Reading 9013FSG2J21 field by field
| Field | In 9013FSG2J21 | What it means |
|---|---|---|
| Class | 9013 | Square D Pumptrol pressure switch family |
| Type | FSG | S = standard, adjustable differential. T = non-adjustable differential. Y = higher HP, adjustable differential. R = reverse action. |
| Enclosure | FSG | G = NEMA 1. W = NEMA 3R (so a 9013FSW is the 3R version; Square D notes it must be mounted vertically to keep the 3R rating). |
| Fluid connection | 2 | 1 = 1/8" NPSF internal, 2 = 1/4" NPSF internal, 9 = 1/4" NPT external, 10 = 1/4" barbed bayonet, 20 = 90° elbow 1/4" bayonet. 42 and 49 are narrow-differential versions on the 2 and 9 connections (on the FSG: cut-out 9–30 psi, cut-in 3–10 psi; other types are listed with different ranges). |
| Pressure code | J21 | Factory setting, cut-in/cut-out: 30/50 psi (see the full code list below) |
| Forms (options) | none | Extra letters at the end, such as M1, M4, P or Z22 (see below) |
Pressure codes
| Code | Factory setting |
|---|---|
| J15 | 5–21 psi |
| J16 | 8–20 psi |
| J20 | 20–40 psi |
| J18 | 20–50 psi |
| J21 | 30–50 psi |
| J24 | 40–60 psi |
| J33 | 50–70 psi |
| J34 | 55–85 psi |
| J25 | 60–80 psi |
| J99 | Pressure settings specified on the order |
Square D notes that a code existing in the list "does not imply that the code is available for any or all devices": the setting has to fall inside the limits of the specific switch type. For a standard 9013FSG2, those limits are in the next section: J33, J34 and J25 have cut-outs above its 65 psi top, and J16's 12 psi differential is below its 15 psi minimum.
What a 9013FSG2 can be set to
| Cut-out (adjustable) | 20–65 psi |
| Cut-in (adjustable) | 5–45 psi |
| Differential (cut-out minus cut-in) | 15–30 psi |
| Maximum permissible pressure | 65 psi |
| Repeat accuracy | ±3% of the range |
Versions with the M4 low-pressure cut-off (below) are listed separately, with a narrower range: cut-out 34–65 psi, cut-in 19–45 psi, differential 15–30 psi.
So a J21 (30/50) and a J24 (40/60) are the same switch body with different factory settings, and either can be adjusted within these limits. A target like 50/70 is outside them: the cut-out tops out at 65 psi. Square D also says system pressure should never exceed the upper limit of the range in normal operation, because it greatly reduces diaphragm life. To change settings on an adjustable switch, see the adjustment guide.
Option letters you'll see at the end
| Letter | Meaning |
|---|---|
| M1 | Maintained manual cut-off lever (AUTO / OFF) |
| M4 | Low-pressure cut-off (AUTO / START / OFF): opens the contacts at about 10 psi below cut-in and turns the pump off |
| P | Pulsation plug, for surges from high-speed jet pumps or fast-closing valves |
| Q | Salt-water metal flange (1/4" NPSF internal only) |
| Q8 | Plastic flange, 1/4" NPSF internal only (max. 120 °F, max. 80 psi) |
| T / T1 | 1/2" conduit bushing on the left / on the right |
| U / U2 | Slip-on connections on the load terminals only / on line and load terminals |
| Z22 | Black cover |
The one that matters most for a homeowner is M4. A 9013FSG2J21M4 is a 30/50 switch that also shuts the pump off when pressure falls about 10 psi below cut-in. Square D gives a low-water condition as the example of why system pressure would be lost. Its lever is marked AUTO, START and OFF. If your old switch has M4 and the new one doesn't, you lose that shut-off. If a pump with an M4 switch "won't turn on", see the troubleshooting guide.
Motor size limits
| Type | 115 V | 230 V |
|---|---|---|
| 9013FSG / FSW | 1.5 HP | 2 HP |
| 9013FTG | 1 HP | 1 HP |
| 9013FYG | 2 HP | 3 HP |
Square D positions the FYG for larger pumps, and says its higher-HP switches can also run the control circuit of a magnetic starter for pumps bigger than they control directly. Whether that applies to your pump is an electrician's call.
Matching a replacement
Compare the old switch's number field by field: the type letter (S, T or Y), the enclosure letter (G or W), the full fluid connection code, the pressure code, and any option letters. Watch for 42 or 49 in the connection position: those are narrow-differential switches (a 9013FSG42 or FSG49 is listed at cut-out 9–30 psi, cut-in 3–10 psi), not a standard 2 or 9. The pressure code only sets the starting point on an adjustable switch, but the type letter, connection and options are physical differences. If the label is unreadable, our well pump picker starts from your house and pump instead.