Sundance Spas, Heater Flow Switch, 6560-852 Sundance Spas Flow Switch Original Sundance Spa Parts Part #6560-852 Used on the following Sundance Spa Models: Sundance 800/850 Models using the 6500-301 Bypass Heater, up to 5/1999 780 Dover, 2008+ Metro and Solo, 2007 Caprio, Metro and Solo, 2006 850E and 780 Lagunas Models, 2005 All Portofino Models, 2000-2004