My 2005 Hot Springs Envoy spa will not heat.
- Heater light is on.
- On the circuit board:
- Lim Ok has green light,
- HTR On has Red light.
- Circulation pump is running.
- Heater Relay Board and wires going to heater:
- Black wire reads 17V,
- White 121V,
- Red 121V,
- combo or Red & White 214V.
I'm not sure why the Black would read 17V. Is that normal? Do you think I need a new relay board or heater?
Heater placard says 240V 4KW SSE-00-0H-0f was red tape