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Pumps, Wells, Tanks, Controls / Understanding Tank Sizing
« on: January 14, 2013, 12:09:32 PM »
Here are a few facts about my residential single pump setup designed and installed in 1979:
1. 300 foot deep 1 1/2 HP pump with a "pump saver" electronic device...as during the summer the water level is scary low...in fact, our lawn/garden irrigation is minimal year-round.
2. I have a 80-85 gallon tank about 15 years old with a 40-60 pressure switch. Lately the 38 lb setting is getting hard to maintain without more frequent checks. I have begun to research tank options and found you.
I’ve been reading extensively about your product on your site and a plumbing forum that mentions you (meaning you and your product have a good reputation).
I totally understand the idea that a larger pressure tank is not needed with CSV, even though I come from the “if bigger is better then biggest must be best” era. I keep wondering if “only” 4.4 gallons with a 1 gallon drawdown could be correct for me. Let’s assume the following usage (currently two adults in the home, but it’s a two adult+three kid home and will be again someday):
Activity CSV Cycles with CSV Cycles with proposed
1 gal drawdown 5 gal drawdown
20 "1.6" gallon toilet
flushes throughout
the day…32 gallons 20 0-10*
1 shower…35 gallons 1 1
1 washer load…35 gallons 1 1
1 dishwasher load…14 gallons 1 1
5 meal prep and dish
cleaning…4 gallons 5 0
1 steeping bath fill…40 gallons 1 1
2 toothbrush and
Listerine procedures…2 gallons 1 0
Totals 30 4-14
* It’s true that 0 cannot be the true number for toilet flushes, as some of those flushes would trigger a cycle, let’s say half would…that still brings my total to only 14.
OK, OK…that’s enough personal info about my flushing habits…I hope you get the idea.
Your statement is as follows: “A CSV with a 4.4 gallon size tank (1 gal draw down) will cause the pump to cycle about 40 times per day on the average house. Using the CSV with a 20 gallon tank (5 gallons of draw down) will cause the pump to cycle about 20 times per day on the average house. In most cases, this is not enough difference to justify the use of any larger than a 4.4 gallon tank. The way the CSV controls the pump system, there is really no justification in using a larger tank. Then if you consider the cost and space needed, there is even less justification for using a larger tank.”
Cary…you write a great story…what I suggest you consider is an addition of some language that explains your most important conclusion, which is:
“Using the CSV with a 20 gallon tank (5 gallons of draw down) will cause the pump to cycle about 20 times per day on the average house. In most cases, this is not enough difference to justify the use of any larger than a 4.4 gallon tank.”
To me, it sure looks like it’s enough to justify a larger tank! Cutting the cycles from 40 to 20 is great, I’d say. You should explain why it’s not great, if that’s what you believe. If you suggest on the one hand that cycles are a pump-killer, then getting them down to the very minimum seems a logical goal…you must know something you are not saying…you must.
And speaking of justification, the effort and expense of replacing a pump 300’ underground is quite an eye-popping justification (for me) to spend a bit more on a larger tank (let’s say a 5 gallon drawdown tank, for instance).
The idea that the tank takes up space is true enough except that I already have space being taken up by an 80-85 gallon tank and sure I’d get some of that back by using a smaller tank, but then all I would do is add more collectible goodies (or crap, as my wife refers to it) to my garage.
I would truly appreciate your feedback. Thanks so much.
Dave
1. 300 foot deep 1 1/2 HP pump with a "pump saver" electronic device...as during the summer the water level is scary low...in fact, our lawn/garden irrigation is minimal year-round.
2. I have a 80-85 gallon tank about 15 years old with a 40-60 pressure switch. Lately the 38 lb setting is getting hard to maintain without more frequent checks. I have begun to research tank options and found you.
I’ve been reading extensively about your product on your site and a plumbing forum that mentions you (meaning you and your product have a good reputation).
I totally understand the idea that a larger pressure tank is not needed with CSV, even though I come from the “if bigger is better then biggest must be best” era. I keep wondering if “only” 4.4 gallons with a 1 gallon drawdown could be correct for me. Let’s assume the following usage (currently two adults in the home, but it’s a two adult+three kid home and will be again someday):
Activity CSV Cycles with CSV Cycles with proposed
1 gal drawdown 5 gal drawdown
20 "1.6" gallon toilet
flushes throughout
the day…32 gallons 20 0-10*
1 shower…35 gallons 1 1
1 washer load…35 gallons 1 1
1 dishwasher load…14 gallons 1 1
5 meal prep and dish
cleaning…4 gallons 5 0
1 steeping bath fill…40 gallons 1 1
2 toothbrush and
Listerine procedures…2 gallons 1 0
Totals 30 4-14
* It’s true that 0 cannot be the true number for toilet flushes, as some of those flushes would trigger a cycle, let’s say half would…that still brings my total to only 14.
OK, OK…that’s enough personal info about my flushing habits…I hope you get the idea.
Your statement is as follows: “A CSV with a 4.4 gallon size tank (1 gal draw down) will cause the pump to cycle about 40 times per day on the average house. Using the CSV with a 20 gallon tank (5 gallons of draw down) will cause the pump to cycle about 20 times per day on the average house. In most cases, this is not enough difference to justify the use of any larger than a 4.4 gallon tank. The way the CSV controls the pump system, there is really no justification in using a larger tank. Then if you consider the cost and space needed, there is even less justification for using a larger tank.”
Cary…you write a great story…what I suggest you consider is an addition of some language that explains your most important conclusion, which is:
“Using the CSV with a 20 gallon tank (5 gallons of draw down) will cause the pump to cycle about 20 times per day on the average house. In most cases, this is not enough difference to justify the use of any larger than a 4.4 gallon tank.”
To me, it sure looks like it’s enough to justify a larger tank! Cutting the cycles from 40 to 20 is great, I’d say. You should explain why it’s not great, if that’s what you believe. If you suggest on the one hand that cycles are a pump-killer, then getting them down to the very minimum seems a logical goal…you must know something you are not saying…you must.
And speaking of justification, the effort and expense of replacing a pump 300’ underground is quite an eye-popping justification (for me) to spend a bit more on a larger tank (let’s say a 5 gallon drawdown tank, for instance).
The idea that the tank takes up space is true enough except that I already have space being taken up by an 80-85 gallon tank and sure I’d get some of that back by using a smaller tank, but then all I would do is add more collectible goodies (or crap, as my wife refers to it) to my garage.
I would truly appreciate your feedback. Thanks so much.
Dave