Flooding expansion tank

[cityboy172]

Alright, ever since I pressurized my system full time, My expansion tank has been flooding. The tank is a salvaged 250 gallon pressure vessel. It is in the rafters above my storage, in my barn with my EKO60. The only spot that is higher then the boiler room, and not by much, is a run of fin tube that serves upstairs in the house.

System pressure is around 10-12psi cold, the expansion tank was off the Caleffi discal, moved it to the dirtcal hoping a colder spot would help, but it didn't.

Any Ideas? I'm running out of places to move it to. About to start shopping for bladder tanks if I can't get this resolved.

 

[BadgerBoilerMN]

A properly size bladder tank is the only choice for a closed hydronic system.

 

[cityboy172]

A properly size bladder tank is the only choice for a closed hydronic system.

Yeah, not sure why I thought this would work good here. I knew better. My Inner cheap ass got me again.

 

[goosegunner]

While others on the site have had good luck running those set ups. I had issues with air getting into my system from the tank. I switched this year to Bladder tanks and it has been much better. Not really sure why my system absorbed air with air charged tank but so far I am happy with the change to bladder tanks. I think to have a proper set up you need to have the valve that will return absorbed air back to the air space in the tank from your air separator.

gg

 

[ewdudley]

ny Ideas? I'm running out of places to move it to.

If the tank is flooding then gas must be leaving the system. First place to look would be fittings on the top of the tank itself. Brush or spray bubbly solution and see where the gas is leaving the system. If you have an air separator it must be vented up to the expansion tank, or at least it must be valved off so no air can escape the system.

 

[cityboy172]

If the tank is flooding then gas must be leaving the system. First place to look would be fittings on the top of the tank itself. Brush or spray bubbly solution and see where the gas is leaving the system. If you have an air separator it must be vented up to the expansion tank, or at least it must be valved off so no air can escape the system.

My thoughts too. Haven't pinned anything down yet. Might pressurize higher tomorrow with the compressor.

 

[Bob Rohr]

My thoughts too. Haven't pinned anything down yet. Might pressurize higher tomorrow with the compressor.

Isolate the tank and pressurize it to as high as the rating plate allows, sounds like a pinhole leak somewhere.

 

[maple1]

A properly size bladder tank is the only choice for a closed hydronic system.

Not sure I agree completely with that - maybe the better choice depending the situation. Compression tanks have been used for decades with no issues.

I have a compression tank setup too - I couldn't help myself, I had to at least try it seeing what the recommended size of bladder expansion was going to cost. It's a 110 gallon LP tank, sitting upright on the floor right beside my storage. So about the worst spot for it as far as air-into-water issues goes, at the lowest place in the system. It is also only about 4' from the inlet of my load circ. I do get a bit of air in the water, that seems to work it's way up the zone return piping into one upstairs zone. I have had to bleed the air out of that zone, twice now this winter, due to an airlock. I also have another compression tank, a 20 gallon one, up in the joists above the boiler. It was there for the old boiler, I just left it there & hooked to the new one. I have since decided that I should try to do something about the 110 gallon LP tank, and after racking my brains for a couple of years on my space issues & where & what to do, I got a sx90v sized bladder tank, and will be putting it in the same place as the LP tank this summer. It'll require a bit of demo & recon work under the basement steps to get things in & out. It is not big enough alone for my storage size, but together with the 20 gallon one up high it should be - and I also got another 15 gallon compression tank that I will be putting even higher in the ceiling at the top of my basement steps, tied to top of storage. If I could find a high place to move the LP tank to, I would do that instead - but the only two possibilities are way up in the attic on the other side of a 2' wide hatch, or in the master bedroom. Neither of which are happening.

Agreed with above - there must be air getting out, somewhere.

 

[cityboy172]

I've got one spot that might be suspect. I'll look into it in a little bit. Been a bit nuts around here this morning.

 

[cityboy172]

Ok, so here's the update for anyone interested. The tank was a 250 gallon expansion tank, that was salvaged off a job. It had everything on it, sight glass and "Air charging" boiler drain. The problem was in the air charger. The tube was not previously cut, so it went almost completely to the top of the tank. The air bleeding screw that also holsds the handle one, was damaged and continuously bleeding air out.

So in the course of about 3-4 days, I would completely loose my air charge. I was draining it out and recharging the tank with air before the water could get to the tube, so even though the tank was almost completely full of water, no leaks were ever visible. Replaced it with a ball valve that I had around, and time will tell, but I am fairly confident that the issue has been resolved.

I appreciate anyone who helped here, and hopefully this is the end of the problem. Here is a stock photo of the valve in question, for anyone who doesn't know what they are.