Well pumps · pressure system
Tank tee kits explained
On most private wells, the pressure tank does not connect to the house with a plain pipe. It sits on a short manifold called a tank tee — a single fitting that gathers the pressure switch, gauge, drain, and relief valve in one place right at the tank. Knowing what each port does makes it easier to read your system, spot a failing part, and buy the right kit when a contractor replaces a tank.
Bottom line
A tank tee kit puts the pressure switch, pressure gauge, drain valve, and pressure relief valve on one manifold at the tank inlet, usually with a union so the tank can be swapped without cutting pipe. Match the tee to your tank connection and pipe size, use parts rated for potable water, and make sure the relief valve is set below the tank’s maximum working pressure. Tank and switch work involves line-voltage wiring and stored pressure, so a licensed well contractor is the right call for most replacements.
What sits on a tank tee
| Part | What it does | What to know |
|---|---|---|
| Tee body | Main run from the well line to the house, with a branch to the tank | Brass or stainless; sized to your tank connection and pipe |
| Union | Lets the tank or tee come off without cutting pipe | Makes later tank replacement much simpler |
| Pressure switch port | Feeds tank pressure to the switch that starts and stops the pump | Small port that can clog with iron or sediment — see pressure switch guide |
| Pressure gauge port | Shows system pressure | Usually 1/4-inch NPT — see well pressure gauges |
| Drain (boiler drain) valve | Drains the tank and lets you relieve pressure for service | Used for precharge checks and part swaps |
| Pressure relief valve | Opens if pressure climbs dangerously high (for example, a stuck switch) | Set above normal cut-out and at or below the tank’s maximum working pressure; pipe the outlet where discharge is safe |
Why it is built this way
- The switch reads the tank, not the far end of the house. Mounting the switch at the tank keeps cut-in and cut-out readings stable and avoids short cycling from pipe friction.
- Everything for service is in one spot. Gauge, drain, and switch side by side make diagnosis quick.
- Fewer joints. A one-piece manifold has fewer threaded connections to leak than a field-built nest of fittings.
- Safety. The relief valve protects the tank and plumbing if the switch contacts weld shut and the pump keeps running.
Choosing a kit
- Tank connection and pipe size. Many residential tanks and supply lines use a 1-inch connection, but check your tank’s label and pipe before ordering.
- Material. Lead-free brass or stainless, listed for potable water.
- What is included. Some kits include the gauge, drain, and relief valve; few include the pressure switch. Read the parts list.
- Relief valve rating. Confirm the setting fits between your cut-out and the tank’s maximum working pressure.
- Constant-pressure systems. A variable-speed setup such as a Grundfos SQE with a CU controller uses a pressure sensor instead of a mechanical switch and often a smaller tank; follow that system’s install guide — see SQ vs SQE constant pressure.
Signs a tee or its parts need attention
- Drips or mineral crust at the tee, union, or drain valve.
- Relief valve weeping — pressure may be climbing too high, or the valve itself is worn. Treat it as a warning, not a nuisance.
- Gauge and switch acting erratically at the same time — the shared ports may be clogged with scale or iron.
- A tank replacement is planned — a fresh tee kit and union are often installed at the same time.
When to call a pro
- The tank, tee, or switch needs replacing — the job combines line-voltage wiring, stored pressure, and potable plumbing.
- The relief valve opens or weeps.
- You are moving to a constant-pressure pump or changing the tank size — a licensed well contractor should design it.
Getting help
Start with a licensed well contractor for tank, tee, and pressure-system work. For Grundfos residential well pumps and pump questions, R.E. Merrill & Associates has handled industrial and municipal pumps and fluid systems since 1987 — contact R.E. Merrill & Associates.
Related across the site
- Iron in well water — the iron that clogs tank tee switch and gauge ports
- Leak sensors for the basement, softener, and well tank — catch a leaking tank tee early
Sources
- Pressure tank and pressure switch manufacturer installation guides — tank connections, relief valve and maximum working pressure guidance.
- Grundfos residential well pump documentation — pressure system basics and constant-pressure alternatives.