
146 DUCHAINE BLVD. , NEW BEDFORD, MA. 02745-1292 TEL. 508- 995-9711 FAX 508-995- 5021 E-MAIL pumps@edsonintl.com
How The Pump Works
lThe air cylinder housing raises and lowers the diaphragm.
lRaising the diaphragm creates a vacuum.
lThe vacuum forces the discharge valve assembly closed.
lAtmospheric pressure pushes liquid and/or air up the inlet plumbing to fill the vacuum.
lWhen the diaphragm is driven down the air and liquid under the diaphragm is compressed
closing the inlet check valve and forcing the air and liquid out the discharge.
lThe closing of the inlet valve assembly also prevents the liquid and air trapped in the
inlet line from dropping back down (to atmosphere).
Inlet Valve Assembly:
opens into the pump
Discharge Valve Assembly:
closes and seals on the valve
seat that is part of the pump
base under the discharge
chamber.
Suction Stroke Discharge Stroke
Discharge Valve Assembly:
opens away from the pump
Inlet Valve Assembly:
closes and seals on the valve
seat that is part of the inlet
chamber.
P-220A-03
lVolume Test -Tests overall performance of the pump installation.
1.Use a container with a known capacity of at least 2 gallons.
2.Empty the container using the suction side of the pump or fill it from the discharge.
When using the fill test make sure the pump is fully primed before filling the container.
3.Use a watch to record the time it takes. Repeat the test at least twice.
4.Establish GPM rate. Example 1: It took 10 seconds to fill a 5 gallon container. The
GPM rate is 30 Gallons Per Minute.(60 seconds divided by 10 seconds times 5 gal.)
Example 2: It took 10 seconds to empty a 2 gallon container. The GPM rate is 12
Gallons Per Minute.(60 seconds divided by 10 seconds times 2 gal.)
5.Record the cycle speed of the pump. Know the head conditions of your test and
compare the results of your test with the volume of the appropriate Volume Chart
on page 2. Every installation is different so use the charts as a guideline.
6.Example 1: The “fill test” at 30 GPM. The diaphragm is going up and down at 56
cycles per minute. The pump is approximately 6 ft. above the liquid. I disconnected the
installation discharge line and replaced it with a 3 ft. length of 2” hose so I could do the
fill test. Using the 56 cycle per minute Volume Chart from page 2, I know that at a
suction height of 5 ft. and a discharge height of between 0 and 5 ft. I should get
approximately 30 GPM. The installation is performing within the guidelines.
6.Example 2: The “empty test” at 12 GPM. The diaphragm is going up and down at 30
cycles per minute. The pump was approximately 5 ft. above the 2 gal. container and
the discharge line goes up 4 ft. From the 30 cycle per minute Volume Chart on page
2, I know that with a suction height of 5 ft. and a discharge height of 0 to 5 ft. I
should get approximately 17 GPM. The installation is performing below the
guidelines. See the Trouble Shooting section of this manual.
lVacuum Gauge Test - Tests the performance of the discharge valve and valve seat.
1.Attach a 5’ length of non-collapsing hose or pipe with a vacuum gauge installed
to the inlet of the pump. Make sure the line is completely sealed and air tight.
2.Turn on the pump and let it run till the gauge stabilizes. Record the reading.
3.Turn off the pump and watch the gauge.
4.If the discharge is working properly the gauge should build and hold at 10” to 12”hg.
Do not be concerned if the vacuum pressure slowly returns to 0 within a minute or so.
5.If you do not get any vacuum reading or if the gauge does not get to 10” hg and drops
off to 0 as soon as the pump stops, do the same thing again. Listen for air being
sucked in around the diaphragm. If you hear air movement, inspect for loose bolts or
worn diaphragm. If you hear no air movement, remove the discharge chamber and
inspect the valve assembly and valve seat. Clean or replace the valve and clean or
resurface the valve seat as appropriate. See Maintenance/Valve Assemblies
Pump Performance Tests:
Page 7 Operation Guidelines- Testing