Bladder expansion tank connections?

[goosegunner]

I have used a 120 gallon propane tank for my expansion tank for 4 years. I found a few bladder tanks and I want to switch over. I have a 1/2 inch copper line running to the bottom of my current tank. The new bladder tanks have connections on the top which I find kind of strange.

I want to be able to bleed air from the line going to the top of new bladder tanks. What is the best method or valve to use to the top of bladder tanks?

Does the height of bladder tank matter?

Should I just place on floor or can the be elevated on a rack?

Old tank below with new bladder tanks following.

 

[Bob Rohr]

What brand of tank, Zilmet by chance? Most of the Euro tanks have BSP straight threads. They connect with a nut, tailpiece, and gasket.

 

[goosegunner]

The tanks are Elbi.

 

[Bob Rohr]

The tanks are Elbi.

View attachment 140357

An Italian made tank. Their pdf shows a NPT thread. try a regular pipe fitting. If it only goes on 1 thread it is probably a BSP straight thread.

A small brass air vent on the line to the tanks would work, pipe it at the high point. Install an iso check or ball valve below it for ease of service.

 

[Armaton]

Problems with the original setup, or just fell into bladders and want to try them?

 

[goosegunner]

Problems with the original setup, or just fell into bladders and want to try them?

I have had a few annoying issues with air noise in my system. I am not sure why but I would suspect something with my air filled expansion tank.

I found the bladder tanks on the classified section on this site and they were only 1.5 hours from me for a decent price. I decided to try an upgrade.

That and the fact that I can change my vertical tank to a buffer tank in my basement to have hot boiler water close to my system for DHW set up.

gg

 

[Bob Rohr]

Ther are some fine points to installing a non bladder compression tank, in a closed pressurized system. Ideally you need an air control valve that pulls air from the boiler for example and puts it to the top of the tank. The dip tube helps keep the air from being re-absorbed also.

Regardless you cannot fool mother nature, as the water heats and cools it can and will move into and out of the piping. Devices like the B&G AirTrol fitting can minimize, but not eliminate the issue.

Here is part of an article from Rite Boiler regarding compression tanks, also.

The bladder style expansion tank really did revolutionize the hydronics industry, credit Amtrol for that invention.

 

[goosegunner]

Ther are some fine points to installing a non bladder compression tank, in a closed pressurized system. Ideally you need an air control valve that pulls air from the boiler for example and puts it to the top of the tank. The dip tube helps keep the air from being re-absorbed also.

Regardless you cannot fool mother nature, as the water heats and cools it can and will move into and out of the piping. Devices like the B&G AirTrol fitting can minimize, but not eliminate the issue.

Here is part of an article from Rite Boiler regarding compression tanks, also.

The bladder style expansion tank really did revolutionize the hydronics industry, credit Amtrol for that invention.

Thanks for the info Bob, That probably explains why I am having noise. I don't have the special dip tube in my tank and my compression tank is connected to my Taco 4900 air separator. I hope the new bladder tanks improve my system.

gg