Hi, hoping someone can help me. I'm having a problem with my HotSprings Pulse. No control panel lights, not indicator lights. Took IQ2020 cover off and three lights are rapidly flashing in sync (red Power On, a larger green LED on a sub-board, and a red LED labeled D21). I've replaced both thermistors... no change. Is there anything else the IQ2020 checks upon startup? Could this be a pressure switch problem? Note: Occasionally it just begins working, but then faults out with the same symptoms.