Pitless adapter is undersized. Replace or leave in place?

[plowhog]

My new residence is serviced by an old well. Circa 1995, 2hp motor, about 25gpm +/-. The existing bladder tank is shot, the system sometimes short cycles, plus it is .... old. So I've decided to install a new pump, motor, and constant pressure system.

My well guy advises leaving the existing 1" pitless adapter in place. He says it is "too much trouble" to change, as it requires excavation, blah blah. My pipe from the well to the house is 1 1/4. All piping in the (new) residence is 1 1/4. Except for tie-ins at each plumbing fixture.

After spending the $$ to do this, I'm leery of having a 1" section of *anything* in place, as it seems like an obvious restriction on flow. But my well guy says it is "no big deal." He says a short section of 1" is not going to be a noticeable restriction even though everything else is 1 1/4 lines.

Two other things: a) I also have a 250' run of 1 1/4 pipe to my shop, where I plan to add future 1" rainbird sprinklers for the pasture, and, b) the house was recently re-plumbed up to 1 1/4 lines as the original (smaller) pipe size caused pressure drop and volume issues.

I get it that doing excavation is not desirable, will tear up the landscaping, and could get expensive. (I do have a small backhoe.) But I'm leery of his advice that it is "no big deal." But I don't have any practical experience to draw from, so I can't evaluate whether it is truly not an issue or this is just work he doesn't want to do?

Any thoughts or ideas?

 

[oosik]

Lets see ...... your 1" pitless is bronze, right. So it will never rust out. If you change it out now it will mean extra digging. If you change it out six months from now - it will mean the exact same digging - right. I would go with the existing pitless and see how it works.

When you installed the new pump - you ran 1 1/4" pipe from the pump up to the old pitless then installed a reducer to hook on to the pitless. On the outbound side of the pitless there must be an "increaser" fitting. To get from 1" pitless to the 1 1/4" pipe running into the house.

I'm just trying to get the correct picture in my mind............

How was the volume & pressure under the old system? If it was OK then use the existing pitless.

 

[TnAndy]

Lets see ...... your 1" pitless is bronze, right. So it will never rust out. If you change it out now it will mean extra digging. If you change it out six months from now - it will mean the exact same digging - right. I would go with the existing pitless and see how it works.

When you installed the new pump - you ran 1 1/4" pipe from the pump up to the old pitless then installed a reducer to hook on to the pitless. On the outbound side of the pitless there must be an "increaser" fitting. To get from 1" pitless to the 1 1/4" pipe running into the house.

I'm just trying to get the correct picture in my mind............

How was the volume & pressure under the old system? If it was OK then use the existing pitless.

I didn't pick up anything in the original post about the pump to pitless adapter size of the pipe....though maybe that was inferred with the talk of restriction.

Not really that big a deal to dig down to the adapter. You might have to torch or grind a larger hole to get the bigger one to go in....most time, they use a hole saw, but since the hole is already there, no place for the center bit. Guess you could move the hole to a new place on the casing and put some kind of patch over the old hole......

 

[Valveman]

Your pump man is right that a short piece of 1" is not going to restrict you at 25 GPM. If you were going very far with 1" that would be a problem. Hope you haven't purchased that constant pressure system yet. There are two ways to get constant pressure. Most pump guys will try to sell you the variable speed type of pump that will cost several thousand more than a standard pump and will only last a fraction as long. You can also use a Cycle Stop Valve to make a standard pump become a constant pressure system. This system is disruptive to the pump industry because it actually makes standard pumps last much longer than normal and cost a fraction as much as those variable speed pumps.
Pressure Tank Replacement, Constant Pressure Pump, VFD, well pump, booster pump on Vimeo

How a Pressure Tank Works and why you need a Cycle Stop Valve on Vimeo

 

[3Ts]

The pitless adapter is essentially a 90* fitting. For 1" pipe a 90* fitting is equivalent to 2.6' of 1" pipe. For 1.25" pipe a 90* fitting is equivalent to 3.5' of 1.25" pipe. I doubt that you'll be running 25 gpm all the time so I don't think changing out the pitless adapter is going to get you much if anything.

At 25 gpm and 1" pipe your velocity is 9.7 ft/sec with a friction loss of .142 psi/ft, so your pressure loss thru the 1" pitless adapter will be 0.369psi. If you change it out to a 1-1/4" adapter, 25 gpm, your velocity is 5.5 ft/sec with a friction loss of .037 psi/ft with a pressure loss of .130psi. You are only looking at a difference of 1/4 psi drop by leaving it in at a max flow rate of 25 gpm. Using a lower flow rate will be even less of a pressure drop.

 

[plowhog]

I didn't pick up anything in the original post about the pump to pitless adapter size of the pipe....though maybe that was inferred with the talk of restriction.

The pipe inside the well, from the pump to the pitless adapter, is continuous "black" pipe. I believe it is 1 1/4. The well guy said after removing that he will install 1 1/2" pvc going to the new motor and pump. I believe he uses schedule 80 inside the well. If that is correct I will have 1 1/2 inside the well, connecting to a 1" pitless adapter, then 1 1/4 going to the house and my shop.

I did have pressure and flow troubles when the house was originally plumbed using only 3/4" feed lines (necked down from the incoming 1 1/4). Back then, when the master shower (or tub) was used, the kitchen faucets would reduce to almost a drip. That was all recently changed with the 3/4" lines being replaced with 1 1/4". That dramatically increased pressure and flow.

The unknown is my irrigation near my shop. I've never yet tied into it, so I don't know what to expect. I have 1 1/4" line from the well to the shop running 250' on a slight uphill grade. My bath and shower in the shop works fine, but I have a 1" irrigation line T'ed off of that which I want to use for sprinklers in the pasture this summer. That's why I'm wondering if an undersized pitless adapter would be a significant, or insignificant, restriction.

The closest similarity I could think of would be running 3/4" sprinkler pipe in a lawn, but only using a 1/2" valve. That would seem to add an undesirable restriction. But without any practical or real-world experience I can't deduce if it is significant or not.

btw, I looked at the cycle stop valve info. (I can't run the video as I am on HughesNet right now.) I don't understand how they work. And, information I read regarding cycle stop valves all reference small pressure tanks. Usually, the VFD constant pressure systems have small expansion tanks, but my well guy wants to put in an 81 gallon pressure tank due to the irrigation sprinklers already in place plus the ones I want to add. (Currently have about 40 lawn sprinklers on 11 zones, going to add 10 more 1 inch sprinklers on several zones.)

Right now I'm leaning toward excavating since the pitless adapter is only down about 4 feet. But I'm not sure if that's truly necessary, and now I'm further wondering about the cycle stop valve method?

 

[Valveman]

I commonly use a 1" pitless in 5" PVC casing so there is room for a 4" flow inducer shroud to pass the pitless. As was stated you won't loose but 1 PSI through that pitless even at 25 GPM flow. With a real constant pressure system the pump is only producing as much as you are using, and you will rarely use 25 GPM, even though it is available. I say "real" constant pressure system because many of them do not work that way. Some of the variable speed pumps or controllers (called VFD's) like the Pentair PID do not vary the speed of the motor. They are basically just a soft starter and claim they can soft start hundreds of times a day without hurting the pump/motor, but that is not really true. I think your well man maybe using one like this because he is recommending an 80 gallon pressure tank. An 80 gallon tank only holds 20 gallons of water, but it will greatly reduce the number of cycles or starts when using one of those type systems. These type VFD's will turn the motor off after it has run at a steady flow rate for 60 seconds. If the pressure drops as the tank is delivering the water, the controller knows you are still using water and turns the pump back on. This causes the pressure to go up and down over and over, similar to the old pressure tank only method using a 40 on and 60 off pressure switch. Not really a constant pressure system as advertised.

There are more sophisticated and expensive VFD's that will vary the pump speed to match the flow being used. However, they take more care in setting up as you need to figure the minimum RPM the pump will still produce water and adjust other settings. But these type will vary the motor speed to match the pump flow to the amount being used. This is done by maintaining a constant pressure. If the pressure drops below 50 PSI, the motor speed is increased. If the pressure increases above 50 PSI, the motor speed is decreased. The flow from the pump will be exactly as much as the sprinklers and things are letting out. Only when the pump runs at the minimum speed programed in for a certain length of time will the motor shut off. The flow is going right past the pressure tank, so a small pressure tank can be used. A slight drop in pressure starts the pump all over again.

Although constant pressure is a wonderful thing and solves many problems associated with the old pressure tank method, using a computerized system like a VFD can add back many other problems. The idea of the VFD systems is to have something that sounds cool, is expensive, doesn't last very long, and must be replaced quickly as it supplies your water and is not repairable.

Sorry you can't see the video. To be such a simple valve the CSV has a complicated explanation, but I will try. The Cycle Stop Valve was patented in 1993 as a way to replace troublesome and expensive VFD's and large pressure tanks. Basically it uses the same standard and long lasting pump with a normal 40/60 pressure switch and will work with a much smaller tank. All the pump manufacturers tested the CSV in 1994 and blacklisted it as a disruptive product. The quote was, "Cycle Stop Valves make pumps last longer and use smaller pressure tanks. This company makes pumps and tanks, so any employee who mentions a Cycle Stop Valve will be terminated immediately".

The CSV is just a simple valve that maintains 50 PSI as long as you are using more than 1 GPM. It just has a 50 PSI spring to operate the valve. It will work with any size tank, but large tanks as not needed. Whatever size tank you have must drain from 60 to 40 PSI as normal before the 40/60 switch will start the pump. Once the pump is started the CSV knows how much water you are using by maintaining 50 PSI constant. If the pressure drops to 49 the valve opens and gives you more water. If the pressure goes up to 51 the valve gives you less water. Only when you stop using water will 1 GPM, which bypasses through the CSV, go into the pressure tank until the pressure reaches 60 and the pump is shut off.

The old pressure tank only method was very reliable. Nearly every problem with a pressure tank system was from the pump cycling on and off. Cycling wears out the pump, motor, pressure tank bladder, pressure switch, check valve, start capacitor box, stirs up the well, and delivers pressure varying from 40 to 60 over and over to the house. Simply adding a Cycle Stop Valve solved most if not all of those problems, making a dependable system even more so. Not to mention deliver a strong constant pressure to the house. Maintain 50 PSI constant seems so much stronger in the shower than when pressure is continually varying from 40 to 60 that many people tell me they no longer even need soap. Lol!

The CSV has been replacing troublesome VFD's and large tank systems for nearly 30 years now. Pump guys don't like it for all the reasons mentioned. But homeowners love it for all the reasons mentioned.

 

[plowhog]

Some of the variable speed pumps or controllers (called VFD's) like the Pentair PID do not vary the speed of the motor. They are basically just a soft starter and claim they can soft start hundreds of times a day without hurting the pump/motor, but that is not really true. I think your well man maybe using one like this because he is recommending an 80 gallon pressure tank.

He quoted a Subdrive 20, which supposedly varies the speed of the motor based on changing the frequency. As I understand it, there is a phase converter to allow a single phase house wiring to use a 3 phase pump, so that it can be spun at variable speeds from slow to top speed.

I will watch the cycle stop valve video when I get to a better internet connection. In the meantime, I found many great claims about what they do, but cannot find an explanation of how the benefits are achieved. I cannot figure out yet a) what it controls, or b) how it control it. Does a cycle stop valve control the motor on/off, or motor speed? Is it able to modulate flow to points between on and off? Maybe the video explains that but I can't find an explanation of the science or engineering of the CSV.

 

[Valveman]

The CSV is just a simple valve. It closes to reduce the flow and opens to increase flow based on pressure. You could do the same thing with a ball valve and a pressure gauge if you sat there and watched it 24 hours a day. Anytime the pressure was below 50 PSI you open the valve a little. Anytime the pressure got higher than 50 PSI you close the valve a little. The CSV just has a 50# spring that pushes the valve open when there is less than 50 and lets it close when there is more than 50 PSI. The seat on the ball valve is basically cut so it can't close less than 1 GPM. If pressure just keeps climbing and you close th eball valve, the 1 GPM leaking through has no place left to go except the tank. The tank then fills to 60 PSI and the regular pressure switch shuts the pump off.

Subdrive can be used with a switch or a transducer. The switch turns the pump on and off 45 times a minute to maintain pressure within 1 PSI, it does not vary the speed or flow. The transducer does vary the speed and flow, but uses a sleep mode to turn the pump off and back on. Sleep mode won't use but maybe 5 gallons out of an 80 gallon tank before the pump starts. Either way continually ramping up and down the pump is not good for it. Also, the three phase motor is just to lock you into replacing the Subdrive controller 2-3 times before you realize it would cost less to pull the pump and replace the three phase motor with a standard single phase. With the three phase motor you must have the Subdrive to convert normal single phase house current to three phase to run the three phase motor. Kind of a Tar Baby set up as you can't get away from the Subdrive or something similar until you change the motor.

Bottom line is the pump man makes a lot of money on Subdrives, which is not good for the homeowner. Pump men don't make much on Cycle Stop Valves, which is why they don't tell you about them.

 

[plowhog]

Thank you for the detailed explanation. I think I saw some of your posts on another forum as well. I will certainly research this before proceeding. Much appreciated.