Adding a CSV1A and booster pump to existing pump system

[lake2164]

I am considering a CSV1A/PK1A but have a couple of concerns/questions.  I think the CSV might work, but want to double check my understanding.

Our current set up is a 20 year old Myers 1hp deep well jet pump pulling from a lake, set at 40/60 psi. I get a measured max flow at the pump discharge of 15-18 gpm.  It goes into an 86 gallon diaphragm tank.  I then have various filters after the tank.  The issue is the top floor of our single family house is 20+ ft above the pump house.  I get a measured static pressure drop of ~ 10psi at the house.  So with no water flowing I get 30/50 at the house.  With flow and of course some pressure drop across filters, we can get less than 30psi at the low end.  I would like to change that and target a constant (or near constant) 45-50psi at the house.

So to get 50 psi at the house I need 60 psi at the pump/pump house.  Now I don’t simply want to increase the pressure switch to 60/80 for a number of reasons.  Our pump hits 60 psi no problem, but does not like much higher than that.  I am sure it won’t hit 80 psi or even 70psi.  That plus the higher range would significantly reduce our tank draw down, and puts more pressure on our supply lines from the lake (which for other reasons would be bad).

What I am thinking of doing is putting a booster pump plus small second tank in series after all the filters with a check valve in the line from the current system main to the booster pump suction.  In this case, I would lower the current system to maybe 20-40 or so.  Then have the booster pump set at 50-70 with the CSV set at 60 (would give me roughly 50 at the house).

One other, possibly the biggest issue, is that we live in Texas and the pumps and plumbing are in a 6 x 12 un-conditioned pump house.  This year we have a had a lot of days of 100F+ days.  I actually monitor the temp in the pump house, and I looked back and even on 110deg days, the pump house only got up to 96-97 deg.

Now the questions/concerns.  While the temp seems to only have gotten to ~96-97 deg in the pump house, I see the CSV1A specs say max temp is 100deg.  It is also possible that there could be local spots hotter than where I have the temp probe.  Is getting close to that 100F on a possibly week or month long basis going to be a reliability problem for the CSV1A?

At a 50/70 booster pump setting, will a 5gal tank be too small and fill up/draw down too fast to keep a min 1 min on time and min 1 min off time (would the pump cycle too much).  Would a 10 gal or even 20 gal be better?  I see a post where you suggested a 10gal for a 50-70 setting so I suspect the answer is still yes.  Now I understand that the CSV holds a relatively constant pressure (subject to reduced pressure fall off) when the pump is on.  When it is off you will see the total pressure tank range.  This means when you turn on a faucet you will see a high pressure falling off to the low setting until the pump comes on and the pressure stabilizes at the CSV setpoint, correct?  I assume this is why a smaller tank works better, because the small (but not too small) draw down minimizes the time of that dropping pressure?

Any issue using the booster pump + CSV after the main pump+tank+filters?

One last thing, talking of pressure, how do you get the total pressure drop across the CSV from the tables?  For the CSV1A at 10 gpm is it a total of about a 10psi drop (5 psi for friction and 5 psi for reduced pressure fall off)?

Thanks

[Cary Austin]

You could use a booster pump but that doubles the equipment and complications.  A deep well jet should be able to build at least 80 PSI max, which means you can use it with a CSV set at 60 and a 50/70 pressure switch.  Best to not double pump as long as the main pump can do the job.  Even it the main pump is too small, replacing it with a larger pump is better than adding a booster. 

The only time you will even see friction loss from a CSV is when trying to use max flow from the pump, which is usually rare.  Reduced pressure fall off can be made up for by setting the CSV adjustment 5 PSI higher when running a 3 GPM small flow.  You will just have 5 PSI less when using a large volume of water.

I am in Texas as well.  100F degrees Lol!  That is the water temperature.  Hope you have cooler water than 100F?  The temp in the well house doesn't make any difference as the CSV has no electronics that would be destroyed from high ambient temperature like a VFD would be.

Small tank or large doesn't make any difference to the CSV.  But as you said you would see the strong constant pressure much sooner with a small tank compared to a large tank.  At 50/70 you need at least the 10 gallon size tank, as at higher pressures tanks hold less water.  But the 1 minute run time is no longer important as the CSV will not cycle the pump every minute or two like it would without a CSV.  But you should still get a minute of run time using the CSV with the 10 gallon tank, even though it is not important.  Using the small tank with the CSV, the run time will be determined by how long you use the water plus another minute to fill the tank.