How Do I Fix a Leaking Union Gasket at the Pump or Heater?

A union at the pump or in-line heater that keeps weeping after it has been tightened almost always has an over-tightened or displaced O-ring, and the fix is to take the union apart, re-seat the O-ring and reassemble it by hand rather than to keep turning the nut. In most cases nothing has to be replaced. This page gives the step-by-step routine for that job, how to confirm the union really is the source before you open it, and what to photograph if the water turns out to be coming from the pump housing instead. The wider map of every place water can appear under a tub is in Water Under or Behind the Tub: Finding the Source at Unions, Air Fittings, the Hand Shower, Drain Elbow and Supply Lines.

Why a Union Weeps, and Why More Tightening Makes It Worse

The unions at the hydro pump and the in-line heater are the joints an installer undoes and remakes when the tub is set in place, and they are also the joints most likely to shift in transit. Shipping vibration can loosen unions and air lines, which is why every Ella tub gets a fill test before the walls close. When one of these unions drips, the natural reaction is to tighten it, and when it still drips the reaction is to tighten it again. That is the wrong direction. A union that leaks after tightening usually has an O-ring that has been over-tightened or pushed out of its seat, and no amount of extra force will make a displaced O-ring seal. The water finds the gap beside it every time the pump runs.

Two things follow from that. First, the repair is a disassembly and a careful reassembly, not a tightening. Second, a drip at a union is an adjustment, not a defect. Ella's own pre-installation guidance calls a union drip found during the fill test a normal install-stage adjustment, and the same holds if it shows up later behind the access panel.

Confirm the Union Is the Source Before You Open It

Water that collects under the tub can come from several connections that sit close together, so isolate the source first. The routine below is the one the support team uses, and it is the same order given in Why Is Water Leaking Underneath My Walk-In Tub?.

1. Open the access panel and dry the whole cavity. Lay dry paper towels under the pump, the heater, the drain fittings and the faucet connections above.
2. Fill the tub with the pumps off and wait. If a towel gets wet now, the water is coming from the faucet base, a supply line, a drain stopper or the door, not from a union.
3. Run the hydro pump alone for several minutes and look at the unions at the pump and at the heater with a flashlight. Never start a pump until the water covers every jet, because running a pump dry causes permanent damage that is not covered.
4. If the towel under a union is the first one to get wet while the pump runs, you have found your joint. If the drip appears only while the tub is draining, the drain elbow or its gasket is the suspect instead, and Why Did the Drain Elbow Crack and What Replaces It? covers that repair.

Re-Seating the O-Ring, Step by Step

Ella does not send technicians, so this is a job for a local licensed plumber, and the support team can answer that person's questions by phone or email. The work itself is simple.

1. Drain the tub and switch the pumps off so the joint is not under pressure. Dry the union and the area beneath it so you can see fresh water later.
2. Loosen the union nut and separate the two halves of the joint. Do not force anything; the nut should come apart by hand or with light help once it is started.
3. Take the O-ring out and look at it. A displaced O-ring will be sitting out of its groove, twisted, or pinched on one side. An over-tightened one will have been squeezed out of position rather than flattened evenly.
4. Clean any debris from the seat and from the mating face, then set the O-ring back in its groove so it sits flat all the way around.
5. Bring the halves back together square to each other and run the nut up by hand until it is snug. Reassembling by hand is the point of the repair. If it needs a wrench to stop dripping, the O-ring has moved again.
6. At the in-line heater, confirm that the heater threads match the pipe threads before reassembly. A mismatched thread will never seat properly no matter how the O-ring sits.
7. Refill until the water covers every jet, put a fresh dry paper towel under the union, run the hydro pump for several minutes and inspect the joint again with a flashlight.

A union that stays dry after this test is fixed. If it drips again from the same place after a careful re-seat, photograph the union, the O-ring and where the water shows, and include your serial number when you open a ticket at ellasbubbles.com/support so the team can confirm what you need. Replacement parts ship under the parts warranty after verification; the labor is done by your plumber.

When It Is Not the Union at All

Two nearby spots are easy to mistake for a union leak. The first is the screw fitting where water enters the pump. The second is a seam of the pump housing itself. A leak from either of those is a pump part question rather than a re-seat, so do not keep taking the union apart. Dry the area, run the hydro pump alone, and watch whether the first bead of water forms at the union nut or along the body of the pump. Photograph the exact spot with the water visible and send it with your model and serial number. The serial label is behind the magnetic access panel next to the door.

Braided supply lines are the other common look-alike, because water running down from a faucet connection above can pool near the pump. Check the braided lines along their full loop and the connections under each faucet piece with the diverter in both positions, since some fittings only see pressure in one position. A slow drip at a braided line loop means the line should be replaced rather than tightened further, which is the same lesson the union teaches.

Catching It Before the Walls Close

The best time to find a weeping union is before the tub is enclosed, and that is what the required one-hour fill test is for. The installer fills the tub to 3 inches above the highest jet, or to the bottom of the grab bar on a tub with no jets, lets the water stand for 30 minutes while inspecting around and under the tub, then runs every electrical component on its rated 3-prong cord in separate outlets for another 30 minutes and inspects all unions again while the pumps move water. Ella strongly suggests doing this outside, before the tub is carried in, so that a union that shifted in shipping is re-seated while every joint is still easy to reach. The full procedure is in The pre-installation water test: catch leaks before your walls are finished, and a shorter explanation of what the test is and why it is required is in What Is the Pre-Installation Water Test on a Walk-In Tub?. The test flows straight into warranty activation, where your installer confirms watertight connections with the pumps running after a 20 minute fill, so ask your installer to confirm both were done before the access panel goes on for the last time.

Related Guides

• How to Reseal a Leaking Hydro Pump Intake on a Walk-In Tub
• Pump or Massage System Not Working: Connections, Relay Switch, and What to Check First
• Water in the Lines or the Crate of a New Walk-In Tub Is Normal: Every Tub Is Water-Tested Before It Ships

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