Hi memse
I am so sorry that you have been taken in by the Variable Speed Pump (VFD) scam. The VFD is designed to separate the consumer from as much of their money as possible. The way the pump manufacturer is looking at this is that they already have more of your money than they would have gotten with a conventional pump system in 30 years time. So they really don’t care that you are mad, or if you switch brands of pumps.
With a booster pump that produces such low pressure, you really don’t need anything to vary the flow rate for the different size zones. The VFD would only allow the pump to be slowed down by 13% (almost no variation), and still produce the 40 PSI you need. And a pump that only builds a maximum of 52 PSI, really doesn’t need a CSV either.
Requiring a three phase motor to work with the VFD, is one way they try to lock you into continually repairing this system instead of being able to use something different, as you could if you had a single phase motor.
I hate to recommend any Goulds pump since they already have a lot of your money. But they have a pump model GT15 that I find on the Internet for about $350 that would work very well. But if you want to stay away from "that" company, you could use a Sta-Rite model DS3HF which I find for about the same $350. Of course Sta-Rite does the same thing with VFD’s as well, just that they haven’t had the chance to fleece you yet.
Since these pumps are single phase, all you need is a $25 pressure switch to control them. Set the pressure switch at 32/52. Then you will have 37 GPM at 40 PSI, the same as with the pump you have now. You can also run as little as about 7 GPM without the pump shutting off (cycling on and off). But you will need a little 20 gallon size pressure tank, which I can find on the Internet for about $120.
So I am guessing you spent $1500 on the original installation, and I added up another $2115 that you have spent since then. This is after you got one controller warranted at no charge. This adds up to about $3615 that you have spent so far.
The pump I am recommending will cost $350. A pressure switch and pressure tank will cost another $150. This is a total of $500 cost, for something that should last 30 years without maintenance. This makes it easy to see why pump manufacturers are pushing Variable Speed Pumps the way they do.
To get you hooked they will tell you that the “soft start” from a VFD will make the pump last longer, and varying the speed saves energy. Both of these things are false, as you have discovered. You have basically just given them an extra $3100. Sorry! Let me know if you have more questions.
Cary
