# Air pump on pressure tank?



## bob_cntrctr (Jan 30, 2008)

Gentlemen,

Can anyone imagine what this is about?

I'm looking at a unit here - on well & septic. Two pressure tanks installed in parallel. The larger of the two has a small electric air pump permanently connected to the top of the tank, and it's wired into the pressure switch so that every time the well pump comes on, so does this little air pump.

Never seen anything like this before. Can anyone confirm that this is something normal and with a purpse? Or am I calling the plumber to fix someone's mess?

Thanks.

*Update:* - I cannot find an air inlet nipple anywhere on the tank that one might use to adjust the precharge.


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## KillerToiletSpider (May 27, 2007)

It could be an older tank that does not have a diaphragm in it to sustain the pressure, and instead relies on the pump to do that instead.


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## paul100 (Dec 7, 2008)

Are you sure it is an air pump and not a chemical feed pump. Chemical feed pump would be used to pump chlorine and other chemicals into the water every time the main water pump kicked on.


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## bob_cntrctr (Jan 30, 2008)

KillerToiletSpider said:


> It could be an older tank that does not have a diaphragm in it to sustain the pressure, and instead relies on the pump to do that instead.


Thanks for the suggestion - but I think it's not very old. It's a fiber-wound Well Mate tank, about 100-gallons.


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## bob_cntrctr (Jan 30, 2008)

paul100 said:


> Are you sure it is an air pump and not a chemical feed pump. Chemical feed pump would be used to pump chlorine and other chemicals into the water every time the main water pump kicked on.


Yes, I suppose that's possible. There is no hose for drawing in a treatment chemical, nor a container for such, only a hose from the pump to the top of the cyclinder - but I suppose it could have just been removed and the pump left there.

Also, it has no metering for delivering any set amount of chemicals - just a pressure meter, which reads approximately the line-pressure, and it runs the whole time the well pump is on.

*Update:* - I cannot find an air inlet nipple anywhere on the tank that one might use to adjust the precharge.


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## Oconomowoc (Oct 13, 2011)

The tank with the pump has no bladder and the purpose of the pump is to introduce air and reduce the smell - like sulfer etc. The next tank has a bladder.

In the old days they were called "air over water" tanks and they were great because it would help reduce the rotten eggs smell.

There's a good chance the original house had one simple pressure tank. Then the HO couldn't take the smell so a plumber put in the extra tank in to get rid of it.


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## Oconomowoc (Oct 13, 2011)

Whatever you do don't take out the tank with the pump or you will have a very pissed off home owner. The sulfer smell is probably really bad and the second that tank is removed it will come out the faucets. Lol

Remember, a bladder tank has no "air to water" direct connection. So by itself the smell is simply transfered in the water until it bleeds out the faucets.

They do work very well and it's dependable.


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## bob_cntrctr (Jan 30, 2008)

Ding! Ding! Ding!

I do believe you nailed it. Searched for those terms and found this:

http://www.wellmatetanks.com/wellma...p-series-traditional-air-over-water-tanks.htm

That's exactly what it is. So, no, not a sketchy installation I have to get corrected by the plumber. But don't worry - there'll be other work for him on this one.

Thanks a bunch.


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## Oconomowoc (Oct 13, 2011)

You're welcome


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## Oconomowoc (Oct 13, 2011)

FYI: It's worth mentioning to the home owner that they should have the water tested. Sulfur is one thing but sulfur bacteria is another. 

A system like this can hide or mask a much more severe problem. A water test done by a laboratory is a smart precaution and it's a kind thing to mention.


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## bob_cntrctr (Jan 30, 2008)

Thanks for the additional info.

The "homeowner" is the rental group I work for. This house was recently purchased to be turned into a rental. My job is to identify what should be done to make everything up to snuff before it's rented out, then manage the property (so any grief I get from tenants about deficiencies is my own damn fault.....). I try to figure out as much as I can before calling the specialty trades so I know what I'm talking about. 

So a standard bacteriological test was done for the purchase. I'll check if that covered sulfur bacteria.

Then I'll be looking up how to go about adjusting the pre-charge on this thing so we can dial down the system pressure. Previous owners had it jacked up to 50psi cut-in and 75psi cut-out! No wonder the toilet inlet valves were leaking.

Anyway - thanks again.


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## Oconomowoc (Oct 13, 2011)

It's normal for those to run up to 75. Don't change anything! You'll phuc it up!

75 psi are not causing a leak, they can handle it. 80 psi is Max in Wisconsin but to be at 75 is normal for an aeration system. 

60 is average for NORMAL systems but NOT for that. We're only talking 15 pounds. 

Polish it with a rag and walk away. Lol


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## Oconomowoc (Oct 13, 2011)

Spend $8 and put Fluidmaster 400A's in the toilet tanks. Done!


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## bob_cntrctr (Jan 30, 2008)

Oconomowoc said:


> It's normal for those to run up to 75. Don't change anything! You'll phuc it up!
> 
> 60 is average for NORMAL systems but NOT for that.


So now I'm curious, for my own education - why the higher pressure for an air-injection system? And how would reducing to 60 mess it up?

And...

double-checking the Well Mate site

www.wellmatetanks.com/wellmate-fiberglass-tanks/hp-series-traditional-air-over-water-tanks.htm

and

http://www.wellmate.com/en-US/produ...atic-air-water-tanks/hp-quick-connect-series/

You couldn't know this for your previous replies, obviously, but the specs for this tank say max operating pressure = 75psi.

So I'm gonna hafta turn it down - doesn't seem reasonable operating everyday at max spec, with zero room for thermal expansion spikes.

Update: I spoke with Well Mate. They confirm - under no circumstances should this tank be operated at 75psi.


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## Oconomowoc (Oct 13, 2011)

Well, the limit is 75 and that where you are at so it's not an issue. Historically aeration systems are run at the max. If you adjust it make sure you know what you are doing. It's been working just fine because it's set-up to run like that.

Anyhow, the tank is not the limit. What I mean is, operating pressure is different than engineered pressure capacity. Lots, and I.mean lots of them are at 75.

If the pressure exceeds 80 psi the system has a relief valve that trips and this is to protect the system from pressure.

Do what you want of course it's your baby.


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## bob_cntrctr (Jan 30, 2008)

Well, much appreciate the input and someone to discuss it with, but it sounds like it's not as sorted out as I thought.

Manufacturer says don't do that. This being a rental, if something were to happen, "I read on the internet..." wouldn't be much of a defense. 

So it looks like a specialty trade will be getting work on this after all. I've got the water treatment system guys coming today to sort it out. Important thing was to determine that, yes, there are questions justifying the visit, not just my ignorance.

Thanks agaain.


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