He is correct on the heater, not on the salt. Most salt systems require 20-30GPM. I can get that down to about 1200RPM. I run at 1400 to protect from a dirty filter.
Gas heaters have different requirements. They are also a bit restrictive. The Raypak for example needs 20GPM for the 206, 25GPM for the 266, 35GPM for the 336, and 40GPM for the 300/406. When I run my heater, I need to run at 2200 to get 35 GPM.
I ran the numbers on the two VSP I recommended, the MaxFlo in one of the quotes, the Calimar, and a two speed super pump.
It is clear that the VSP is a clear winner over any single or two speed, the payback is obvious...get a VSP.
When it comes to the priciness of the higher HP VSP, two things are true:
- The Calimar (or similar Waterway Defender [which I don't have pump curves for...) being at lower price points is the winner. At $519, after 5 years, you can buy another pump and still be cheaper than any of the Hayward VSPs.
- There is savings in the larger VSP, but the payback period, for the pricey 3HP can be significant. The payback on the 950 is 7 years.
Net net:
Get a VSP, even if is smaller unit.
Gas heaters, and heat pumps are going to be restrictive and require higher GPM than the salt cell. Depending on how you use your heater, the payback calculation will change.
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