Description
This genuine Balboa M7 Heater Temperature Sensor features a 24" wire length and arrives complete with wire, connector, and screw-down cap included. The tube and tube-side mounting bracket are NOT included, as existing mounts can typically be reused from your original installation. A faulty sensor commonly triggers an SN error code on Balboa M7 control systems.
Question: Why does my spa display an OH error code when the water temperature isn't actually hot?
Without additional details, here's what you should understand: If your water reads cooler than 110°F, one of two issues exists. Your M7 system utilizes dual sensors (like this part) installed at both ends of the heater tube. When the circulation pump malfunctions, the heater still activates and monitors the temperature differential between both sensors to verify proper water flow. The control system cannot directly detect water presence, so it uses this temperature comparison method rather than the pressure switches found in older designs. Once the heater fires, no temperature increase signals a circulation problem, causing the system to pause briefly before reattempting. Repeated firing cycles without flow cause tube water temperature to climb, eventually triggering an OH code and automatic shutdown until manually reset. The key point: If your pump operates inconsistently, your problem stems from pump issues, not sensor failure, since the sensors correctly detected high temperature and displayed the appropriate code. Investigation should focus on pump performance. Additionally, excessive filter cycle settings can cause OH codes, particularly in warm outdoor conditions or indoor installations. Never exceed F2 filter cycle settings during high ambient temperatures.
