Actuator not turning

Check the switch on the actuator

This is the one that catches most people, so do it first. On the actuator there is a small switch with three positions: on 1, on 2, and a deactivated position. Deactivated does exactly what it sounds like — the actuator stops accepting commands and won't move at all, no matter what the controller asks of it. If your switch is sitting there, you've found your problem: move it to one of the two on positions.

If it's already on 1 or on 2, it may still be on the wrong one. Which position is correct depends entirely on how your system was plumbed, so there is no universal answer and no "right" setting we can tell you over the internet. What is the same on every system is the principle: in one position the valve sends water to the roof when the controller calls for heat, and in the other it does precisely the opposite. Flipped the wrong way, your system turns off exactly when it should be heating, and on when it shouldn't.

To tell which way yours should be: set the controller to call for heat and watch the valve for a few minutes. Give it a real reason to run: set the set-point at least 5°F above the pool's current temperature, and do the test on a sunny afternoon when the air outside is also at least 5°F warmer than the pool — a controller with only a degree or two to work with may correctly decide there's nothing to gain and never call at all. Then set the set-point below the pool temperature and watch it again. If the valve moves but does the opposite of what it's being asked, flip the switch to the other on position and repeat the test.

Give it time. Actuators are slow by design — they take a good while to travel — and most controllers wait before acting on a change. Flipping the switch rapidly back and forth tells you nothing except that it's still moving.

Make sure something is actually asking it to turn

An actuator that never moves may be behaving perfectly, because nothing is telling it to. At the control box, check three things: that it's powered up and switched on, that it's in its automatic mode rather than off or manual, and that the set-point is at least 5°F above the pool's current temperature. A set-point below the pool will never call for heat at all, and one sitting a degree or two above it has almost nothing to ask for.

Check the pump as well — not because it stops the valve. On most systems the actuator will turn whether the pump is running or not, so a still valve is rarely the pump's fault. But a valve turned to the roof with no water moving through it heats nothing, so if the pump isn't running during the warm part of the day, that's the reason the pool is cold even when everything else is behaving.

One more: if the roof sensor has failed, the controller may believe the roof is cold and never call for heat at all. A sensor error light on the display, or a roof temperature that can't possibly be true, points there instead — that's its own guide, and it's on the way.

Look at the wire

Follow the actuator's cable back toward the controller as far as you can see it. Check that nothing has been pulled loose at either end, and look along its length for damage — rodents chew them, years of sun crack the jacket, and a cable can get pinched by an equipment-pad lid or caught during landscaping. A connection that's simply worked loose is common, and it costs nothing to push back into place.

Stop at the enclosure. Don't open the controller up and don't start testing voltages. That's electrical work, and it's ours.

If none of that did it

Then the actuator itself has most likely failed — the motor or the gears inside it. That's a replacement rather than a repair, and it's one of the more straightforward and less expensive jobs on the system, so it's worth a call rather than a project.

You can keep swimming in the meantime. Setting the switch to the deactivated position leaves the valve where it stands, so ring us and we'll tell you which way to leave yours for your particular plumbing before we get out there.