bladder tank -whats up?

Users who are viewing this thread

boboiatl

New Member
Messages
2
Reaction score
0
Points
0
I have put a new bladder tank in my sons house and it does not seem to be filling with water. I took it off line and looked in the inlet for a plug or something that might be blocking it but all I see is what appears to be the bladder which I would guess to be normal.I put it back online and the tank stays empty -feels like no water at in it.Of course the pump cycles on and off like crazy . Do tanks come bad from the factory sometimes or am I missing something? thanks
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
You need to precharge the tank with the appropriate amount of air. This should be ~2 pounds LESS than the turn-on pressure of the pump control. SO if it is set to 30/50, it would be set to 28#. tO do this, you need to shut off the pump, open a valve and let the water run until it stops leave it open until you finish, then pump up the tank (or bleed off some air). SHut the valve and and turn on the pump and see what happens.
 

Speedbump

Active Member
Messages
4,511
Reaction score
12
Points
38
Location
Riverview, Fl.
Our bladder tanks come from the north east part of the country. I assume the elevation up there is much higher than here in Florida. The tanks that say they have a precharge of 38 psi. Sometimes have a precharge of around 50. If that's the case with your tank and your switch is set at 50 or below, your tank will not take in a drop of water.


bob...
 

Bob NH

In the Trades
Messages
3,310
Reaction score
9
Points
0
Location
New Hampshire
"Our bladder tanks come from the north east part of the country. I assume the elevation up there is much higher than here in Florida. The tanks that say they have a precharge of 38 psi. Sometimes have a precharge of around 50."

If you charge the tank to a specified gauge pressure at high altitude, the gauge pressure when measured at lower altitude will be LESS than the original setting.

EXAMPLE:
At high altitude (atmospheric pressure of 12 psia), charge to 38 psig; the absolute pressure will be 50 psia.

Measure the gauge pressure at sea level (14.7 psia); the gauge pressure will be 50 psia - 14.7 psia = 35.3 psig.

There isn't any manufacturing place in the northeast that is higher than about 1000 ft. That will make a difference of less than 1 psi if you measure the pressure in Florida.
 

Bob NH

In the Trades
Messages
3,310
Reaction score
9
Points
0
Location
New Hampshire
"Alright; so explain the higher than labeled pressure."

The factory quality control process is not perfect. They probably set the regulator wrong or some guy who couldn't read the instructions grabbed the wrong pressure labels.

Maybe someone incorrectly converted kPa to psi.

Whatever it was, it was not caused by any variations in atmospheric pressure.
 

boboiatl

New Member
Messages
2
Reaction score
0
Points
0
thanks for replies but...

I have done that-set the air pressure to around 2 below the cut in -but the tank does not seem to accept any water. The tank is still very light and system pressure is around 50 psi so I think the tank is not accepting water but could be wrong.I will try again your advice to make sure it is correct.Also my pressure switch only has a high cut off -low cut off is built in according to that.Is that normal or should I invest in a better switch which has both. thanks again to all who reply.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
Maybe it would be good to tell how you set and adjusted the pressure. You must do it with the pump off and a valve open. Double-check the piping, sometimes the galvanized stuff can get messed up with rust. Same is true for the input to the pressure switch - it must be clean or it will have trouble sensing the water pressure properly.
 

Pumpman

Pump Sales
Messages
190
Reaction score
0
Points
0
Location
So. Cal
In re-reading the first post, boboiatl says he looked in the inlet and saw what he assumed to be the bladder. I don't think I've ever seen the bladder looking at the inlet elbow. Any thoughts?
Ron
 

hj

Master Plumber
Messages
33,602
Reaction score
1,040
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
bladder

The inlet should not have an elbow. When removed from the system any bladder tank with more than zero pressure will expand to fill the tank. It deforms/compresses as pressure pushes against it.
 

Pumpman

Pump Sales
Messages
190
Reaction score
0
Points
0
Location
So. Cal
Thanks Speed.... I was pretty sure bladder tanks had an elbow on the bottom....
If the bladder was distended bad enough to be seen from the elbow, I'm sure the tank needs to be replaced.
Ron
 

Speedbump

Active Member
Messages
4,511
Reaction score
12
Points
38
Location
Riverview, Fl.
I will certainly agree with that. I really wonder if he is understanding the concept of checking the bladder pressure with the system pressure at zero?

bob...
 

Pumpman

Pump Sales
Messages
190
Reaction score
0
Points
0
Location
So. Cal
I don't know. Jim explained it pretty well in post #2.....that is, how to set the precharge correctly. I know I have customers that don't understand it.
Ron
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks