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Instruction Manuals: Pressure Testing

Complete pressure testing of plumbing systems involves a two step process. The first step; a water test, is performed in order to isolate the section of plumbing that is leaking. The second step; an air test, is performed in order to pinpoint the exact location of the leak. For each test, well maintained, quality equipment and careful deliberate set up will increase the safety and accuracy of your test.

Equipment Needed:

  • Anderson Pressure Tester
  • Assorted Anderson Test Plugs
  • Regulated Air Source (1/2 H.P. or larger air compressor or air tank)
  • Air and water hoses
  • Listening Device such as Geophones or their electronic counterpart are strongly suggested. With practice these enable you to more accurately locate leaks than just your unaided ear. Contact Anderson Manufacturing Company for more information.

Set Up:

Turn off pump and heater before performing any pressure test. Identify all openings of the section of pipe you will be testing. All but one of these holes must be plugged. Different types of plugs will allow you to plug virtually any opening you encounter in a pool.

Here are some suggestions: Skimmers, T's, Therapy Heads & Scum Gutters - Extender plugs.

  • Once it is determined which line is leaking, purge the line of water. Hook you pressure tester up to your gas source and slowly induce the gas into the line. Although a constant flow of gas is required, it is not necessary to maintain a measurable pressure.
  • Return Line w/ female threads - Hook Plugs
  • Miscellaneous fittings or cut ends of pipe - Standard Plugs
  • Odd shaped or off-round holes - Inflatable Plugs

An open stem plug with a quick connect attachment, to allow hook up to your pressure tester, should be inserted in the one remaining unplugged hole. This hole should be on the high side of the plumbing line. Water or air will be introduced from your pressure tester through this plug. Now attach your pressure tester to the plug and your water and air source to your pressure tester. You are now ready to go.

Water Test:

The initial test of a line should be done with water. A pressure drop is easy to observe when using water due to the fact that water does not compress, so any loss in volume will show itself quickly as a loss in pressure. Introduce water into the system by turning the valve handle towards the water line. You will be able to control the amount of water entering the system by moving the handle. Since the pressure gauge will show an inaccurate reading when water is flowing, occasionally turn the valve handle to the off position, straight up or down to check pressure. Bring the pressure to no higher than 20 p.s.i. If the pressure gets higher than this, release it by turning the black bleeder valve behind the pressure gauge. Once you have reached apx. 20 p.s.i. turn the valve to the off position. If the line holds pressure for two minutes there is not a problem leak in the section you are testing. If pressure does drop, check to make sure all plugs are secure, and test again to confirm leak. Release any pressure from the system by opening the bleeder valve after this test is complete.

Air Test:

You will need either a regulated air compressor or an air tank with a single stage regulator to perform this test. A 1/2 horse compressor is generally adequate. As far as tanks go, we recommend Nitrogen because it is cheap and does not freeze up as CO2 may. Another alternative for certified divers is a scuba tank that has been adapted to connect to the pressure tester. Each of these options offer distinct advantages and disadvantages. The compressor never needs refilling, but may make listening for the leak difficult because of the noise it creates. The air tank is quiet, but will need to be refilled occasionally.

Adjust the regulator on your air source to maintain a constant pressure of no more than 20 p.s.i. Now allow air into the system by moving the handle towards the air line and leaving it open. You must maintain a constant pressure of no more than 20 p.s.i. in the system even as the air escapes from the leak.

By systematically listening at two foot intervals along the path of buried lines you should be able to hear vibrations caused by the air leaking into water saturated soil. Once you hear a "bubbling - gurgling" noise, shorten the distance between readings. The leak will be directly beneath the place where the noise is the loudest. To confirm that the noise you are hearing is indeed a leak, turn off the pressure and listen in the same spot. If you do not hear anything when the pressure is off but do when it is on, you have found a leak.

If pressure cannot be maintained with just air, or if soil does not stay saturated, add a constant stream of water from the low end of pipe while adding air from the high end.

Safety Rules:

  • Never exceed 20 p.s.i. pressure
  • Only keep system under pressure when testing is being done
  • Stand clear of plugged openings when system is under pressure
  • Never use an unregulated air source
  • Use well maintained equipment - especially plugs, gauges and regulators