Air in well water

Bob Gagnon plumbing and heating · August 2010

I have a customer who had their well tank changed and has had a lot of air in their water ever since, he has to run his faucets for two to three minutes in the morning before he gets water. The pump is down in the well, he has never had a problem there or with having enough water in the well, this has only happened after changing his diaphragm tank in the basement. Living in the city I don't have much experience dealing with wells, the only thing I can see different here is the relief valve is on the incoming water supply, not the tank, put it's all pressurized so I don't see how the air could get in there. There is no sign of leaking water anywhere.

Thanks, Bob Gagnon

Mark Eatherton · August 2010

Well,well, well....

Hi Bob,

There are as many different designs of potable well systems as there are hydronic heating systems. There are open, drain back systems and closed systems.

In one of my cabins, I have a diaphragm-less tank that has a float operated bleed valve mid way up the tank. The water comes in and out of the bottom. The compression cushion is the upper part of the tank. When the pump shuts off based on pressure, a check valve between the pump and the tank keeps the water in the tank, but the pipe from the well to the check valve drains back down into the well. Occasionally, the float valve malfunctions, and it lets the excess air come out of the tank, and into the water. Pretty frustrating being in the shower, getting all lathered up, and suddenly, there is mostly air coming out of the shower head.

If the old tank was this float operated style of tank, and it was replaced with a diaphragm type of tank, therein lies the problem. The air from the drain back operation is being forced into the distribution system. You may need to install a Micro Bubble Resorber on the outlet of the tank.

My neighbors well was a conventional, non drain back diaphragm type tank, and he had a gas issue, so I installed a microbubble resorber and got rid of the problem. He, being the curious type, decided to see if the gas that was being collected and expelled, was flammable. He struck a Bic lighter next to the head of the MBR while it was expelling gas, and singed the hair completely off his arm. Hydrogen?

Now he wants to figure out a way to capture and store the gas and use it for heating his home. I cautioned him against it.

HTH

ME

Rod · August 2010

Water Wells

Hi Bob- I'm not a well expert but since we have two houses on well water have had some experience with them over the years. Presuming the pump is building pressure and cycling okay, rather than air, it sounds to me like the water is flowing back into the well. I'm presuming you have a pressure gauge on the line. After the pump shuts off and the taps aren't opened does the line hold pressure? Also listen on the line for any sounds like a "glub, glub, glub" which means the water is retreating back into the well. Most submersible pumps have a check valve (foot valve) built in. It maybe an indication that the foot valve is going bad. On my wells I put a check valve, as a backup, close to the well head before the any of the other equipment (pressure tanks etc.)

I'm wondering about the "relief valve" you mentioned. Did the old air tank have a bladder? I've used a bladder tank now for years but on my old air tanks (before bladders) they had some sort of valve that allowed air into the system so the air cushion in the tank would be "recharged" . I guess it was sort of like a vacuum breaker on a 1 pipe TRV. Since it's not necessary with a bladder tank I'd get rid of it and also add the backup check valve.

- Rod

Edit: I posted and then saw that ME has given you a better explanation and fix. I hadn't thought of a Micro Bubble Resorber but I can see where it's a good idea and will add one next season when I put the pump back in for the summer. Thanks ME! - Rod

Charlie from wmass · August 2010

Some systems have built in bleeders

Bob was the old tank a diaphragm tank or a plain galvanized tank? The bleeders were put in to prevent the shallow lines from freezing by draining back to the well. With a galvanized tank it simply built up in there and was bled off by by an air volume control,. I am betting on a split in the line between the pump and the tank. The one in the well can be found often by listening at the well head. If the check valve at the tank is good then the pressure will not drop even if the line is broken. Air and then dirt will start showing up if it is under ground between the house and well. Cutting the line between the check valve and well will let you know if the water is flowing back, just not tel you were it is flow to.

Go and check it by the numbers starting with precharge pressure at the tank and trace it back. I do a lot of well work, we stock several sizes of well pumps and even have a power puller for well pumps.

Air in well water

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