(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 7 of 7

Thread: Repressurizing Heating System

  1. #1
    DIY Senior Member chefwong's Avatar
    Join Date
    Jun 2006
    Location
    District of Columbia
    Posts
    710

    Default Repressurizing Heating System

    Hot Water Heating System.
    I've set the stat to 90 degrees - water got hot, pump has been running for about a 1 hr so far.
    When I bleed the lower basement radiators, I am getting water.
    No water on the 1st and 2nd level when I attempt to bleed air.

    Lower basement baseboard are not warm yet.
    When I feel the outgoing / return pipes off the unit and the pump...it's all nice and toasty.

    Any advice.

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,434

    Default

    Open the fill valve then open one of the upper floor's bleeder valve until you get water out. Repeat at the other bleeders upstairs. Once you've got all the air out, you should get circulation. It doesn't take much air to block flow when it needs to go up. Once almost all of the air is out, the air extraction system should pull the rest out as it circulates around as microbubbles.

    The pump in most systems doesn't have a lot of head - it takes the full system being full of water with some of it pushing back down to help it flow all the way around. then, since it is a closed system, the low powered pump can keep it flowing.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  3. #3
    DIY Senior Member chefwong's Avatar
    Join Date
    Jun 2006
    Location
    District of Columbia
    Posts
    710

    Default

    Are you saying open all the bleeders and leave them open till water comes out...

    I went around leaving some bleeders open for about 15 minutes....and no dice.
    It's circulating on the *main pipe* as I can feel it hot on the *loop and then the return to the pump*.

    It's just not circulating on the baseboards.
    Even the lowest /closest runs *basement*, water is good coming out the bleeder but they are not getting warm yet.
    I suspect the basement is not getting warm cause the entire *system* is not fully pressureized ?

  4. #4
    In the Trades Tom Sawyer's Avatar
    Join Date
    Nov 2010
    Location
    Maine
    Posts
    2,946

    Default

    Not enough water pressure. Your fill valve is probably bad.
    [B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]

  5. #5
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,434

    Default

    If you can't get water out of the bleeders, you're not introducing water into the system for some reason. If you have an autofill valve, it may be gunked up, or you have an in-line valve shutting it off (not a bad idea, as once the system is full, it should not be needed to keep it topped off and can mask a slow leak). If things are working right, you should hear air escaping when you open it, and eventually, get water out. You will not get good circulation until you get (nearly) all of the air out. The air extraction devices can only deal with a little air for the most part, not huge amounts.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  6. #6
    DIY Senior Member chefwong's Avatar
    Join Date
    Jun 2006
    Location
    District of Columbia
    Posts
    710

    Default

    Thank you all.

    I did not even check to bleed air prior to restarting today

    I gave a little nudge to the fill valve and some water appeared to flow *heard it flowing*.
    I then cranked up the tstat so it would engage and just went around bleeding air. Amazingly, water was bleeding out almost immediate and I just simply went around bleeding air on all the baseboards.

    The pump was running for another 2+ hrs yesterday before I shut the system down...I did not reattempt to bleed air before I went to sleep.


    BTW, how often or not is one supposed to *empty the water* out of the overflow tank that's on the return side.
    I probably do that that every other year.....
    Last edited by chefwong; 11-08-2012 at 12:12 PM.

  7. #7
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,434

    Default

    Quote Originally Posted by chefwong View Post
    BTW, how often or not is one supposed to *empty the water* out of the overflow tank that's on the return side.
    I probably do that that every other year.....
    There are a couple of types of expansion tanks. The preferred one is a bladder tank, and on it, you never drain it until it fails. The older styles tend to absorb all of the air and stop functioning, assumig you have an air extraction device. On those, since the air is in contact with the water, a little bit gets disolved as the water goes by, gets extracted, and eventually, stops functioning. Also, since air has oxygen in it, you are constantly adding that to the water which means things can rust. Pure water with no disolved air will not generate rust. When you add water to a system, you're also adding air, and until that gets used up (by rusting things) or extracted (the better choice!) rust continues to accumulate...IOW, you do not want to be adding water to the system or draining things out (which may mean you have to add some water as well). If you're not using a bladder tank, you might want to consider replacing what you have with one properly sized for your system.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

Similar Threads

  1. Which heating system is best for my use?
    By rick.a in forum HVAC Heating & Cooling
    Replies: 4
    Last Post: 07-10-2010, 05:05 PM
  2. Heating System
    By sgrd0q in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 10-16-2008, 01:30 PM
  3. Monoflow heating system/ Air in system
    By emattera in forum HVAC Heating & Cooling
    Replies: 16
    Last Post: 02-11-2008, 10:52 PM
  4. Mapping heating system
    By bmccabe in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 5
    Last Post: 12-06-2007, 05:09 AM
  5. air in pipes - well or heating system?
    By allycat in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 02-25-2005, 08:59 PM

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
  •