Close low point drain valves when water stops flowing.

2. Clean clapper facings and seats.

3. Clean the valve interior.

4. Place clappers on seats and make certain the antiwater column latch is in place. Bolt on the cover. Do not use grease or other material to help seat clappers. Fill the system with 10 psi air pressure to blow out any residual water through low point drains.

5. Open valves at the top and bottom of the priming chamber and priming test valves.

6. Admit water to the priming chamber until water flows out of the test valve. Close this valve.

7. Close the priming chamber valves.

8. Admit air pressure to the system.

9. Open the main control valve slowly.

10. Close the main 2-inch drain valve, except where water hammer conditions exist. In this case, leave the 2-inch drain valve open until pressures stabilize.

To check air supply piping, do the following:

Note air pressure within 12 to 24 hours after resetting the dry pipe valve. If air leakage exists, test sprinkler piping for leaks.

Make sure the valves to manually operated compressors are tightly closed. A slow air leak back through one of these valves can trip the dry pipe valve.

Examine restriction orifices in air piping and air pressure regulators, if used, from automatic air compressors to dry pipe valves.

Deluge and Pre-Action Valves

To test deluge and pre-action valves, perform the 2-inch drain test quarterly by opening the 2-inch drain valve fully and recording pressure at lowest point. Close the 2-inch drain valve and record pressure at the stabilization point. Notice whether pressure returns quickly or slowly. Main- tain a continuous record of drain tests.

If the recorded pressure when the valve is wide open is similar to previous recordings and pressure returns quickly, it is normal.

If the recorded pressure when the valve is wide open is significantly lower or pressure is slow to return when the valve is closed, there may be an obstruction in the waterway. Check for partially closed valves to the sprinkler system. Check the water pressure and the local water-flow alarm through the bypass connection.

Some deluge systems have both open and closed sprinklers. Make sure heat-responsive devices are provided in areas with both open and closed sprinklers and are in service. Fusing of a sprinkler will not operate a deluge valve. Where conditions permit, trip-test each deluge valve every 3 years by flowing water through the heads/ nozzles. To conduct a deluge valve dry trip-test, do the following:

1. Close the main control valve.

2. Apply an electric heat lamp to at least one heat-actuating device in each circuit, testing one circuit at a time. Note the time required to trip the valve. Where flammable vapors may be present, use a hot cloth or hot water in place of the electric test set.

3. Reset the deluge valve and trip, using the manual release.

4. Where fixed temperature releases are involved, wait 15 minutes and trip by removing a fusible element from the tubing or a heat- responsive device.

5. When tests are complete, reset valves and open the main control valves.

Because there are so many designs of heat- responsive devices, test procedures for each cannot be included here. See the individual manufacturer's information for detailed testing procedure. During routine inspections, check for painted or corroded contacts, plugged vents, or painted domes. Clean or replace affected devices.

Cathodic Protection Equipment

Inspect cathodic protection equipment as follows:

1. While equipment is operating, note and record current flow shown by meters. If there is no current, check for blown fuses, electrodes touching the tank, ground-wire connection to tank, or electrodes not immersed in the water. If equipment operates at voltages or amperages over those listed on the nameplate, the rectifier may be damaged. Check polarity and direction of current flow. (If connections to rectifier are reversed, rapid damage to the tank occurs.)

2. Check condition of electrodes that deteriorate because of action of current passing from electrodes to water. Replace worn electrodes. (Watch for diminishing current flow on the ammeter; this is a sign that the electrodes may be failing.)