Flojet 2100 Series Pump 50 PSI Switch Kit | Xylem

If your Flojet 2100 Series pump has started running when nobody's at the tap, or it won't shut off after the faucets close, the pressure switch is usually the part that's gone. This kit from Xylem puts that pump right. It's the replacement pressure switch for the 2100 Series duplex diaphragm fresh water pump, set to cut out at 50 PSI, and it comes with everything you need to finish the job in one sitting.

Here's what's in the box. A new 50 PSI pressure switch, two bypass poppets, two springs, and a set of wire leads. That covers the parts of the pump that actually wear out over time, so you're not chasing a second failure a month later. The 2100 Series is a duplex pump, meaning it has two pumping chambers working together, which is why there are two poppets and two springs instead of one. Replacing them as a set keeps both sides matched and your water pressure steady at the tap.

The pressure switch is the brain of an on-demand water system. When you open a faucet, pressure in the line drops and the switch tells the pump to run. Close the faucet, pressure climbs, and at 50 PSI the switch shuts the pump off and holds it there until you need water again. When that switch wears out, you get the classic symptoms. The pump short-cycles, clicking on and off every few seconds. Or it chatters at the tap. Or it just runs and runs and never shuts down, which wears the motor and drains your battery overnight. A fresh switch set to the correct 50 PSI brings that behavior back to normal.

Not sure the switch is the culprit? Here's a quick way to tell. Spin the pump up, open a tap to get flow, then close it. A healthy pump builds pressure and clicks off within a second or two. If it keeps buzzing, hunts up and down, or shuts off and then kicks right back on, the switch has lost its calibration and needs replacing. If instead the pump sounds rough, loses prime, or weeps from the body, that's a different problem and a switch kit won't cover it. Most of the time, though, a 2100 that won't settle down is a switch and bypass issue, which is exactly what this kit is built to address.

The bypass poppets and springs do the quieter work. They manage internal flow so the pump ramps smoothly instead of pulsing, and they're a big part of why a healthy 2100 feels steady at the faucet and a tired one feels jumpy. The poppets and their springs stiffen and lose their seal with age, so swapping them while you've got the pump apart is just good sense.

Installation is a straightforward bench-level repair. The wire leads are included so you can splice cleanly into your existing pump wiring instead of hunting for connectors. If you can run a screwdriver and make a couple of wire connections, you can do this. We'd suggest cutting power and relieving system pressure first, the usual drill before you open up any pressurized water component.

Who's this for? RV owners and boaters running a Flojet 2100 Series pump in a fresh water system that's starting to act up. If your pump is otherwise mechanically sound, the motor spins and the diaphragm holds but the behavior's gone wrong, this kit is almost always the fix, and a lot cheaper than a whole new pump. Just confirm your system runs at a 50 PSI shut-off before you order, since that's the set point this switch is built around.

One honest note. This is a repair and rebuild kit, not a complete pump. It restores a working 2100 Series that's developed a switch or bypass problem. If your pump's motor is dead or the housing is cracked, you'll want a full replacement pump instead. But for the most common failure, the one where a good pump just stops behaving, this is exactly the part you're after.