Well pump usage with open loop geo - perspectives?

[dryhero]

Topic straddles pump and geo topics. My 3 ton R22 ClimateMaster geothermal is losing refrigerant, HVAC guys say replace. When contemplating a (modulating compressor) WaterFurnace 7 series, 2 different company's sales reps warned against high electrical cost due to excessive pump usage. They said the WF7 uses 5 GPM regardless of speed, runs more often, and on an open loop electrical usage will offset high efficiency savings of WF7. May be accurate, but I'm not 100% convinced.

I have Valveman's cycle stop valve and 2 119 gal pressure tanks. CSV is everything advertised, best advice rec'd in years!

QUESTION: Are salesmen using bad science?

- Most geothermal manufacturers spec 2-3 gal per ton (3T = 6 - 9 GMP)
- CSV back pressure should throttle well pump amperage a bit?
- CSV will probably use more total electricity than w/o?

Thanks for your perspectives!

 

[Valveman]

After 17 years my 3 ton open loop Comfort Air heat pump started losing refrigerant. It only needed 4 GPM from the well pump and had no "modulating" anything. Couldn't find a replacement that didn't have a "modulating compressor and/or fan". Have had so many people over the years tell me of all the problems with the "modulating" stuff that I did not want to go that route. Decided to switch out the heat pump for a standard HVAC unit, which I could get without any "variable speed (modulating) stuff". First winter my electric bills are at least a hundred bucks a month higher. Guessing cooling in summer will be even worse. Already don't like the noise of the compressor outside, which the heat pump did not have.

As far as pumping cost for a heat pump, many people have told me it doesn't matter how efficient the heat pump is if they cycle the well pump to death every couple years. Cost of replacing the well pump far exceeds any benefit of the heat pump. Adding a Cycle Stop Valve can increase the electric bill for low flow rates the same way a variable speed well pump would. But the CSV can make a pump last decades, which can easily outweigh a little extra energy cost.

With the 60 gallons stored in two 119 gallon pressure tanks the well pump won't come on until the 5 GPM heat pump has been running for 12 minutes. If the heat pump cycles are less that 12 minutes, the efficiency of the CSV won't even come into play. With a smaller tank or longer than 12 minute heat pump cycles the size of the well pump determines how much energy is being lost through the CSV. If it is a 25 GPM well pump it will be less efficient at 5 GPM than a lower horsepower 10 GPM well pump. My feeling is that as long as you can keep the well pump from cycling itself to death it would have to be very inefficient to keep a heat pump from saving energy.

I liked my heat pump. But it was old school, nothing variable speed or modulating to give problems. I have heard a lot of people tell me those variable speed compressors save a LOT of energy because they are broken and not running half the time anyway.

 

[Sponsor]

 

[dryhero]

I feel your pain, no country for old men! As always, thanks Cary!