troubleshooting a hot tub/spa that won't heat up
Deltaray,

I have a Hotsprings Grandee 220V. I've experienced a few power related issues. Here are my thoughts:


Makse sure the thermostat is set higher than 70 degrees. Should be a no brainer but you never know.
Make sure the breaker for the heater is on. Mine has 2 breakers in the sub panel, one for the heater and one for the pumps and electronics.
Try resetting everything. Turn off the breakers, let it site for a minute, turn the breakers back on.
On mine the cover for the control box is easy to open with a screwdriver. Turn off the breakers and open the control box. Examine the wires that go to the heater. Make sure they are attached. 
Mine also has a fuse or two on in the control box. Look to see if they are blown.
The heaters do not last forever. They are pretty simple to replace, especially if you already have experience replacing the circulation pump.
If you are comfortable with electricity it is easy to see if the heater is getting power at the control box. Use a volt meter to check for voltage.
If the circulation pump was not working, the heater could have overheated. Look for a reset button, or if you know the heater is getting power, replace the heater.


When the heater is working you should feel hot water coming out of the drain vent. Your electric meter should also be spinning pretty fast. My Grandee takes a few hours to heat up, but you should feel the hot water almost immediately.

What year/model do you have? 110V or 220V?