14’ round pool 1.25”inlet line I connected 1.5” line to increase flow as I have a Raypak 18kw heater after the filter but it requires flow rate greater than 15 gallons per minute. With this setup I am only getting 13 gpm. How do I increase my flow rate? I have an intel 635T filter pump that supposedly gives 19 bpm flow rate.
There are two ways to increase flow rate. You can either boost the pump power (voltage) or increase the inlet diameter. If you want to increase flow rate without increasing the inlet diameter, then you need to increase pool horsepower. If you want to increase flow rate, you can do it in two ways: you can calculate water flow rate and simply increase the pump horsepower, or you can increase inlet diameter on your filter (I am not sure about your pump). If you increase the pump horsepower, you need to make sure the heater can handle the extra heat generated, or the water heater will burn out.