What is causing air in house water lines?

[Travelover]

I've got a weird problem. Suddenly I have air in the water lines in my house, especially the hot water lines.

I have a well and rather than a bladder tank, it has an air control valve tank which means it keeps a specified amount of air in the pressure storage tank at all times and bleeds off any excess air via a float control inside the tank. Air is introduced into the tank via a couple of check valves in the drop pipe. The tank seems to be operating properly as I can draw a lot of water off the tank before the pump kicks on. It seems like air and water should be separated within the tank and not feed into the lines.

I'm wondering if a second possibility might be a broken dip tube in the water heater. If air collected in the top of the water heater and the dip tube was broken off air could enter the outlet. The usual symptoms of a broken dip tube are not there - it gives plenty of hot water at a constant temperature and no plastic bits are in the faucet aerators. This also wouldn't explain occasion air in the cold water pipes.

Anyone had a similar issue?

 

[JasperFrank]

Do you have a water softener system?

 

[Travelover]

Do you have a water softener system?

No.

 

[BigGG]

I've got a weird problem. Suddenly I have air in the water lines in my house, especially the hot water lines.

I have a well and rather than a bladder tank, it has an air control valve tank which means it keeps a specified amount of air in the pressure storage tank at all times and bleeds off any excess air via a float control inside the tank. Air is introduced into the tank via a couple of check valves in the drop pipe. The tank seems to be operating properly as I can draw a lot of water off the tank before the pump kicks on. It seems like air and water should be separated within the tank and not feed into the lines.

I'm wondering if a second possibility might be a broken dip tube in the water heater. If air collected in the top of the water heater and the dip tube was broken off air could enter the outlet. The usual symptoms of a broken dip tube are not there - it gives plenty of hot water at a constant temperature and no plastic bits are in the faucet aerators. This also wouldn't explain occasion air in the cold water pipes.

Anyone had a similar issue?

This is a submersible pump, correct? Just a note, there are two different type air volume controls in the referenced article; the first is a diaphragm admittance type used with jet pumps. The other, which you have, is a bleed type first used with piston pumps that had a small air pump which pumped air into the pump discharge, thus the need to bleed off the excess.

I'd say your AV valve has failed. You can sort of test it; turn the pump off and depressurize your system by draining it as close to the pump as practical. Let the air out also. You want to leave water in as much of the system as you can. Then turn the pump on and pressurize the system. If should operate normally for at least a few cycles. If it does before the air shows up again, your AV control is bad. Could be plugged. Be aware that these valves must be oriented correctly to function right.

 

[zzvyb6]

The water level in your well may have lowered to the point where the pump is sucking in air. I had to lower my pump 3 feet to get rid of it when a new subdivision tapped into the water vein.

 

[Travelover]

This is a submersible pump, correct? ......

I'd say your AV valve has failed........

Yes, it is a submersible pump, 130 or so feet in the ground.

Re the air control valve, are you thinking that the tank has too much air and not enough water in it?

 

[Travelover]

The water level in your well may have lowered to the point where the pump is sucking in air. I had to lower my pump 3 feet to get rid of it when a new subdivision tapped into the water vein.

I wondered about this.
If the pump was sucking in air, wouldn't the air be separated out within the tank? It is designed to have air over water inside the tank and bleed off excess air.

Also why is the air predominantly in the hot water side?

 

[RayIN]

Water absorbs air. That is a common occurrence in RV water heaters. The tank is designed so there is about a inch of air space, when the air is absorbed by water, the pressure relieve valve dribbles due to over-pressure in the tank.
So, my EWAG is the air is absorbed by the water and shows up at your hot faucets because of the heating and convection.
I suggest turn on your well pump and WH heat source, relieve water pressure. Then 'burp' the over-pressure valve, if water comes out my theory is wrong.

 

[steve tym]

Do you have a new water heater?

 

[not2old]

I also have air in my hot water after not using hot water for several hours or longer. After being away for a week it doesn't seem to have any more air than after a day. Mine is complicated by having my geothermal furnace connected to the heater. The heater is over 15 years old but appears to be working fine. There are no leaks that I've been able to find. I've adopted the idea of not worrying about it until something quits working and it's been like this for seven or eight years or more.