Well pressure tank operation........need some opinions

JayBird · 12-27-2011, 04:13 PM

Hello all,

I'm wondering if I have an issue with my pressure tank. I feel the pump kicks on to much. I did some tests today and here is what I found. Let me know what you all think. First off, the pump does not kick on unless the pressure switch calls for it so I'm good there. No leaks

I'm not sure the gallon size of my tank, its just shy of 4 foot tall and measures about 16 inches across the top. (Don't have a fabric tape to get circumference)

Pressure switch is set to 50/30 and pump kicks on about 28 psi give or take depending on how accurate the gauge is. It cuts off at about 51 psi.

It takes roughly 5 minutes with one faucet running to drop pressure from cut off to cut in. Well pump can fill the take in about 1 minute.

I drained the pressure tank by faucet and opened the bottom valve on the tank to drain the remaining water. Tank pressure measured 25.5 psi with a tire pressure gauge. With a cut in pressure of 30. Like I mentioned earlier, cut in was about 28 psi according to the gauge so it seems the bladder pressure is close to where it needs to be or is it? Wondering if I need to add a couple pounds?

Does all this seem normal for a tank this size..... I wish knew the gallon size. Comparing mine with pics online it appears to be around the 30-32 gallon size. Maybe the bladder is a bit small for our demands. 2100sf house not including unfinished basement. 2 full bath, 5 sinks and 3 garden hose faucets, so there is a lot of piping.

Daniel Holzman · 12-27-2011, 04:46 PM

I have a similar setup, I have a well with the pressure regulator set to 50/30 like yours, and a Weltrol 82 gallon tank with a drawdown of 10.7 gallons from 50 to 30 psi. The drawdown determines how long your faucet can run before the pump kicks on. In my case, 11 gallons represents about 5 minutes of shower time, which is similar to what you quoted. I am note sure why you think there is a problem, the figures you quoted seem pretty normal.

JayBird · 12-27-2011, 05:01 PM

Quote:

Originally Posted by Daniel Holzman

I have a similar setup, I have a well with the pressure regulator set to 50/30 like yours, and a Weltrol 82 gallon tank with a drawdown of 10.7 gallons from 50 to 30 psi. The drawdown determines how long your faucet can run before the pump kicks on. In my case, 11 gallons represents about 5 minutes of shower time, which is similar to what you quoted. I am note sure why you think there is a problem, the figures you quoted seem pretty normal.

Maybe because If I'm in the house I can always hear the pump kick on, of course water is being used when it does. If I couldn't hear it each and every time I probably wouldn't be worried about it. I know my tank can't be anywhere near 80 gallons.

Daniel Holzman · 12-27-2011, 05:07 PM

Based on your dimensions, you have approximately a 40 gallon tank, which is smaller than mine. Again, the critical number is the drawdown volume of the tank, which is probably proportional to tank size, so I am guessing you have about half the drawdown volume I have, which would account for the pump cycling more frequently than mine does.

jproffer · 12-27-2011, 05:24 PM

Tank pressure should be about 2-3 PSI below cut-on pressure....in the OP's case, about 25-26....your's seems pretty normal. As long as you don't have any leaks, I wouldn't worry about it. If it's really bothering you (and it would have to be REALLY bothering me to go this route) you can change the tank for a bigger one.

Either way, tank pressure should be about 2-3 PSI below cut-on pressure.

Bob999 · 12-27-2011, 05:36 PM

Based on the dimensions you post the draw down for your tank is about 11 gallons. That number is consistent with a faucet taking 5 minutes to draw down the tank assuming ~2 gpm flow.

See here: http://www.aquascience.net/amtrol-pressure-tanks/

Note that the tank size is 32 gallons for a drawdown of 11 gallons.

A primary determinant of pump life is the number of starts so you would benefit from a larger pressure tank or a second pressure tank to reduce the number of start ups.

12-27-2011, 04:13 PM	#1
JayBird Member Join Date: Aug 2007 Posts: 58	Well pressure tank operation........need some opinions Hello all, I'm wondering if I have an issue with my pressure tank. I feel the pump kicks on to much. I did some tests today and here is what I found. Let me know what you all think. First off, the pump does not kick on unless the pressure switch calls for it so I'm good there. No leaks I'm not sure the gallon size of my tank, its just shy of 4 foot tall and measures about 16 inches across the top. (Don't have a fabric tape to get circumference) Pressure switch is set to 50/30 and pump kicks on about 28 psi give or take depending on how accurate the gauge is. It cuts off at about 51 psi. It takes roughly 5 minutes with one faucet running to drop pressure from cut off to cut in. Well pump can fill the take in about 1 minute. I drained the pressure tank by faucet and opened the bottom valve on the tank to drain the remaining water. Tank pressure measured 25.5 psi with a tire pressure gauge. With a cut in pressure of 30. Like I mentioned earlier, cut in was about 28 psi according to the gauge so it seems the bladder pressure is close to where it needs to be or is it? Wondering if I need to add a couple pounds? Does all this seem normal for a tank this size..... I wish knew the gallon size. Comparing mine with pics online it appears to be around the 30-32 gallon size. Maybe the bladder is a bit small for our demands. 2100sf house not including unfinished basement. 2 full bath, 5 sinks and 3 garden hose faucets, so there is a lot of piping.

12-27-2011, 04:46 PM	#2
Daniel Holzman Civil Engineer Join Date: Mar 2009 Location: Boston Posts: 3,583	Well pressure tank operation........need some opinions I have a similar setup, I have a well with the pressure regulator set to 50/30 like yours, and a Weltrol 82 gallon tank with a drawdown of 10.7 gallons from 50 to 30 psi. The drawdown determines how long your faucet can run before the pump kicks on. In my case, 11 gallons represents about 5 minutes of shower time, which is similar to what you quoted. I am note sure why you think there is a problem, the figures you quoted seem pretty normal.

12-27-2011, 05:07 PM	#4
Daniel Holzman Civil Engineer Join Date: Mar 2009 Location: Boston Posts: 3,583	Well pressure tank operation........need some opinions Based on your dimensions, you have approximately a 40 gallon tank, which is smaller than mine. Again, the critical number is the drawdown volume of the tank, which is probably proportional to tank size, so I am guessing you have about half the drawdown volume I have, which would account for the pump cycling more frequently than mine does.

12-27-2011, 05:24 PM	#5
jproffer Member Join Date: Mar 2005 Location: Chester, IL Posts: 1,140	Well pressure tank operation........need some opinions Tank pressure should be about 2-3 PSI below cut-on pressure....in the OP's case, about 25-26....your's seems pretty normal. As long as you don't have any leaks, I wouldn't worry about it. If it's really bothering you (and it would have to be REALLY bothering me to go this route) you can change the tank for a bigger one. Either way, tank pressure should be about 2-3 PSI below cut-on pressure.

12-27-2011, 05:36 PM	#6
Bob999 Member Join Date: Mar 2010 Posts: 268	Well pressure tank operation........need some opinions Based on the dimensions you post the draw down for your tank is about 11 gallons. That number is consistent with a faucet taking 5 minutes to draw down the tank assuming ~2 gpm flow. See here: http://www.aquascience.net/amtrol-pressure-tanks/ Note that the tank size is 32 gallons for a drawdown of 11 gallons. A primary determinant of pump life is the number of starts so you would benefit from a larger pressure tank or a second pressure tank to reduce the number of start ups.

Well pressure tank operation........need some opinions