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scttcrssmn
Air in water line
scttcrssmn

Plumber replaced shallow well pump in basement with submersible in 50' well. Also replaced anode rod in hot water tank. Ever since, I get air purging through line after short periods of not using water. I have taken a picture of pressure gauge before going to bed, then again six hours later in morning and there is not even a pound of pressure lost. Did this twice to be sure. Have put water softener on bypass before bed, purged any air from lines, then turned on water in morning while still on bypass and got plenty of air. So I think that eliminates water softener as source. Have pushed top vent on Big Blue filter and no air purges there. There is no evidence of any leaks anywhere. No leaking around anode rod fitting or hot water tank at all. And I'm not positive, but air seems to be mostly or all from hot supply. Pressure is set up at 30/50. Plumber says he thinks the new pump pushes water at such high velocity that it is seperating air from water. Problem is now two months old and no resolution in sight. Suggestions, please.

bill
Re: Air in water line
bill

It could be cavitation due to a very power full pump. Go and do research on cavitation. to see what i am talking about.

Bill

KD5AWS
Re: Air in water line
KD5AWS

Yes cavitation can cause air issues in the pump system but it is caused by a restricted suction screen on the intake of the submersible pump. Trash in the well can cause this.

Another issue could be that any air charge devices used with the old shallow well jet system need to be removed from the drop pipe to the pump within the well. Query, was the pressure tank changed at the same time as the pump? If a captive air tank was installed changing out a standard tank that requires an air charge at the start of the pump cycle, that could be causing issues.

Another problem could be leaking coupling on the drop pipe in the well. What type of drop pipe was used? galvanized steel pipe, threaded Sch. 80 or 120 PVC pipe? What type of couplings? Galvanized, Brass, Stainless Steel? What type of pipe sealant? Teflon tape? Teflon Paste?

If the screen is not blocked, the pump also could be too big for the well, i.e. the gpm of the pump is higher than the specific capacity gpm of the well. If the pump is 5 GPM and the specific capacity of the well is 4 GPM, you're sucking air.

This shouldn't be hard to figure out but it sounds like the pump may have to be pulled again and eliminate all other possible causes.

Charlie Johnson
Modern Well Service & Supply
Plainview, TX
TDLR Pump Installer 58554KPT

scttcrssmn
Re: Air in water line
scttcrssmn

Charlie,

Thanks for reply. No air charge devices in line. Bladder tank was not replaced, it is fairly new and maintains good pressure. I believe the existing PVC drop pipe was used, can't give you specifics about coupling, etc. because I was not present. If these were a problem, wouldn't I see pressure change over a six hour test period? I mentioned this in the original post.

How do I determine the specific capicity of the well? I woild like tk know more about this as it could very well be the pump capacity is higher than the well.

Thanks
Scott

scttcrssmn
Re: Air in water line
scttcrssmn

Bill and Charlie,

Thanks for reply. No air charge devices in line. Bladder tank was not replaced, it is fairly new and maintains good pressure. I believe the existing PVC drop pipe was used, can't give you specifics about coupling, etc. because I was not present. If these were a problem, wouldn't I see pressure change over a six hour test period? I mentioned this in the original post.

How do I determine the specific capicity of the well? I woild like tk know more about this as it could very well be the pump capacity is higher than the well.

Thanks
Scott

HoustonRemodeler
Re: Air in water line
HoustonRemodeler

What about adding an air scoop or air separator ?

keith3267
Re: Air in water line
keith3267

I think KD5AWS pretty much hit the nail on the head. The only things I would add are the possibility of a crack in the drop pipe or a leak at one of its fittings. The crack or leak would have to be above the water line. What happens is that when the pump shuts off, all the water in the line between the check valve in front of the water tank and the crack will leak back into the well. When the pumps starts the next time, all the air that is now in the pipe will be pumped into the pressure tank.

Had this happen to me once. BTW, the reason that it si more noticeable on the hot water is that any air that gets into the supply line when the water is turned off will rise to the highest point in the system, which is usually the top of the water heater. You get it in the cold water faucets when the level in the pressure tanks drops to the minimum setting.

scttcrssmn
Re: Air in water line
scttcrssmn

KD5AWS how do I determine capicity of well to compare to pump capacity?

Keith3267, plumber said something that lead me to believe he removed check valve for anspecific reason. Can you think why he would do that? Water line is typically only about 8'below grade. A question, if it was leaking back into the well, wouldn't I see even a slight change in pressure gauge overnight?

HoustonRemodeler - what's an air scoop or air seperator? Installed where in the line, and how doesnit work?

Sorry guys, homeowner, not a plumber, and I feel abandoned by the original plumber. Need to come up to speed like I should have done before install so I can hire someone to fix and know some of the options. I dont want to spend another pile of $$ and not get problem resolved.

keith3267
Re: Air in water line
keith3267

You have a check valve on the input side of your tank. If you didn't, the tank would not hold pressure. The check valve is a brass piece about 4-5" long and about 2" in diameter. It probably has the pressure gauge attached to it.

The submersible pump should also have a check valve on its output. If all the pipes are sealed so no air can get in, then if the check valve is not on top of the pump, I don't think it will affect the system. The water level may drop in the pipe, but there will be a pure vacuum in any pipe above the water line. Since your water table is only 8' below the ground, you would not reach this condition. This would only occur if the water table was more than 32' below the ground. Note, its the water table and not the depth of the pump that matters.

If the check valve is missing from the pump, it will aggravate the condition created by a crack or leaking fitting on the down pipe because it will let the water drop further and let in more air. But there first has to be a leak.

Edit: remove the cap from the top of the casing of the well and then turn on the water to get the pump to come on. If there is a leak or crack, you may be able to see the water spray with a flashlight looking down the casing.

scttcrssmn
Re: Air in water line
scttcrssmn

Thanks keith3267, I will look down well for this over the weekend.

scttcrssmn
Re: Air in water line
scttcrssmn

Finally talked to the plumber and gently gave him all of the possibilities you guys have provided. Told me the reason he hasn't contacted me in three months is because he's doing "research". Said the pump was right-sized for well, that there are no leaks in well, and that all the iron in my water has likely caused the water flow to be slow and the pump gets ahead of replenishment. Said I need to get well driller to ream it out and maybe deepen it. So that's it, sounds like my problem not his. And I wonder who to turn to after the well driller takes my money and I still have air in the house lines.

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