If the pool warms up but the spa never gets hot, the heater may be working perfectly. It's heating the water it's being sent. On a pool and spa combination, motorized valves decide whether the pump draws from and returns to the pool or the spa, and the controller decides when the heater runs based on where it thinks those valves are. When a valve actuator doesn't turn, or the system isn't really in spa mode, the heater keeps warming the pool. Here's how to tell which it is, from Jandy, Pentair and Hayward's own manuals.
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A pool/spa valve actuator is the motor on top of a diverter valve that turns it between the pool and the spa when you switch modes. A combination system usually has one on the suction side and one on the return side, and both have to turn for spa mode to work.
The controllers are explicit about the order of events. Jandy's AquaLink RS manual says spa mode switches circulation from the pool to the spa after a delay of about thirty seconds while the valves turn, and that spa mode must be on to heat the spa. Hayward's ProLogic manual says the heater runs for the spa only when the pool/spa valves are in the "spa only" position, the filter pump is running and the spa is below its set temperature. Pentair's EasyTouch and Hayward's ProLogic both switch the filter pump off while the valves rotate, and Jandy's AquaLink has a Pump Lockout setting that decides whether the pump stops while they turn.
None of those controllers can see the valve itself. If an actuator doesn't actually turn, the system believes it's heating the spa while the water is still coming from, and going back to, the pool. The pool gets warmer; the spa doesn't. And if only one of the two valves turns, Jandy's actuator manual notes the symptom on a pool/spa combination is the spa draining or overflowing instead.
Before anyone touches a valve, check that the spa is actually being asked to heat. Each system keeps the spa's heat setting separate from the pool's, and each has a way to leave it off.
| System | Where the spa heat setting lives | The catch |
|---|---|---|
| Pentair EasyTouch | Menu > Heat > Spa Temp/Src: its own temperature (40–104°F) and heat source | A heat source of "Off" means no heating even though the pump and other circuits run |
| Hayward ProLogic | Settings menu > Spa Heater1 (Off, or 65–104°F) | In spa spillover mode the heater works to the pool setting, not the spa setting |
| Jandy AquaLink RS | The spa temperature, used only when SPA is on | Spa mode must be on to show the spa temperature or heat the spa |
| Pentair MasterTemp (heater on its own) | The POOL/SPA button on the heater | Separate set points, factory set at 78°F for pool and 100°F for spa; left in Pool mode, the spa only reaches pool temperature |
The spillover catch catches a lot of people. On ProLogic, spillover is the mode where spa water flows over into the pool; Hayward's manual ties the pool heater setting to the "pool only" and "spa spillover" positions, so a spa run in spillover heats to whatever the pool is set to. Switch to spa-only before deciding anything is broken.
Switch the system to spa mode and stand at the equipment pad. Give it the half-minute Jandy allows for the valves to rotate, then check:
Know which actuator is which before anyone starts swapping parts, because not every actuator on the pad is a pool/spa valve. Jandy's AquaLink lets the installer assign extra actuators to auxiliary buttons (on pool/spa combination models, a cleaner valve and a solar valve), and Pentair's EasyTouch can drive two auxiliary valves, A and B, with Valve A dedicated to the solar valve when solar heating is set up. An actuator that turns for a waterfall or the solar loop tells you nothing about the two that switch the spa.
If you need to move a valve without the controller, Jandy's power-on method is to flip the actuator's toggle switch to the opposite position, then return it afterwards. If you turn a valve by its handle, Jandy says to switch the filter pump off first.
The good news is that a stuck actuator is a small part of the system. Jandy designs its Pro Series actuator so that all major components, including the power cord, can be replaced without replacing the whole actuator: the motor, microswitches, gear train and shaft each have their own replacement kit. Setting the cams correctly matters too; Jandy warns that improper cam settings can dead-head the water flow. Jandy also lists three seals on its actuator to lubricate once a year. Pentair's EasyTouch pool/spa systems ship with two CVA-24T actuators, and IntelliCenter systems use IntelliValve.
If the settings are right and the valves are turning but the spa still won't heat, then it's the heater, and that's a different job: start with our guide to why a pool heater isn't heating or, on a Pentair heater showing a code, our MasterTemp error codes guide. For heater repairs see pool heater repair, and for actuators, panels and controller faults see pool automation repair.
Either the spa isn't being asked to heat, or the water isn't actually going to the spa. Check the spa's own heat setting first (it can be set to Off, and on Hayward ProLogic spillover mode uses the pool setting). If those are right, watch the valve actuators: if one doesn't turn in spa mode, the heater keeps warming pool water.
Switch modes and watch it. Jandy's manual separates three faults: the motor doesn't turn (no power, the toggle switch off, a failed motor or microswitch), the motor runs but the valve doesn't (a broken shaft or diverter, manual position, damaged gears), or it turns one way but not back (a microswitch, connection, relay or wire). Each points to a different part.
Usually because one of the two valves turned and the other didn't. Jandy's actuator manual lists a spa draining or overflowing as the pool/spa symptom of an actuator whose motor runs but whose valve doesn't turn, from a broken shaft or diverter, a damaged gear train or an actuator left in manual position.
On Hayward ProLogic, the heater works to the pool temperature setting in spa spillover mode and only uses the spa setting when the valves are in the spa-only position. Switch to spa-only to heat the spa to its own temperature.
Yes. Jandy's actuator can be moved with the power on by flipping its toggle switch to the opposite position and returning it afterwards. If you turn the valve by its handle instead, Jandy says to switch the filter pump off first.
Tell us which controller and heater you have and what the spa does when you switch modes. We'll check the settings, the valve actuators and the heater, and fix the part that's actually at fault. Licensed, insured, serving Cypress and Greater Houston.