How to Troubleshoot a Chattering Contactor


Hot tubs produce a lot sound. They bubble, blow, whir, and make all manner of (mostly) pleasant ambient noises. Unfortunately, when you have malfunctioning equipment, those noises can become unsettling. If you’re hearing a consistent click or chattering noise, there’s a good chance you have a contactor that is switching on and off continuously. That on and off switch makes a clicking sound and is termed a “chattering contactor.” Electrical contactors are used in most mechanical spa systems as part of the heater circuit. If you have a chattering contactor, here are some steps to help find and resolve the issue.

WARNING: This article is written for people who have a basic knowledge of electrical work. DO NOT work on your hot tub if you are not comfortable working around water and electricity (which can be a dangerous combination). If you are incapable of performing the repair yourself, contact a hot tub professional or licensed electrician.

The wiring described in the article is meant to represent a traditional spa pack. Your unit may vary from the components described below. Move forward at your own risk.

  1. Test the voltage at the coil on the contactor itself. If you have voltage on par with your unit, continue on to the next step. If you DO NOT have proper voltage (low reading), move on to step 5.

  2. Test the pressure switch. If it is faulty or sensitive, replace it. If this is not the problem, proceed to step 3.

  3. Examine the thermostat. See if it is releasing properly when the spa reaches the pre-programmed temperature. If it is not releasing, or “hanging on,” replace the thermostat. Proceed to step 4 if this is not the problem.

  4. Check all the other components on the coil side and look for any loose connections. If all components and connections seem to be properly tightened and operational, the contactor is definitely the problem and needs replacement.

  5. If your voltage test in step 1 determined a LOW voltage problem, test the main panel for voltage. If you have a low voltage reading there, call your electrical utility provider and see if it is something they can examine and rectify.

  6. If the voltage is fine at the main panel, test for low voltage at your spa pack. If you’re receiving a low voltage reading, check for feed wire that is too small for the pack or burn marks along the wife. If the voltage is fine at the spa pack, test for voltage through the coil circuit. The problem may lie there.

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