Variable Frequency Well Pump Upgrade

[UncleDave]

The short - awesome upgrade from a single stage 40/60Lb pressure switch and an 80 gallon pressure tank to a Grundfos SQ series and tiny tank.
It gives the home city level performance.

The prior owner flat out lied to me about what was in the ground and when it went in.
This stuff was put in during the Bush 1 administration. Props to the stuff for making it to 35 years and be retired while working.

 

[oilboy123]

I did not know there was a variable frequency pump. I'm running on the original pump/tank for our well. This is from 1993. So I'm due for a new pump/tank. I have a triple Big Blue filtration I need to do the filters on as well. I assume the variable frequency is like an inverter heat pump?

 

[UncleDave]

I did not know there was a variable frequency pump. I'm running on the original pump/tank for our well. This is from 1993. So I'm due for a new pump/tank. I have a triple Big Blue filtration I need to do the filters on as well. I assume the variable frequency is like an inverter heat pump?

Similar. The pump can ramp from 65% to 100%.

It's a soft start pump so it takes 3 seconds to ramp from a stop so running it off a generator is easier.

Ive got a whole new filtration system to put in as well on stop 2 here.

 

[dnewton3]

What was the cost of the new pump? Does it need a separate driver?

 

[97K15004WD]

Better make sure your generator can handle the harmonics from the VFD. 3rd and 5th order harmonics will kill a generator at the worst possible time. Check with your genset manufacturer on what they recommend.

I do power quality analysis and this is one of the things I look for.

 

[doitmyself]

Lots of options with wells. With my workplace 4 inch irrigation well installed 12 years ago, we tried a cycle stop valve* system and it did not work out too well. Not blaming the cycle stop valve(there were installation errors). Every system and situation has pros/cons. When our steel drop pipe corroded prematurely last year, we replaced the submersed pump, went with plastic drop pipe (requires "twist stop" brackets), and variable frequency drive. Time will tell how this works out, but I like the system so far.

* https://cyclestopvalves.com/?srsltid=AfmBOoowJvILaqzYMbpbsjkieCou5xK8EaOgWUiSMaCjy0CAyofGjmSu Just another option to consider in-between the large pressure tank systems and VFD systems.

 

[DCDG]

can the vfd function be disabled and run as a standard pump as well? in the above mentioned situation running off generator power

 

[melk]

Timely topic for me as I’ll soon be closing on some land that has a well, first time for me dealing with such.

It was drilled 10 years ago but never hooked up, sitting capped. Somewhat deep, at least for the local area, at 350’ give or take, but has fantastic yield.

 

[97K15004WD]

can the vfd function be disabled and run as a standard pump as well? in the above mentioned situation running off generator power

Only if you have a VFD Bypass panel installed.

 

[97K15004WD]

This is an example of one I did last week. The VFD is not controlled on the output side and is generating over 20% THD on the driven motor. The motor is overheating and on the edge of failure. Lifespan is cut in half due to heat rise in the windings.

In this particular case, the input side was not the issue; BUT a VFD will input harmonics on the input side and this will backfeed to the genset typically causing heating of the windings and interference with other equipment on the same feed.

Best to check with the genset manufacturer and make sure there will be no issues.

 

[97K15004WD]

There is a lot of information on the web regarding harmonics and VFDs. I would recommend looking into that BEFORE adding one to your home system. A soft-start, on the other hand, switches over to a contactor once full speed is achieved and has none of the side effects of a VFD.

Another issue with VFDs is on long motor wires. Anything longer than 75 to 100 feet typically needs an output filter to control reflected voltage and mitigate motor insulation damage.

Unless you specifically need the benefits of a controlled ramp for acceleration and deceleration, the possible consequences to your home systems isn't worth it IMO - to each their own, however.

 

[Rob_Roy]

* https://cyclestopvalves.com/?srsltid=AfmBOoowJvILaqzYMbpbsjkieCou5xK8EaOgWUiSMaCjy0CAyofGjmSu Just another option to consider in-between the large pressure tank systems and VFD systems.

I installed a Cycle Stop Valve in my house and in my parents house as well. So far it is working very well in both homes. I think it is a great option for anyone looking for more consistent water pressure, especially if you want to keep using an existing pump that is not compatible with a VFD.

 

[UncleDave]

What was the cost of the new pump? Does it need a separate driver?

It was something like 2K with the controller.
This version requires the controller from what I can derive.

 

[UncleDave]

Better make sure your generator can handle the harmonics from the VFD. 3rd and 5th order harmonics will kill a generator at the worst possible time. Check with your genset manufacturer on what they recommend.

I do power quality analysis and this is one of the things I look for.

Not at all worried about it. My exact combo has been replicated at two other employees houses.

Kohler 20K / Grundfos SQE

The pump has a wider range of operable voltage than any other well pump I could find.

Which pump and controller were you working with when you measured the THD?

 

[UncleDave]

I installed a Cycle Stop Valve in my house and in my parents house as well. So far it is working very well in both homes. I think it is a great option for anyone looking for more consistent water pressure, especially if you want to keep using an existing pump that is not compatible with a VFD.

I like the cycle stop valve and employ one elsewhere in my irrigation system.

It doesn't give me soft start, the wider voltage range, nor the unlimited pump starts.

They are also subjected to impact from sand, requiring a more expensive version if you want protection from sticking.

Ill often trickle my well to the irrigation buffer tank off season and this results in frequent starting and stopping hence making unlimited starts desirable.