You switch to spa mode, sit down, and the jets feel like someone breathing on your back. Or two jets are pumping and the rest are doing nothing. With spa jets not working on a spa that’s attached to the pool, the jets themselves are rarely the problem. It’s what’s feeding them, and that’s a lot of what we look at on pads around pool service calls in Agoura Hills and the rest of the Conejo Valley.

A combo spa doesn’t have its own little system. It borrows the pool’s pump, filter and plumbing, and a pair of valves decides whether that water goes to the pool or to the spa. That sharing is why the usual causes are different from a standalone spa.

Where combo spa jets get their push

On most combos, the main pool pump runs the spa jets. Water comes out of the spa, goes through the pump, filter and heater, and gets shoved back into the spa through the jet fittings. Each jet is a venturi: water squeezes through a nozzle, and that pulls air in from a line that runs to an air control on the deck.

Some spas have a separate jet pump, sometimes called a booster, that only runs in spa mode. Some also have an air blower, which is a different thing. The blower makes bubbles through the floor or seat. It doesn’t make the jets stronger.

Knowing which setup you have saves a lot of guessing. If there’s one pump on the pad, the jets depend on the pool pump. If there are two and one only runs when the spa is on, that second pump is your jet pump.

Check the pump speed before anything else

This one is common. Variable speed pumps are built to run slow for filtering, and the California Energy Commission requires replacement pool pump motors of 0.5 horsepower and up, made since July 19, 2021, to be variable speed. Slow is great for the electric bill. It’s terrible for spa jets.

Pentair’s IntelliFloXF manual lists a range of 450 to 3450 RPM, with Speed 1 at 750 RPM as the default filtration speed. The same manual says “the higher speeds can be used for spa jets, water features, and priming.”

So if the spa mode on your automation doesn’t also tell the pump to speed up, you’re running the spa on filter speed. The jets will move water. They won’t feel like anything. The fix is usually a setting, not a part.

Valves that only go partway into spa mode

When you hit spa mode, valve actuators turn the suction and return valves so the pump pulls from the spa and pushes back into the spa. Jandy’s JVA actuators run on 24 volts and stop where internal cams tell them to. If a cam slips or the valve diverter inside breaks, the motor can turn while the valve doesn’t, which Jandy lists in its own troubleshooting chart.

A return valve that stops halfway sends half your jet water into the pool. You’ll see it: the pool returns are still pushing hard while the spa jets are weak. Jandy’s manual also says that on a combo, a valve problem shows up as “spa draining or overflowing,” so a spa level that drops while it runs points the same direction.

Actuators and diverters are covered in our post on pool equipment that breaks most often. They’re a common repair and not an expensive one.

The air controls on the deck

If the jets are pushing water but there’s no fizz in them, look for the air controls. They’re usually small knobs or caps on the spa coping or deck. Turned closed, the venturi can’t pull air, and the jets feel flat even when the water flow is fine.

They get bumped closed, kicked by a dog, or turned by a guest who didn’t know what they were. Open them all the way and run the spa for a minute. If that fixed it, nothing was broken. That happens more than people admit.

Clogs in the basket and the filter

Everything going to the jets passes through the pump basket and the filter first. Pentair’s IntelliFloXF manual lists a dirty filter or plugged pump basket under “inadequate circulation,” and in fall that’s oak leaves, sycamore leaves and whatever the Santa Anas blew in.

Pentair’s Clean and Clear Plus support page says it’s time to clean the filter when the gauge reads 10 PSI over its starting pressure. If you don’t know the starting pressure, that’s a good number to write on the filter with a marker after the next cleaning. Our post on the signs a pool filter is going bad covers the rest.

Air in the suction line

If the pump basket lid shows a lot of bubbles, or the jets surge and sputter, air is getting into the suction side. Pentair’s manual points at the suction piping and the valve glands, and at a water level low enough that the skimmer is pulling air.

On a combo, check the spa level too. When the spa suction is open and the level drops below the jets or the suction fitting, the pump starts gulping air. A pump lid O-ring that’s dry or cracked does the same thing. Grinding, screaming or a leaking seal is a different conversation, and that’s in our pool pump repair post.

When it’s just one or two jets

If most jets are strong and a couple are weak, the pad is probably fine. Look at the fittings themselves. A lot of spa jets have an adjustable eyeball or a rotating face, and some can be turned to restrict flow. Twist the weak one to see if it opens up.

Debris also gets stuck behind the nozzle: leaves, a bit of pipe glue, pieces of an old jet insert. The fix varies with the fitting. Some unscrew from the face, some need a tool, and some old gunite jets need more work than they look like they do.

Weak jets by symptom

Don’t ignore a loose or missing suction cover

Spas have suction outlets near the floor, and the covers on them are a safety part. If one is cracked, loose or missing, don’t use the spa until it’s fixed. Spa suction is strong and the space is small. Our post on what counts as a pool emergency explains why this one is on the list.

Asked at the pad, every week

Why are my spa jets not working after the pool was serviced? Usually a valve got left in the wrong position or a pump setting changed. Check that the actuators are switched on and that spa mode still calls for the higher pump speed.

Can I just run the pump at full speed all the time? You can, but you’d be throwing away the reason variable speed pumps save money. Program spa mode for high speed and let the pool filter at low speed.

Are weak jets a sign I need a bigger pump? Rarely. If the jets used to be strong and got weak, something changed. A bigger pump doesn’t fix a closed valve or a clogged basket.

Does the blower make the jets stronger? No. The blower adds bubbles through separate openings. The jets get their push from the pump.

Spa jets not working after all that?

If you’ve checked the speed, the valves, the air controls and the filter and nothing changed, take a short video of the pad while someone switches to spa mode. We want to hear the pump and see the actuators turn. Send it through our contact page, along with the brand of your pump and automation.

We work on Pentair, Jandy, Zodiac, Hayward and Sta-Rite equipment, including the automation that runs your pool repairs and equipment upgrades. Or call (805) 586-2055.