How to Troubleshoot a Square D Pumptrol

Square D Pumptrol pressure switches are commonly found in many commercial and residential plumbing applications that require the regulation of water pressure. Although Pumptrol pressure switches are generally reliable, sometimes problems can develop with the switch or with the associated water system. If problems develop, some simple troubleshooting can help identify the root of the problem and may even prevent a costly house call from your plumber or electrician.

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Troubleshooting a Pumptrol pressure switch is relatively simple.

Step 1

Confirm that any fusible switches and circuit breakers feeding the Pumptrol pressure switch are functional and in the "On" position, and check for cut, pinched, or frayed wiring. If power is being properly fed to the switch and the switch still fails to actuate when the water pressure falls below the cut-in pressure, disconnect all power to the switch before continuing.

Step 2

Visually check the switch contacts for severe burning or pitting. According to the manufacturer's website, if burning or pitting is evident, replace the contacts with Square D part number 9998PC241 for 9013F models and part number 9998PC205 for 9013G models.

Step 3

If the switch contacts are in good condition, make sure that the entry to the switch diaphragm is not clogged with sand, debris or deposits. To do that, remove the switch body from the pipe and visually inspect the opening into the diaphragm, which is located on the bottom of the switch body. Clean out any obstructions.

Step 4

Reinstall the switch and check for proper operation. If the switch appears to operate but fails to maintain proper pressure, adjust the cut-in and/or the cut-out settings.

Step 5

To raise or lower the cut-in and cut-out settings while keeping the differential between those two settings constant, adjust the range nut. The range nut is the 3/8-inch nut that adjusts the larger of the two springs in Models FSG, FYG, FRG, and Type G Pumptrol switches. Models FTG and FHG have only one adjustment spring. Turn the range nut clockwise to increase the cut-in pressure and counter-clockwise to lower the cut-in pressure. Three and a half revolutions of the range nut will change both the cut-in and cut-out settings by approximately 10 psi.

Step 6

Adjust the differential nut if you want to raise or lower the cut-out setting while keeping the cut-in pressure constant. All but the FTG and FHG Pumptrol models will have that option. The differential nut is the 3/8-inch nut that adjusts the smaller of the two springs in Models FSG, FYG, FRG, and Type G switches. Turn the differential nut clockwise to increase the cut-out pressure and counter-clockwise to lower the cut-out pressure. Adjusting the differential nut will change only the cut-out setting while the cut-in setting remains unchanged.