of some convenient length provides for

a more accurate leakage measurement.

However, a 45˚ cut at the end of the 1/4" flexible hose will

suffice, but it will not likely be as accurate as the rigid tube.

D) For detecting external leakages, an all purpose liquid leak

detector solution is required.

Leak Test Procedure

Use the illustration below as a reference.

1. With the upstream ball valve open, the downstream ball

valve closed and both valves energized, apply an all pur-

pose liquid leak detector solution to the "External Leak-

age Test Areas" indicated in the illustration below, to any

accessories mounted to the safety valve, and to all gas

piping and gas components downstream the equipment

isolation valve, and the inlet and outlet gas piping of the

automatic safety shutoff valve. The presence of bubbles

Type

DMV-D(LE) 704/6x4

*Based on air and test conditions per UL 429 Section 29. (Air or inert gas at a pressure of 1/4 psig and also at a pressure of one and one-half times

maximum operating pressure differential, but not less than 1/2 psig. This test shall be applied with the valve installed in its intended position.)

Volume of bubble defined in Table 2 of FCI 70-2-1998.

Allowable Valve Seat

Leakage* up to 7 PSI inlet

628 cc/hr

indicates a leak, which needs to be rectified before pro-

ceeding.

2. Then, de-energize the burner system and verify that both

automatic safety shutoff valves are closed.

3. Close the upstream and downstream manual ball valve.

4. Using a screwdriver, slowly open the V1 test nipple (port 3

or port 4 ) by turning it counter clockwise to depressurize

the volume between the two valves, and connect the 1/4"

flexible hose to the test nipple.

5. Slowly open the upstream manual ball valve, and then

provide for some time to allow potential leakage to charge

the test chamber before measuring the valve seat leakage.

6. Immerse the 1/4 in. tube vertically 1/2 in. (12.7 mm) below

the water surface. If bubbles emerge from the 1/4" tube

and after the leakage rate has stabilized, count the number

of bubbles appearing during a 10 second period. (See

chart below for allowable leakage rates.)

7. Repeat the same procedure for valve V2 (port 5), except

that valve #1 needs to be opened.

After completing the above tests proceed as follows:

8. Verify that the downstream manual ball valve is closed,

and both automatic safety shutoff valves are de-ener-

gized.

9. Remove the flexible hose, and close all test nipples.

10. With the upstream manual ball valve open, energize both

automatic safety shutoff valves.

11. Use soapy water to leak test all test nipples to ensure that

there are no leaks.

12. If no leakage is detected, de-energize all automatic safety

shutoff valves, and open the downstream manual ball

valve.

If leakage values are exceeded, replace valve

immediately.

1/4" Flex Hose

1/4" Rigid Tube

G 1/8" Test Nipple

# 219008

# of Bubbles in 10 s

Air

Natural Gas

6 ... 9