Boiler Expansion Tank Dead End Example

dooododoo

Question: Is this an example of an expansion tank at a dead end?



It tee's off 6 inches to the right and 90's down to a valve.

Amtrol clearly states not to install on a dead end.

They also state install the tank vertically. It is not possible with where the tee is.

Do I need to call someone out to relocate the tank?

Bonus:

Is the proper expansion tank size for this boiler a 4.4gal, such as an Amtrol 102 30lb?



(Sizing chart for Watts' ETX tanks.)

Mark Eatherton

The tank is mounted fine, and no, that's not a dead end.

As for proper sizing, it depends on a bunch of variables, but if your pressure is staying within normal operating parameters, then I'd not worry about it. If pressure is between 12 and 27 pounds, and the pressure relief valve is not lifting, you're fine.

ME

hot_rod

looks like a domestic water expansion tank? Is it a 3/4 thread? Maybe why it tell you not to mount on dead end.

Solid_Fuel_Man

@hot rod it's a heating ex tank. Domestic ones are tan I believe. Zoom in and it says boiler expansion tank on it.

hot_rod

I thought it said Extrol. I'm use to the dark grey colored tanks. The first ThermTrols were tan like that. Or maybe it isn't tan?

dooododoo

It's dark gray in real life. I think the flash made the color look funny. But, yes, it's for closed boiler system.

dooododoo

hot rod said:

looks like a domestic water expansion tank? Is it a 3/4 thread? Maybe why it tell you not to mount on dead end.

No, it's 1/2"

hot_rod

Hopefully the checked and adjusted the pre-charge pressure. That should be adjusted to the cold fill pressure.

If the boiler is filled to 12 psi, the tank should be set to 12 psi before it is installed.

Nice that you have a valve there to service or check the tank.

dooododoo

The boiler is set at 15 PSI and so is the tank (loops goes up to 3rd floor). I noticed that when the boiler is cooled down, the temp is about 40 degrees and PSI is 15. When the boiler is running and aquastat cuts the boiler off, the temp is 180 degrees and PSI is 25. Is that a normal range of PSI? Would replacing the expansion tank with a bigger one reduce the PSI change? The new tank was replaced with the same one as the old (leaking bladder) tank. The boiler is 100,000 BTU/H. I'm thinking I should have gotten a bigger expansion tank such as a 4.4gal.

Mark Eatherton

dooododoo said:

The boiler is set at 15 PSI and so is the tank (loops goes up to 3rd floor). I noticed that when the boiler is cooled down, the temp is about 40 degrees and PSI is 15. When the boiler is running and aquastat cuts the boiler off, the temp is 180 degrees and PSI is 25. Is that a normal range of PSI? Would replacing the expansion tank with a bigger one reduce the PSI change? The new tank was replaced with the same one as the old (leaking bladder) tank. The boiler is 100,000 BTU/H. I'm thinking I should have gotten a bigger expansion tank such as a 4.4gal.

I think you're just fine. You need to stay at least 5 PSI away from the relief vale setting (30). You are there. Higher pressures are not detrimental to the components in the system. They are capable of handling much higher pressures that you are running.

What is more important is the relationship between the pumps location in relationship to the expansion tanks.

ME