How to drain air from hydronic loop

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  #1  
Old 10-12-19, 03:22 PM
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How to drain air from hydronic loop

I noticed the hvac tech who came out last time was able to drain the air out of the lines without having to unscrew every vent tee in the house. I took a picture of where I think he hooked a hose up to. Iím not even sure what the fitting is called. Anyway it will come in handy in case theres another brake in my line. Fyi, Iím new to this so please help and explain the process. Anyway heres a few pics of what iím dealing with. The first picture is the fitting Iím talking about. I dont know why my pics are comming in sideways? They are rightside up when I load them..

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Last edited by PJmax; 10-12-19 at 04:58 PM. Reason: reoriented/enlarged/enhanced pictures
  #2  
Old 10-14-19, 05:01 AM
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I start with the fact air bubbles rise in water and install auto vents at highest point in each loop. Never have to vent system.

Think venting at lowest level boiler is wishful thinking. Often see pictures on this site of cheap vents on air scoops near boiler coated with crud from leaks.

Here is trouble free vent that can be opened for service.
https://www.supplyhouse.com/Watts-05...Vent-3679000-p

Auto vents with sealed cans are the worst. A red gasket in tire valve type seal goes after a couple of years then leaks.

https://www.supplyhouse.com/Jacobus-...xoCg-8QAvD_BwE
 
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Last edited by doughess; 10-14-19 at 05:24 AM.
  #3  
Old 10-21-19, 05:20 AM
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Ssssss

Not sure it appears that a servicable watts auto vent is in one of the pics. Also pictured is a fitting that was used by the last plumber to air everything out in one place. He hooked what looked like a hose with a guage to that fitting and in 5 mins everything was aired out. Would be nice to know exactly what he did to air the lines out.
 
  #4  
Old 10-24-19, 07:37 AM
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How does Doylee4693 know that ďeverything was aired outĒ when vented at low level in system?
That is wishful thinking in post #2..

Even if auto vent on air scoop in picture is working (has he confirm it vents?) there is no way to know if that vented air at highest point.

Do not equate "professional" with doing it right. Became a DIYer after professionals got it wrong. Now do my own reality checks.
 
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  #5  
Old 10-25-19, 12:34 PM
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D,
To answer your initial question that yellow valve is a shutoff purge valve combo. What the tech did was shut off power to your boiler and shut that yellow valve off to stop the water from back feeding from the boiler and then attach a hose to the drain part. Open that valve and drain water and air until water runs clear then shut off your drain valve, open the ball valve and turn on the boiler and check the system.

Your system should be bled under high pressure but the way your system is fed it's difficult to achieve this. How did you get air in the system in the first place.

Your feed system is adjustable and when bleeding should be set to 25-28 psi while bleeding and then reset to about 20 when done.

https://www.supplyhouse.com/Amtrol-1...lume-4910000-p

This is something like what you have only your is completely sweat but does the same thing. You can read about it on this this sight below.

https://www.supplyhouse.com/Webstone...nge-with-Drain

Don't worry about the high vents. They are useless on residential systems and can cause more problems than you have now.

Hope this helps a little.
 

Last edited by spott; 10-25-19 at 01:04 PM.
  #6  
Old 10-26-19, 09:21 AM
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For many years the general US practice for residential hydronic pressure has been 12 psig. In homes with higher system elevations, pressure is raised as needed.

Manufactures of pressure regulators and expansion tanks ship them pre-set for 12 psig so installers do not have to adjust every one, but some will have to be adjusted

Spott may believe in venting at 25-28 psi, but it is not common practice and may cause significant problems.

Spott stating resetting pressure to 20 psi is contrary to basic HVAC engineering practices. But then he may never have learned them.

Then there are words about high vents being useless. If Spott wants to think vents are useless and bubbles sink in water DIY readers can use that a validity check of his words.

For reference see: https://www.techstreet.com/ashrae/ashrae_handbook.html
 

Last edited by doughess; 10-26-19 at 09:45 AM.
  #7  
Old 10-26-19, 02:35 PM
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doughess,
Welcome to what looks like another long season.

If you go to my post and click on the Amtrol link and read the install portion and see their recommendations for settings. Since they seem to agree with my recommendation, apparently they have not learned the HVAC engineering practices either.

As for the venting it's just a personal choice, like your sarcastic remarks.

Grow up.
 
  #8  
Old 10-27-19, 08:13 AM
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Amtrol makes tanks for all kinds of applications, not just hyrdronic.

Just entered my home system data in Amtrol's hydronic tank sizing site. Amtrol answer was wrong.

To maintain stable pressure I use a different size tank than Amtrol recommended

Try to make HVAC system decisions based on established principles and hard data when available.

Amtrol and site are too limited to be reliable. As Spott posted "apparently they have not learned the HVAC engineering practices either."

Venting is about removing air. My choice is way to remove all of it with auto vents. Have 13 of them on my system so never have to manually vent .... so I can grow old in comfort.

DIY readers can judge the data in this thread.
 

Last edited by doughess; 10-27-19 at 08:34 AM.
  #9  
Old 01-17-20, 08:23 AM
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Ok guys im back again and my valve that lets water from the street in has begun to leak. This is how I plan on bleeding the system. I would shut off main water supply, shut down boiler, remove the leaking water valve inlet . Then I would turn water back on from street, open new valve and make sure itís water tight. Then from there while leaving the boiler off I would refill the boiler and the water to the vents. Turn off the large handle on the yellow Ball Drain thats pictured, hook a hose to the end of the fitting and turn on the smaller yellow handle and let that water run until it doesnt ďburpĒ anymore. Shut the small handle and turn the large handle back on and then turn the boiler back on. Is this process correct? What do I do if there is still air in the system after i turn the boiler on? Thanks
 

Last edited by Doylee4693; 01-17-20 at 08:38 AM.
  #10  
Old 01-17-20, 11:39 AM
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With each section of baseboard having a vent tee, it makes me wonder if the system is of the diverter tee type. if it is, purging at the boiler will do little good.
 
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Old 01-17-20, 02:16 PM
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I noticed the hvac tech who came here last did it and it ran like a charm until I stupidly decided to fiddle with the gate valve thinking that turning it off would save my house from a frozen pipe burst that I seem to get every year when the temps dip into teens and single digits. Is there anymore pics I could take to clear things up a little more?
 
  #12  
Old 01-17-20, 07:18 PM
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If purging near the boiler worked well, the chances of you having a diverter tee system are pretty slim. An easy way to tell is look at the pipe goes up thru the floor to the baseboard. If it goes up with an elbow, it it NOT a diverter tee system. On the other hand, if the pipe feeding the baseboard comes off a tee, you likely do have a diverter tee system.
 
 

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