(206) 949-5683, Top Rated Plumber, Seattle
Page 1 of 2 12 LastLast
Results 1 to 15 of 19

Thread: Air in hot water line

  1. #1

    Default Air in hot water line

    When ever you turn on the hot water it spits out of the faucet for a couple of seconds, but it comes out with a lot of force, it will knock whatever your holding on to out of your hands. What is going on here?

  2. #2
    Plumber Cass's Avatar
    Join Date
    Nov 2005
    Location
    Ohio
    Posts
    5,984

    Default

    do you have a well or is it city water?

  3. #3

    Default

    I have a well

  4. #4

    Default

    I've never seen this phenomenon in a water heater, though it does happen once in a while. However, it is common in boiler systems. Older boiler systems had an expansion tank which was about half full of air, and you had to watch the glass guage on the end of the tank to see that the level of water in the tank remained at acceptable levels because the boiler would "make" air. Heating and reheating the water would release trapped air.

    These days, it's not uncommon to use an expansion tank on a water heater, especially when there is a water pressure reducing valve on the incoming water. But this probably wouldn't solve your problem because these are the bladder-type tanks, and not designed to hold air in the water chamber. You might be able to add an air relief valve similar to those used on boilers, though it might take a little repiping on the hot water side of the heater to trap the air.



    The vent would go in the hot water line, but the line should be horizontal, then drop down before going back up to the system, so that air in the line above the heater couldn't get into the rest of the system.

    This assumes that it is indeed air and not steam, that your relief valve is functioning correctly, and so on. One assumes that the heater is separating air from water whenever it's heating, but it tends to build up during the night when the hot water isn't being used.

    In a boiler, air is bad because it can lead to rusting and failure, and I don't know if it would be the same in a water heater, but I think the problem should be addressed, if only to prevent broken water glasses and heart attacks.

  5. #5

    Default air in hot water line

    Hi,
    I'm having the same problem. I have a gas water heater, and the air is only coming out of the hot water taps. It's worse in the mornings, but does happen all day. I am also on a well with a pressure tank . The problems started when we replaced our hot water tank. We went from a 30 gallon tank to 40 gallons. Is there maybe something that needs to be adjusted on the pressure tank?
    I've asked lots of plumbers as well as googling this problem, and no one seems to have an answer.

  6. #6
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,395

    Default

    Pumping water can entrap air depending on the conditions. If you fill a glass with cold water and let it set for say an hour or so undisturbed, do you get air bubbles on the sides of the glass?

    How you'd get rid of it in the WH, I don't know. Heating it will drive it out, and it would rise to the surface, which gives you the burst of air when drawing hot water.

    I'd also look at all of the pipes and connections to verify there isn't a small leak. It could suck air rather than leak water, depending, too.

    It could be bacterial or algae too, but those are less likely. Their biological process can give off some gas. Does the gas have any smell? Neither CO2 or O2 have any odor.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  7. #7

    Default

    We have had leaks in the past that have been fixed. There is no odor from the air. I'll have to give the water in the glass experiment a try. What will that tell me?

  8. #8
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,395

    Default

    That you've got trapped air, and if it weren't for the heating, you'd get spurts out of the cold as well. This could mean that the pump is not far enough into the well or that the well isn't producing fast enough anymore, so it is cavitating and getting air in the lines. Pumps aren't my strong point. See what other comments you get.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  9. #9

    Default

    okay, I did the experiment, and there's no bubbles in the glass, so that's a good thing. I didn't think it would be a well/pump problem.

  10. #10

    Default

    Do you have an expansion tank by your water heater? If you do which side is it on, hot or cold?

  11. #11

    Default

    do you mean a pressure tank? It's actually right across the isle from the front of the tank, not right next to it. And it's dead center between the hot and cold.

  12. #12
    DIY Senior Member Marlin336's Avatar
    Join Date
    Aug 2007
    Location
    Suffolk, NY
    Posts
    187

    Default

    Quote Originally Posted by pking View Post
    do you mean a pressure tank? It's actually right across the isle from the front of the tank, not right next to it. And it's dead center between the hot and cold.
    It can't be on both sides. It's either tied into the hot side or the cold side. It should be tied into the cold side. I saw the same thing happen a few weeks ago. Someone put the tank on the hot side and they kept getting air in the faucets.

  13. #13

    Default

    I checked and it's tied into the cold side.

  14. #14

    Default air build up in hot water plumbing

    I have same issue with no resolution - Turn on hot water and 3 seconds of water followed by 20 seconds of air. System is at cottage so usually one week without use. Had water heater replaced (electric) and now have this issue - hot water only. Cold side is ok. On a well but no change to it. No expansion tank or other things different. Never had problen before new water heater. Installer at a loss - has never seen issue. Need some help. Thanks.

  15. #15
    DIY Junior Member
    Join Date
    May 2009
    Location
    Muskoka, Canada
    Posts
    2

    Default air in hot water lines

    Hi:

    Same problem. Some time ago I came across a post or two from Alberta, where methane gas in water wells is apparently a problem. they suggested installing a Honeywell Braukmann valve in the hot water line. I did that, and the problem went away for quite a while...but now it's back, and I am getting a bit tense about it again (well my wife is). Still, I'd like to know if there is any maintenance you need to do with these valves. any ideas? Pump seems to sucking air/water mix at startup, then settles down to pure water, it seems - different sucking noise. Well is actually higher than pump - worked fine w/o a foot valve - go figger, so priming is definitely not an issue. Incoming water line is HEAVY duty, through sand, and part of it is under the deck, etc.....don't want to go there. Otherwise system works fine. Water is acidic and contains much iron = welcome to the Canadian Shield, and we are on our fourth (count 'em) fourth, water heater in 5 years - but this one seems to be working better than the others, in that the hot water is not yet brown...though I suspect it will do so in time as the anode is eaten up and the water attacks the tank.

    Does this wound like a tale of woe or what? Any advice on the Braukmann valve will be welcome.

    thanks
    Henk

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •