Well pressure tanks and switches
Square D FSG2J21M4CP Pressure Switch with Low Pressure Cutoff, 30 to 50 PSI: published specifications
Quick answer
The Square D FSG2J21M4CP Pressure Switch with Low Pressure Cutoff, 30 to 50 PSI publishes 3 specifications and currently lists at $39.49. cut in pressure 30 PSI, cut out pressure 50 PSI, low pressure cutoff Yes. Every figure below is the manufacturer own, and nothing on this page is estimated.
Adds a low pressure cutoff, which shuts the pump down if the well runs dry instead of letting it burn itself out.
This sheet exists because comparing two pieces of water treatment equipment usually means opening two listings in two tabs and reading past the marketing. Everything Square D publishes for this unit is in one table below, followed by the same figures for the nearest alternatives in its category.
Published specifications
Square D publishes 3 figures for the Square D FSG2J21M4CP Pressure Switch with Low Pressure Cutoff, 30 to 50 PSI.
Published figure A published standard, regulatory limit, unit conversion or manufacturer specification. It does not change because somebody disagrees with it.
| Specification | Value |
|---|---|
| Cut in pressure | 30 PSI |
| Cut out pressure | 50 PSI |
| Low pressure cutoff | Yes |
What the manufacturer says
The listing bullets below are the manufacturer own words, reproduced rather than paraphrased so that anything claimed here can be attributed to them rather than to us. Marketing language in this category is unusually loose, and a claim that a unit is certified is worth checking against a standard number and a specific claim.
These are Square D own claims for the Square D FSG2J21M4CP Pressure Switch with Low Pressure Cutoff, 30 to 50 PSI, quoted rather than rewritten.
Published figure A published standard, regulatory limit, unit conversion or manufacturer specification. It does not change because somebody disagrees with it.
| Manufacturer claim |
|---|
| For use with water-supply systems |
| 1/4" - 18 NPSF internal thread opening |
| Turns on at 30 psi and off at 50 psi |
| For use with submersible well pumps or as a replacement switch |
| For electrically driven water pumps |
Against the nearest alternatives
The closest products by price in the same category, with the same published figures side by side. A cell reading "not published" means that maker does not state the figure, which is frequently the most useful thing on the row.
| Specification | Square D FSG2J21M4CP Pressure Switch with Low Pressure Cutoff, 30 to 50 PSI | Square D 9013 FSG2 Pressure Switch, 30 to 50 PSI | Reliance Pre-Charged Well Pressure Tank, 20 Gallon | Amtrol Well-X-Trol WX-202 Well Pressure Tank, 20 Gallon |
|---|---|---|---|---|
| Price | $39.49 | $29.99 | $175.92 | $327.99 |
| Cut in pressure | 30 PSI | 30 PSI | not published | not published |
| Cut out pressure | 50 PSI | 50 PSI | not published | not published |
| Low pressure cutoff | Yes | not published | not published | not published |
| Rated capacity | not published | not published | 20 gallons | 20 gallons |
| Cartridge type | not published | not published | Diaphragm | Diaphragm |
Every figure above is the manufacturer own published specification. Where a maker does not publish a figure the cell reads "not published" rather than carrying an estimate. A blank in a certification row is the finding rather than a gap: a certification covers a specific claim under a specific standard, so a system with no standard number stated has not necessarily been tested for anything you are buying it to do.
What is not on this page
Anything Square D does not publish. We do not estimate a missing figure, interpolate one from a neighbouring model, or repeat a number from a forum. In this category the specifications are certified capacities and contaminant claims, and a reader comparing two products on a grid cannot tell a published certification from an estimate, so an estimate that reads as a certification is a safety problem rather than a gap.
In particular, no row on this page asserts what this unit removes unless the manufacturer states a certification and a standard number. A certification covers specific claims rather than the whole unit, so "certified" with no standard number attached is not a reduction claim and is not treated as one here.
If a figure you need is missing, it is missing from the manufacturer own listing, and the place to find it is the product manual or the maker technical support rather than any third party table.
Frequently asked questions
What are the Square D FSG2J21M4CP Pressure Switch with Low Pressure Cutoff, 30 to 50 PSI specifications?
Square D publishes 3 figures for this unit: cut in pressure 30 PSI, cut out pressure 50 PSI, low pressure cutoff Yes. Everything in the table above comes from the manufacturer own listing rather than from measurement or estimation, and anything the maker does not publish is left out rather than guessed at.
How much does the Square D FSG2J21M4CP Pressure Switch with Low Pressure Cutoff, 30 to 50 PSI cost?
It currently lists at $39.49, though prices in this category move constantly and the figure on the product page is the one that governs. Where two products are close on price, the specification table above is usually a better guide to which is right for your water than the difference between them.
Are these figures measured or published?
Published. Every number on this page comes from the Square D listing for this exact unit. We do not test equipment in person and we never claim to, and nothing here has been derived, interpolated or rounded from another model. That is also why some rows in the comparison table read "not published" rather than carrying a number.
Does this tell me what the unit removes?
Only where the manufacturer states a certification and a standard number. A certification covers specific claims rather than the whole unit, so NSF/ANSI 42 is aesthetic effects, 53 is health effects claim by claim, 58 is reverse osmosis and 372 is the lead content of the fitting rather than lead removal. Match the claim to your own laboratory result.
Is this the current model?
It is the unit at this listing, which is the most reliable way to identify a specific product in a category where model names get reused across generations. Manufacturers frequently sell several generations alongside each other, so check the model number in the title against the one you are comparing rather than relying on the family name.
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Researched, not professional advice. This page is compiled from published standards, regulatory limits, manufacturer specifications and owner-review consensus, not hands-on testing. Nothing here diagnoses a water problem or says any product makes water safe to drink. Figures described as a rule of thumb are water treatment trade convention rather than published standards, and they are labeled that way wherever they appear. Test your water before you buy equipment: on city water start with the Consumer Confidence Report your utility publishes each year, and on a private well only a certified laboratory test tells you what you have. Bacteria, nitrate, lead, arsenic and PFAS are not do it yourself topics, they are invisible and tasteless, and they need a laboratory and usually a licensed professional rather than a product. Remember that a certification covers a specific claim under a specific standard, so "NSF certified" with no number attached tells you very little.