Replaced tank diaphragm

[Enis]

Hello to all.

I replaced the tank diaphragm and added air at 38.6 psi. After 20 minutes, it dropped to 37.2 psi. I tested schrader valve and around it with soap foam but found no bubbles. I also tested around the flange no bubbles. How could air leak?
(Note the tank is not yet installed in system)

Thank you for your time.

 

[MicEd69]

I assume you have a digital pressure gauge, correct? Do you know the accuracy of that gauge? Do you know the temperature of the air that you put in? Was this done in the sun outside or inside?

If the tank was warm, like in the sun, and then it cooled, you will have a decrease in pressure.

 

[Twowaxhack]

Hello to all.

I replaced the tank diaphragm and added air at 38.6 psi. After 20 minutes, it dropped to 37.2 psi. I tested schrader valve and around it with soap foam but found no bubbles. I also tested around the flange no bubbles. How could air leak?
(Note the tank is not yet installed in system)

Thank you for your time.

Soap the water connection if the tank isn’t hooked up.

 

[Enis]

I assume you have a digital pressure gauge, correct? Do you know the accuracy of that gauge? Do you know the temperature of the air that you put in? Was this done in the sun outside or inside?

If the tank was warm, like in the sun, and then it cooled, you will have a decrease in pressure.

Thank you for your response tank and air compressor was in same cool place about 2 days.

Features & details​

• Multi scales PSI,BAR,KG/CM2 & KPA
• Max pressure measurement 160 PSI or 11 Bar
• Display Resolition of 0.1 PSI
• Quick reset for next measuremet and single key operation
• Less than 2% inaccuracy

 

[Enis]

Soap the water connection if the tank isn’t hooked up.

Thanks i will tomorrow and let you know,
I will also test pressure too.

 

[Ludington]

I never realized you could change out a diaphragm. Is it actually cost effective to do that ? And where would you even get a replacement ?

 

[Enis]

I never realized you could change out a diaphragm. Is it actually cost effective to do that ? And where would you even get a replacement ?

Yes you can just unscrew flange and replace diaphragm is cost effective for me i live in balkan it cost 8$. Until the tank fail i keep replacing diaphragm.
The problem is we dont have quality tanks here all are chinese and from turkey they dont last for long.
You can find online to buy diaphragm any dimension u want.
Have good day

 

[Twowaxhack]

Yes you can just unscrew flange and replace diaphragm is cost effective for me i live in balkan it cost 8$. Until the tank fail i keep replacing diaphragm.
The problem is we dont have quality tanks here all are chinese and from turkey they dont last for long.
You can find online to buy diaphragm any dimension u want.
Have good day

Soap every seam on that tank. If the air is leaking it should show itself.

Could you remove the bladder and submerge it in water ? That’s how you can find small leaks in car tires.

 

[Ludington]

Yes you can just unscrew flange and replace diaphragm is cost effective for me i live in balkan it cost 8$. Until the tank fail i keep replacing diaphragm.
The problem is we dont have quality tanks here all are chinese and from turkey they dont last for long.
You can find online to buy diaphragm any dimension u want.
Have good day

I have an 86 gallon water worker tank. I don't see anywhere to get a diaphragm for it. I don't need one, just curious... that tank is running 499 at home depot at the moment. It would be nice to be able to swap the diaphragm if needed.

 

[MicEd69]

Soap every seam on that tank. If the air is leaking it should show itself.

Could you remove the bladder and submerge it in water ? That’s how you can find small leaks in car tires.

The OP said he has a diaphragm tank, not a bladder tank.

 

[Enis]

Soap the water connection if the tank isn’t hooked up.

I did soaped water connection no leak
I did meassured again now is 37.3
Ithink if is leaking would have dropped to 30 from last night

 

[Enis]

I have an 86 gallon water worker tank. I don't see anywhere to get a diaphragm for it. I don't need one, just curious... that tank is running 499 at home depot at the moment. It would be nice to be able to swap the diaphragm if needed.

I think they dont make replacement itentionally. To get new tank

 

[MicEd69]

I did soaped water connection no leak
I did meassured again now is 37.3
Ithink if is leaking would have dropped to 30 from last night

If your air compressor was empty and you turned it on just before adding the air to the tank, that air would have been a bit warm. And if you don't have a water trap on the air line, that would add to the change in pressure warm air would have cooling down to ambient. I think you are correct that it was/is some transient issue and not really an air leak.

 

[Twowaxhack]

I did meassured again now is 37.3
Ithink if is leaking would have dropped to 30 from last night

good, if you have any further doubt check it regularly.

 

[MicEd69]

LOL.

 

[Twowaxhack]

View attachment 45328
LOL.

What’s so funny about soaping a tank ?

 

[Valveman]

Any tank with a replaceable diaphragm or bladder is designed to fail. The bags rub the inside of the tank as the pump cycles on and off until it wears a hole in the bag or diaphragm. The best tanks are not repairable and have a diaphragm attached where it cannot touch the sides of the tank as it flexes up and down with each pump cycle. Any tank will last longer if the pump cycles are limited like they are when using a Cycle Stop Valve.

 

[Enis]

If your air compressor was empty and you turned it on just before adding the air to the tank, that air would have been a bit warm. And if you don't have a water trap on the air line, that would add to the change in pressure warm air would have cooling down to ambient. I think you are correct that it was/is some transient issue and not really an air leak.

Yes correct it was empty i tought about that later after posted , and compressor had to work 3 time to add air in tank. Air was warmer than the tank. An tank was cold. today added a bit more cool air to make 38.
I don't have water trap in air line if you mean in compressor.
For now is ok I will keep track air for sometime.
--
THe problem is i have water hammer when i quickly shut off faucet in kitchen noise come from bathroom .! Do u know what cause this problem. And how to fix without water hammer arrestor. I have galvanized old pipes.
Thank you

 

[Enis]

Any tank with a replaceable diaphragm or bladder is designed to fail. The bags rub the inside of the tank as the pump cycles on and off until it wears a hole in the bag or diaphragm. The best tanks are not repairable and have a diaphragm attached where it cannot touch the sides of the tank as it flexes up and down with each pump cycle. Any tank will last longer if the pump cycles are limited like they are when using a Cycle Stop Valve.

Yes valveman i agree with you, correct old diaphragm when i removed had sratched marks more around bottom.
Csv will do the job i know about it.
Thank you

 

[MicEd69]

What’s so funny about soaping a tank ?

Nothing, by apparently, you deleted that post as it only showed up in an E-Mail to me and not in this thread. Just didn't know why you would have deleted it.