The Most Common Methods to Heat a Spa
The 2 major methods to heat the water is either a jet pump that pushes water pass the heater (high flow) or a low pressure circulation pump pushing the water pass a low flow heater.
High Flow pumps ususally are on only to heat the water and filter cycle. Low Flow pumps typically operate 24/7 or close to it.
Tests have shown that the cost of operation for both is about the same. Advantage of High Flow is not seeing the hot tub running all the time. Advantage of Low Flow is both the water is being filtered and sanitizing constantly.
Using a High Flow pump to heat the water is the most common.
As shown the water is sucked through the filter, through the pump, pushed through the heater, into the plumbing, and out 1 or many jet assemblies.
The most popular heating cycle is filter to small circ pump, through heater (can be many styles) and out some jet assembly port.
This setup uses a standard size circ pump with LOW horsepower. About 1/16 hp.
Water is pulled through filter, through wetend, through 15" heater, and out a jet assembly.
