Agreed, geoexchange censors based on who pays or might pay - not a good source of unbiased information. On the other hand, my opinion is that Valveman should always disclose his commercial interest when discussing his CSV - without being prompted.

Posted By jonr on 06 Jul 2016 12:42 PM
Agreed, geoexchange censors based on who pays or might pay - not a good source of unbiased information. On the other hand, my opinion is that Valveman should always disclose his commercial interest when discussing his CSV - without being prompted.

I don't understand why people cannot see the name "Valveman" as disclosure? I guess I need to start using Cycle Stop Valveman instead. :) And I always put my web page as a signature if possible, but I don't want it misinterpreted as advertising. Cyclestopvalves.com

Nathan, you inspired my project and i just installed a PID20 as well - so thank YOU. i was looking for this information for a long time and your data convinced to do the same. I had the CSV setup, however, it did not drop amp at all - barely any!!!. I have a 5 ton multistage geothermal which requires variable water flow rates ranging from 5 to 18 gpm of course at the lowest possible PSI. I have 3/4 HP pump and it was drawing 7 AMPs now i'm down to 1.9 amps (significant improvement). The CSV was great at maintaining the pressure, but not lowering power usage by much. I will also be using the second setpoint for irrigation.

Have you connected it to grap telemetry data ? if so how?

Some brands of pumps will not drop amps at all when restricted, some will drop by 50%. The CSV cannot reduce the output pressure of the pump, it only reduce the pressure to the system. Using a VFD to reduce the pressure to the heat pump from 50 PSI to 20 PSI will reduce the amperage even more. But 20 PSI is not enough to supply the house or irrigation if you need to do these things at the same time the heat pump is running. I use a 1/3HP pump to supply 20 PSI to the heat pump, and it only uses 2.2 amps. This is not enough difference to justify the use of a VFD. Then I have an additional 1/2HP booster pump that supplies the added pressure needed for the house and/or irrigation. In this way I can be running the heat pump at 20 PSI as well as feed the booster pump 20 PSI. Then the booster increases the 20 PSI to 50 PSI only for the water that goes to the house. This way the additional pump and additional power is only used for the short times per day when the house or irrigation needs water. When you start out with an over sized pump, a VFD can reduce the power consumption considerably. But it is still wasting energy compared to a pump that is sized to correctly match the heat pump load. I would guess that a correctly sized pump, running at full speed and at its best energy point would save 20% to 40% more than the larger pump with the VFD. But the convenience of being able to use the pump for other uses maybe worth a little less efficiency. Anyway I am glad you got the energy consumption reduced, I just hope the VFD system last long enough for you to receive a ROI.

I cannot figure out how to show a curve for this 3/4HP that will have an amp drop of over 50%.

Go to this link and look up a curve for a 16S07-8.
http://product-selection.grundfos.com/product-detail.catalogue.product%20families.html?from_suid=1475672752195031064212334120156&pumpsystemid=150460073&qcid=150460100

I wonder how many well pump power measurements account for power factor. Amps don't actually matter (you aren't charged for them) and you can't get watts by multiplying amps times 240V. OTOH, a power/energy meter will provide accurate comparisons.

For single phase I think you can if you multiply amps X volts X the power factor. But yes the power factor makes a difference. You can even get a Cap Start Cap Run (CSCR) control box for those little submersibles, that way they have a running capacitor. Running at less than full load can decrease the power factor, so a start cap should help.

Sorry I meant a RUN cap should help.

For single phase I think you can if you multiply amps X volts X the power factor.

I agree, but the power factor changes with load and things like VFDs and CSVs change the load. Luckily, power/energy meters will do the measurement right and they are only $15 on ebay.

I would like to see an example of this $15 power/energy meter....I am looking for a good clamp on amp meter and they are over a hundred.

Thanks.

This VFD (PID20) has dual setpoints for pressure, so i'm setting 15 PSI for geo and 50 PSI for irrigation and no need for a booster pump. So far i'm getting reading from 250 W to 400 W (1.6 to 1.9 amps) vs 1600W and 7 amps. HUGE difference. at this rate, my payback is less than 2 years and this is being conservative.

Your numbers suggest a simple multiplication by 230V (PF=1) but 7A into a 3/4HP pump suggests a very different PF. For example, a 3/4HP pump drawing 6.8A at full load should be about 940 watts and not more than 1200W. What are you using to measure before and after watts?

This should be good enough for comparisons.

Those VFD's usually have a screen that reads in watts. And they claim to run the pump with a power factor at unity or 1. But the meter doesn't see that as it is only charging the capacitors in the DC buss on the other side of the VFD. Being able to reduce the pressure to 15 PSI is really what is saving the energy and 250 to 400 watts is pretty good. Curves show a pump sized for exactly 15 GPM at 15 PSI would use a little less than 1/3HP, which should be 200-240 watts at best. Now it is all about how long the pump and controls will last.

I used an amp meter before and after. Yes, I was using a simple multiplications. I used the same amp meter in both cases!!! The display can show amps or Watts.

keep in mind that my geo flow demand changes, so when its running at full speed, i do expect to see different and higher numbers. However, my geo requires lower flows 80% of the time. that is where i will see my biggest saving. Last year the geo ran for 4000 hours!!!! so for simplicity, if that is 3200 hours at 400 W vs 1600W, that should be huge savings.

I suspect that correct figures for your situation are more like 940W down to 250-400W. Still a nice savings (maybe $250/year?).

where did you get the 940 w from? average?

A guestimate from Franklin's figures (click here) and knowing that a CSV reduces load (which lowers PF). Your before measurement had a low power factor and your after measurement probably had a power factor close to 1. Without knowing power factor, you cannot convert motor amps into watts.

Got you - thanks.

The other great advantage is NOISE level is gone. Before, i would just have to open the basement door to know that the pump is running. Now, not even close!!!