Expansion tank bladder gone

Tellyium

Hoping someone can help me figure this one out! I've an outside tank type pump in the shed taking in the mains water and powering the taps all over the house. This feeds into a system with a 3 bar cold water expansion tank (24litre).
Now it seems the bladder is ruptured as the expansion tank sounds 'solid'.
My issue is that there is a drain pipe below the expansion tank going through a 6 bar valve (I think?) and the water is constantly flowing out through the drain. Is this because the expansion tank is not pressurised?
Also, the tank was installed 'upside down' - why would this be so?
Thanks in advance!

Tom44

Tellyium wrote: »

Hoping someone can help me figure this one out! I've an outside tank type pump in the shed taking in the mains water and powering the taps all over the house. This feeds into a system with a 3 bar cold water expansion tank (24litre).
Now it seems the bladder is ruptured as the expansion tank sounds 'solid'.
My issue is that there is a drain pipe below the expansion tank going through a 6 bar valve (I think?) and the water is constantly flowing out through the drain. Is this because the expansion tank is not pressurised?
Also, the tank was installed 'upside down' - why would this be so?
Thanks in advance!

Your expansion tank is what it says on the tin !!
It's a shock absorber and room for water to expand into. Air will squeeze, water won't.

That's why your pressure release safety valve has blown and now leaking water.
Position of tank is not important as long as air filling valve, like on a car tyre is accessible, it's normally on the opposite side from the water connection.

Expansion tanks are useless unless serviced and refilled with air to the correct pressure to it's full volume, if not they will fail.

Tellyium

Tom44 wrote: »

Your expansion tank is what it says on the tin !!
It's a shock absorber and room for water to expand into. Air will squeeze, water won't.

That's why your pressure release safety valve has blown and now leaking water.
Position of tank is not important as long as air filling valve, like on a car tyre is accessible, it's normally on the opposite side from the water connection.

Expansion tanks are useless unless serviced and refilled with air to the correct pressure to it's full volume, if not they will fail.

Thanks! I hadn't realised the leak was due to pressure causing the valve to fail, but it makes complete sense to me now! Just understanding how it fits together now, and as you say, water don't compress.....
Thanks for taking the time to reply.

cerastes

Tom44 wrote: »

Your expansion tank is what it says on the tin !!
It's a shock absorber and room for water to expand into. Air will squeeze, water won't.

That's why your pressure release safety valve has blown and now leaking water.
Position of tank is not important as long as air filling valve, like on a car tyre is accessible, it's normally on the opposite side from the water connection.

Expansion tanks are useless unless serviced and refilled with air to the correct pressure to it's full volume, if not they will fail.

Do these lose pressure over time? Id have thought they would need to be fitted so no air would get trapped in the wet side of the diaphraghm? ie if fitted
The expansion tank in my heating system is fitted with the tank pointing downwards, Id considered this was so air present before the system is filled can more easily make its way out, although the valve is inaccessible as its right at the floor of the hotpress.

Wearb

cerastes wrote: »

Do these lose pressure over time? Id have thought they would need to be fitted so no air would get trapped in the wet side of the diaphraghm? ie if fitted
The expansion tank in my heating system is fitted with the tank pointing downwards, Id considered this was so air present before the system is filled can more easily make its way out, although the valve is inaccessible as its right at the floor of the hotpress.

That used to be considered the correct way (leaving access to valve, of course). I have since come across articles that say that this isn't necessary. I see lots of them fitted with valve uppermost and they seem to work ok. I don't know if it shortens the life of them or makes them less efficient. Anytime I have changed them, I have put valve lower, if I have room to do so.

phester28

not a plumber. but thinking about the physics of it. If the vessel was fitted with the air valve on the lowest point. One could test to see if there was water in the air side by momentarily pressing the valve in. I know we can check pressure, release a bit and then top back up to that value to keep the tank topped off with air. Obviously more correctly would be to depressurize the system and top up to the stated pressure.

Am I wrong in this thinking.

Wearb

phester28 wrote: »

not a plumber. but thinking about the physics of it. If the vessel was fitted with the air valve on the lowest point. One could test to see if there was water in the air side by momentarily pressing the valve in. I know we can check pressure, release a bit and then top back up to that value to keep the tank topped off with air. Obviously more correctly would be to depressurize the system and top up to the stated pressure.

Am I wrong in this thinking.

For a while after a bladder ruptures the air will act as an expansion absorber, but air will eventually be absorbed by the water and then you will get water at valve no matter what the orientation.
The first sign of a ruptured vessel will be a drop in system pressure (Assuming no leaks). Then after a topup water coming out the PRV when system warms up.