Why it matters
The FSG2J21CP is the Square D Pumptrol pressure switch found on many wells: it starts the pump at 30 psi and stops it at 50 psi, with contacts that open on rising pressure.
It fits jet, submersible and reciprocating pumps through a 1/4 in connection and is rated IP54.
Who it's for, and who should skip it
Good fit if
- 30/50 systems
- Replacing a worn switch
- Jet and submersible pumps
Look elsewhere if
- 40/60 systems (use the 40-60 model)
- Owners not comfortable with line-voltage wiring
Pros and cons
Pros
- Industry standard
- Adjustable
- Low price
Cons
- Line-voltage wiring
- Contacts wear over time
- 1/4 in connection only
Limitations to weigh
- Turn the power off at the breaker before opening a pressure switch; the contacts carry line voltage.
- Set the tank's air pre-charge 2 psi below the pump's cut-in pressure (28 psi for a 30/50 switch, 38 psi for 40/60) with the water off.
Specifications
Every figure below comes from the source shown in brackets. Where the maker doesn't state something, we say so instead of estimating.
| Amps | 30 A | Retailer |
|---|---|---|
| Voltage | 240 V | Retailer |
| Switch | Pressure switch | Retailer |
| Material | Metal | Retailer |
| Dimensions (seller) | 4 x 4 x 3 inches | Retailer |
| Mounting / installation | Wall Mount | Retailer |
| Compatible devices | Water pumps (Jet, Submersible, Reciprocating), Air compressors | Retailer |
Alternatives worth comparing
More well pumps & tanks we cover
Final verdict
The safe replacement for a 30/50 well.
Where to buy
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Questions buyers ask
What are the cut-in and cut-out pressures?
30 psi on, 50 psi off.
What pumps is it for?
Jet, submersible and reciprocating pumps.