Well Tank Size

Hi Guy's, so it's time to order things for the new basement now that the floor has been poured. I have a 36 gallon well pressure tank now, I am thinking of going with a 44 gallon. I know there supposed to me matched to the pump, however all I know is my pump is 76 feet down, don't know anymore.

I'll take any and all advice, thanks..

if the pump has n o problem keeping up w/ the 36 gal then go for it

Why do you need a new tank? I'd use the old one until it dies.

I'm not a large tank is a better tank guy....some argue a larger tank has benefits, but I don't see them as show stoppers. If you have a valid reason for a larger tank, fine, but if it's large just for the sake of being large, I'm not sold.

If it is a jet pump it makes no diffrence. If it is a submersable pump, it should run for 1 to 11/2 min. to properly cool motor. This will also cost less to run and save the start windings from going bad faster. At that depth it's not that big a deal to change the motor whenever the pump dies. When it starts getting down below 250 ' it pays to do anything to extend the life of the pump.

I doubled my tank size. So far the pump has been going for 8 years when I didn't expect to get 5 out of it, due to the crooked bastard that installed it.

Anything I can do to avoid doing this for as long as possible, I'm all for it ... so I've doubled the tank size & adjusted the pressure settings for a wide spread (28-68 psi). So far, so good ....

......but now I've gotta go find some wood to knock on.

Freddy wrote:Why do you need a new tank? I'd use the old one until it dies.

I'm not a large tank is a better tank guy....some argue a larger tank has benefits, but I don't see them as show stoppers. If you have a valid reason for a larger tank, fine, but if it's large just for the sake of being large, I'm not sold.

Thanks for the reply's guy's. Since all my gear is getting old, 15 years, and I want to build the new system in the basement and get it plumed in and then make the switch I will need new gear. I don't want to take the house off line for more than a few hours.

plumb-r wrote:If it is a jet pump it makes no diffrence. If it is a submersable pump, it should run for 1 to 11/2 min. to properly cool motor. This will also cost less to run and save the start windings from going bad faster. At that depth it's not that big a deal to change the motor whenever the pump dies. When it starts getting down below 250 ' it pays to do anything to extend the life of the pump.

1 to 11/2 min? Please explain..

The 'ON' cycle would complete it's task in a minute of two, and not run for 30 minutes....HOWEVER, suppose you are filling a pool (just an example, guys). Some motors are designed for continuous duty, but not all of them. Plumber is stating that if you overuse or overheat the motor, you are on a fast track to the supply house for another motor. Submersibles are usually 100% duty cycle...no chance to overheat when you are in 50 degree water......
I get into knock down, drag-out battles with anyone whom I don't believe and I can tell you that, and I say: have all the storage you want.....gang tanks together if necessary and fill them all at the same time.
Well recovery is now longer term, because you have a greater supply on hand, and I prefer to not SHORT-Cycle any equipment. On/off, on/off sucks, and I don't care if you are a Hydraulic Engineer with 50 years under your belt.

Water bottling companies up here like Belmont Springs or even Poland Springs use the same method I recommend, and they do millions of gallons every week, 24/7. Short cycles ruin pumps....my $.02.

A larger tank gives you more consistent water pressure especially if you existing tank is too small. You should be able to take a 5-7 min shower without having water pressures changes. Maybe your existing tank is large enough for your family? How many water users live in your home?

As Whistlenut stated, you can pipe two tanks in parallel even if they are different sizes. If your original tank is a Well-trol, best tank available and may continue to last quite a while, it'd be a waste to junk. If you need to increase in size, buy a 2nd tank and pipe accordingly. I did, the system has been trouble free. The well pump operates off of water pressure in the tanks, not liquid level. Once my smaller tank reaches its liquid volume full level, the larger tank will continue filling until the system reaches 52psi.

The act of water flowing past the motor to the water end of the pump is what cools the motor. I've worked by the C&D canal in Maryland and some of the BIG houses there will use the canal for lawn sprinkler. We always sleeve the pump with a piece of 4"-6" pipe a couple of feet long to force the water to draw past the motor. If we don't the motor goes bad fast from over heating , eventhough its made for constant duty they still can bake. Bottom line, you pay your money, you take your chances.

Ok The more I learn the less I know. Can someone tell me the difference between a two wire pump and a three, my pump has two plus a ground, but is 230 volt. I looked around and saw that a two wire can be 115 volts or 230 volts, so what is a three wire, 3 phase?

Let me add, I looked at my well tank, it says it is a 36 gallon equivalent to a 82 gallon conventional tank, now I'm really confused..lol


I have it set 45 psi on 65 psi off, it will run 1 minute 10 seconds to fill up with no load.. however I don't know how many gallons are discharging , sure don't think it's 36 gallons. last I checked the bladder pressure was 38 psi, which is wrong for a 45 kick in, better go get the tire gauge..

Another add, I had it full, killed the power and opened up and let it drain out, the switch kicked on at 44 psi, about 4 seconds later the water stopped flowing, thats about right. I did not check the bladder pressure thou.

Whats got me thinking now is the few minutes it took the bathroom sink to empty the system I can't see that being 36 gallons of water. Based on my above post I am wondering what does the rating really mean? If it is a 36 gallon tank I would think once it is filled it should hold/output 36 gallons, but it sure did not seem like it.

Is there something I am missing?

Those 'equivalent gallons' of storage are a bunch of crap. I don't know the logic behind the ratings, but it amazes me that they so optimistic. I'm sure it is 'well defined' someplace in the sales literature, but since most of us live in the real world, it makes absolutely no sense at all. i have from 47 to 120 gallon xtrols, and there is no logic when you look at a tank that says 47 gallons and your mind pictures a tank the size of a 55 gallon barrel......and you say 'NO F......Way! The 120's are even more dramatic...... If you shut down a 120 gallon tank, you'd be hard pressed to get 30 gallons out of the pressure bladder side of the thing.

Thought you'd luv to hear more confusion about 'equivalent storage'.

Regarding the wiring, old 230/220v lines had no neutral. 2 hots and ground was it. Now code rules the day. Now all 230v setups have 4 wires -- 2 hots, neutral, and ground. 120v has 3 now -- hot, neutral, & ground. Old 120v ones could have left the ground out, having only hot & neutral.


My old tank I pictured in another thread held 6 gallons (first pic below). I estimate my new one to hold 3x that since it runs for 3x longer than the old one ... so 18, when it says it's a 40-something gallon capacity. I agree with Whistlenut - that's my reason for suffering through a wide pressure spread, and increasing the tank size.