This does not allow a 240 volt heater to operate, but will allow the 115 volt pump to run. Heater element dry well leaked on the electrical components and caused the GFCI to trip. The transformer on the main circuit board quit working. There are many more reasons, I wish I had kept a log. If anything stops your vented spa in the winter, you have to get help to it right away, When the cold air rushes in to the vulnerable equipment and pipes, it makes a terrible mess out of your equipment.
Water expands as it freezes.
It breaks your spa. To my thinking, having a GFCI Breaker on a spa is a wonderful idea. If it saves one life it is worth all of the trouble. Now it is required by law to install one on all new spas, and I recommend having one installed on all spas in the breaker panel. If you notice, there are 16 new reasons for the spa to shut off.