What happens if I put a TS2021 pump , with the pulleys off a ts1511 pump .. and run it with a 13hp motor>> Will I get more GPM?? More Pressure ??? or will it just pump 3500 @4 gpm like the ts1511.. ??? I can buy the ts2021 cheaper thean the ts1511 thaqts why I am asking...
I would be more concerned with keeping the GPM close to what you had before, so that your burner can keep the water temp similar to what you're used to, knowing what the machine is used for.
The 2021 puts out 1.4 times as much water, gpm, at any given speed.