expansion tank

[clawman]

Does it matter where the expansion tank is within the system? I see it mounted in numerous locations.
Cold side?
hot side?
in front of the recirc pump?
???

 

[rlitman]

On the suction side of the pump(s).

 

[dogdog]

Never side ways

Upside down or right side up only

 

[rlitman]

Never side ways

Upside down or right side up only

Well, sideways can work, but only with adequate support. Vertically mounted, the threaded ****** should be plenty for any residential sized Extrol tank.

 

[LS6 Tommy]

Never side ways

Upside down or right side up only

That only applies to unsupported bladder style tanks. A tank without a bladder is almost always laid horizontally.

Tommy

 

[dogdog]

That only applies to unsupported bladder style tanks. A tank without a bladder is almost always laid horizontally.

Tommy

Well.....in accumulators , it is not recommend because of some uneven wear of seals, probably the same thing would apply for expansion tanks... Not sure.. I have always seen it vertical...

 

[rlitman]

That only applies to unsupported bladder style tanks. A tank without a bladder is almost always laid horizontally.

Tommy

Yes, but the old tanks without bladders also were awful on your system. Every heating cycle, your water expands into them, and the tank gives a space for the water to absorb some air. Then the oxygenated water cools and returns into circulation. On the next heating cycle, the air bubbles out and circulates.

Over time, the water level in the tank rises, and you need to regularly empty it and let more air in to restart the corrosion cycle.

Ever since I got my first Extrol tank, I stopped having to annually bleed my radiators.

 

[LS6 Tommy]

Yes, but the old tanks without bladders also were awful on your system. Every heating cycle, your water expands into them, and the tank gives a space for the water to absorb some air. Then the oxygenated water cools and returns into circulation. On the next heating cycle, the air bubbles out and circulates.

Over time, the water level in the tank rises, and you need to regularly empty it and let more air in to restart the corrosion cycle.

Ever since I got my first Extrol tank, I stopped having to annually bleed my radiators.

No argument from me. My tank is probably original to the house. My Weil-McLain P366 boiler is probably about 35 years old. I keep saying I should replace the tank with an extrol, but in all honesty, it will probably stay the way it is until I replace the boiler.

Tommy

 

[clawman]

On the suction side of the pump(s).

Most pictures I've seen have the pump after the heater (why I do not know) so you are saying the expansion tank should be between the heater and the pump?
Thanks

 

[rlitman]

Most pictures I've seen have the pump after the heater (why I do not know) so you are saying the expansion tank should be between the heater and the pump?
Thanks

Yes, exactly. The expansion tank should be sited at the Point Of No Pressure Change.

 

[LS6 Tommy]

Pump location should be based on boiler manufacturer's instructions, but most are on the return side of a high mass system, with the exception being if there is an air purge/eliminator/scoop and a bladder style expansion tank, the pump goes on the supply, upstream of the air removal unit and tank.

Tommy

 

[brewchief]

Expansion tanks should be mounted so they hang down with the connection on top, Extrol specifies this in their instructions. If you mount it with the tank up it can collect air, air+water=rust. Larger tanks designed to sit on the floor are an exception of course. If you have an open system or a system that doesn't have oxygen barrier tubing you can buy a tank that is fully lined so it won't rust out.