RFI from Grundfos Well Pump Forum Help
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RFI from Grundfos Well Pump Reply
by KF6MYE on February 20, 2007 Mail this to a friend!
I have a GRUNDFOS model CU301 Water Well Pump system that makes RF noise on on a good portion of the HF bands. I contacted the company and they said they could do nothing and said I should install a line filter. I purchased a 220V line filter and installed it in the 220V line as close to the pump control as possible. It seemed to solve some of thge problem, but the noise is still there. The pump cotrol uses HF frequencies to control the speed of the pump. Was wonder if anyone had the same problem and fixed it?
RE: RFI from Grundfos Well Pump Reply
by KG4RUL on February 21, 2007 Mail this to a friend!
What is interesting about this unit is there is NO indication in the avialable, on-line documentation that it has passed UL testing or has been registered with the FCC! Does your equipment actually have labeling for either of these?
Dennis KG4RUL
RE: RFI from Grundfos Well Pump Reply
by AB5GU on March 6, 2007 Mail this to a friend!
You are going to see more and more of this problem. All of the A/C manufacturers are designing their new air conditioners and furnaces around this technology. The pump motor is a variable speed via variable frequency design. This is very different from the multi-speed motors you are used to. Normal motors run at 50 or 60 hz and change their speed by varying the number of poles (windings) engaged. This new style motor changes speed by changing the frequency of the input power. By changing the frequency, the running speed of the pump changes. The frequencies emmited are quite broad. They know that it is leaking signal too, refer to the multi pump instructions.You should use shielded wiring to a sepatate ground rod as stated in the manual. Also, PVC, CPVC, or PEX water piping close to the well and up to the house might help keep it from being transmitted into the house. I'd also put the wiring to the controller and between the controller and pump in EMT conduit, also tied into the ground rod.
I hope this helps,
Marty Haley AB5GU
Master Plumber, AA Air Conditioning Licensee, Water Well Operator License Class C
RE: RFI from Grundfos Well Pump Reply
by KF4MM on July 3, 2007 Mail this to a friend!
I just found this thread in a search for my own Forum that is about Water Well Pumps etc. The new variable speed motors are changing the frequency of the motors to vary the speed electronically and RFI isn't the only problem I have heard of with these motors.
Personally I have no use for the new technology as it is about 3 times the expense of a standard motor and about 1/3 as dependable. You can get the same result with a standard motor a small bladder tank and a Cycle Stop Valve that costs under $70.00.
I've been in the well business all my life and you will never find one of these units in my well.
bob...
RE: RFI from Grundfos Well Pump Reply
by K7CF on December 3, 2007 Mail this to a friend!
Had the same problem, same model as yours. Since there was no fix, removing the CU301 and putting in a larger tank, and having a sensor put in like in the good ol days is supposedly going to fix it. The pump is an SQE and according to the manufacturer, the pump and the CU301 send packets back and forth to each other at 130 KHZ or so, continuously as to whether there is turn on of the pump required. The CU301 and the SQE pump both have transmitters in them.
The Groundfos engineers say, eliminating the CU301 control box will make the problem go away. Will have to see.
All those folks who are putting out "transceivers" that harmonically interfere with Commercial AM radio and others from Pumps, furnaces, and others, are like General Motors did with the Corvair car, where they said the cost to fix is less than the cost to litigage as long as we allow them to get away with it, they will.
