10/22/2026
A spa that heated fast in August can feel painfully slow on a cool Ventura County night. The heater is not always the problem.
π’ A heavy spa spillover sends warm water into the colder pool.
π’ A valve actuator that stops short can mix pool water into the spa loop.
π’ A dirty cartridge filter or low variable-speed setting can make the heater cycle off on flow.
If the heater fires and the spa return is hot, the issue is often flow or valves, not a dead heater. Take a quick video of the valves switching and a photo of the filter pressure before assuming you need a new heater.