Wondering if I can purge our baseboard heating system or not...

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  #1  
Old 01-12-19, 10:21 AM
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Wondering if I can purge our baseboard heating system or not...

Hello, everyone!

I don't have much experience with baseboard water heating systems being from a much warmer climate. We have a significant amount of air in our system and were unsuccessful getting the air out using the bleeder valves. (I should say that one unit had a lot of air in it and we did remove that air. However, it now seems like multiple units are now gurgling but no air will come out of them. The column of air moves in a predictable pattern but air will only come out of the aforementioned unit.)

I then looked for Youtube videos on how to purge our system. It looks very straightforward but I am not sure that our system can be purged. All videos show a spigot above the zone shutoff valve thus making a purge possible. We have one spigot at the bottom of the system but I feel that it will only allow one to drain the system and not purge it.

Any help or advice would be much appreciated as pros in the area are busy with more pressing matters. We are warm, just annoyed. Thanks!

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  #2  
Old 01-12-19, 10:46 AM
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C,
I do not see any purge valves above your pumps which would be used to bleed the air from your system.

There are different system designs and not all can be purged from the return line. You mentioned bleeding from air vents. Are those individual vents on the emitters (baseboards rads).

What type of emitters do you have and how are they fed. You have 2 pumps so I'm assuming you have 2 zones with 2 thermostats.

In order to bleed your zones from the basement return line your piping needs to be a series loop system which means the water flows from one baseboard to another and another and back to the boiler using the emitters as part of the loop.

If your emitters are individually fed from the main supply with special fittings called monoflo or scoop tees they must be individually bled from the vent on the emitters and can be very time consuming and tricky.

Pics and more info would be helpful.

Hope this helps a little.
 
  #3  
Old 01-12-19, 12:57 PM
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When you open the bleed valves on the radiators, does water come out?

Gently lift the end of the baseboard radiator innards where the bleed valve is If there is any give then prop that end up using some small blocks of wood or other small solid objects.

Gently depress the end of the baseboard innards without the bleed valve. If there is any give then weight it down.

Try increasing the system pressure a few PSI by admitting a little more water into the system. If nothing at all comes out of the bleed valve then the system pressure is too low.

Now try bleeding the radiators again.

It might be necessary to wait a day, add more water to the system. and do a second bleeding, maybe a third bleeding on the third day.
 
  #4  
Old 01-13-19, 02:34 PM
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Hi, Spott!

Thanks for replying!

I do not see any purge valves above your pumps which would be used to bleed the air from your system. Correct. I don't see any and thus wondered if I could even purge the system.

There are different system designs and not all can be purged from the return line. You mentioned bleeding from air vents. Are those individual vents on the emitters (baseboards rads). Each radiator has a bleeder valve. I'm attaching pictures of them and the radiator.

What type of emitters do you have and how are they fed. You have 2 pumps so I'm assuming you have 2 zones with 2 thermostats. I can't tell you how they are fed. The basement is basically finished except for a few areas. In the few areas not finished, I can't tell if there is a tee or if the units are in a continuous loop. If there is a way to tell, please let me know.

In order to bleed your zones from the basement return line your piping needs to be a series loop system which means the water flows from one baseboard to another and another and back to the boiler using the emitters as part of the loop. We do have two pumps and thermostats. The air does go in a predictable pattern that one can hear but not in an order that I would think it should i.e. clockwise around the exterior walls of the house and then back to the pump. It seems to cut across the house. When one pump turns on, one can hear air somewhere and the column of air moves. It might start in one room one time, in another the next, or at the pump. The other system has some air as well but not as pronounced.

If your emitters are individually fed from the main supply with special fittings called monoflo or scoop tees they must be individually bled from the vent on the emitters and can be very time consuming and tricky. So lets assume that they are not in a loop and must be bleed individually. I have only been able to purge air from one radiator and it is not the most noisy one. I just can't figure out why air won't come out of the loudest radiator unless they aren't level and the air is collecting on the supply side. Would putting a bleeder above the supply help if this was the case?THIS JUST HAPPENED: I added a little pressure to the system to get it close to 15 psi. I went to the radiator that I have been able to get air out of and there has always been good pressure coming out of it if there wasn't any air in it. Now there isn't much pressure. Could something now be clogging this bleeder? Can bleeders go bad and only allow water to come out and not air?
 
  #5  
Old 01-13-19, 02:54 PM
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Hi, AllanJ!

Thanks for replying!

When you open the bleed valves on the radiators, does water come out? Water comes out on all of them. Air only comes out of one of the fairly reliably.

Gently lift the end of the baseboard radiator innards where the bleed valve is If there is any give then prop that end up using some small blocks of wood or other small solid objects. No give. These are heavy, cast iron units that seem to be secured to the wall. I checked the level from the top and they appear level. I don't know if the innards slope up a bit to force air where the bleeder is but that would make sense...

Gently depress the end of the baseboard innards without the bleed valve. If there is any give then weight it down. No give.

Try increasing the system pressure a few PSI by admitting a little more water into the system. If nothing at all comes out of the bleed valve then the system pressure is too low. I added a little pressure to the system to get it close to 15 psi. I went to the radiator that I have been able to get air out of and there has always been good pressure coming out of it if there wasn't any air in it. Now there isn't much pressure. Could something now be clogging this bleeder? Can bleeders go bad and only allow water to come out and not air?

Now try bleeding the radiators again. Just water...

It might be necessary to wait a day, add more water to the system. and do a second bleeding, maybe a third bleeding on the third day. Why must a system be off when purging air through? Since a column of air is moving through the system and I can get out air reliably through a bleeder and one knows that air is coming to that unit, it would make since to bleed as it is going through the unit or is there a risk of sucking in air or a burn?

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  #6  
Old 01-13-19, 03:00 PM
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Bleeding air is an art as well as a science. But, there has to be a way to do it on every hydronic system - it must have been done when the system was initially installed or opened for maintenance.

Try temporarily jacking up the system pressure to, say, 25 psi, and bleed each bleeder at the radiators - until water comes out - then stop and go to the next radiator. When the system pressure drops much below 25 psi, jack it back up. If this doesn't work, then the next step is a power purge using a garden hose - we can help you do that, but it might not be required.
 
  #7  
Old 01-13-19, 06:22 PM
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If you cannot see the piping or tees there is no way to tell. I'm guessing that because you have no purge stations on your returns and individual vents on the emitters you have a monoflo system which can be time consuming to bleed, especially with no shutoffs at each emitter.

First the system must be bled with the power off to the system, which means no pumps or burner running.

This part may take 2 people unless you are going to continuously run up and down to the boiler. You need high pressure as Gil pointed out.

Raise your pressure to as close to 30 PSI as possible without setting off the relief valve and start bleeding making sure that boiler pressure doesn't drop below 25 PSI. If it does, add water to get it back up. There is a reason for this but please just accept it for now.

Continue to bleed the baseboards one at a time until you feel all the air is out of each one. Don't be in a rush. Just because water immediately comes out of one, let it bleed for a minute or so, there may be air in the line.

Repeat this procedure until all are bled. When you're done you should still have at least 25 PSI in the boiler. Drain down a little water until you reach 20 PSI and that will be your cold operating pressure.

When you have finished bleeding and got your 20 PSI, turn on your boiler and test for proper operation. Hopefully the pressure will remain fairly stable which means your expansion tank is OK and your system is quiet which means the air is gone.

Why you keep the pressure high when you bleed is because when you are done you don't want the feed valve opening up to let more fresh water in bringing air with it. Every time you feed water into your boiler it brings air with it and that causes problems.

Any pics of your piping and expansion tank would be helpful.

Hope this helps a little.
 
  #8  
Old 01-13-19, 07:44 PM
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The board only gives a member 10 megs of picture storage. Your four pictures used up your entire storage quota. I cropped and resized your pictures. You're now under 1 meg.

Just wanted to explain why pics were edited. Feel free to post more.
 
  #9  
Old 01-14-19, 06:04 AM
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The problem with a finished basement is that when there is a problem above the finished ceiling you have no way to determine what type system you have. By the way, That cast iron baseboard heating system is the Cadillac of heating systems and was very expensive to install. Those baseboard rads are screwed to the walls so they will not move. Make sure that the screws are not extremely tight , The baseboard rads have to move to allow for expansion. Looking at the pictures you supplied, you probably do not have any zone valves but instead have 2 zones each having a pump and B&G flow control valve. Now, to your problem: trouble shooting your system is a crap shoot since no one is at your residence to witness the problems you are having. First, you said that you hear the air or something that moves around the system. Can you explain what you are hearing, it may not be air? Your system is probably not a series loop since it is cast iron baseboard, but it could be piped as a Monoflo, direct return or reverse return. Either way venting is the same. Go by what the guys have said about raising the pressure, turning off the system both pumps and the boiler and opening each vent in each piece of radiation 1 at a time. Check both ends of the radiation to see if vents are present on both ends. When you open a vent and the air stops you should get a steady stream of water. Let the water flow until you fill an 8 oz. glass. And "NO", you do not have a purge system. If this is a 2 story house start on the top floor and come down. You may have to vent the system numerous times, twice now and once or twice during this heating season. my 2 cents
 
  #10  
Old 01-14-19, 07:58 AM
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Hello, Everyone!

Thanks for responding to the problem we are having. We'll give it a go to see if we get somewhere with the air.

Steamboy asked me to explain what we are hearing. It is loud gurgling that could start at several different places but will move in a predictable pattern. In the radiator that the noise is most pronounced, it has a little clicking sound like a piece of plastic/metal loose in there.

I would assume that when we build up the pressure and try to bleed the individual units that we should time it so that the gurgling sounds are up in the house (ranch style) instead of the basement. Could the location of the air vent in the basement piping in the correct place to get air out of the system? One can see it in the 1st photo next to the pressure/temp gauge.

Our pressure tank is probably an old bladderless one. It is galvanized and about 12" by 48''. I wondered if that could be the reason we have so much air...

Thank you everyone for the feedback!
 
  #11  
Old 01-14-19, 08:25 AM
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What you describe is a conventional expansion tank, but I don't see it in your photo. They normally work fine, but you shouldn't have an air elimination device, which I see you have, because it will eventually deplete the air in the tank, causing it to become waterlogged - but it wouldn't cause the air in the system that you hear.

The piping from the system toward the expansion tank should slope upward so air in the system is returned to the tank. Please post some photos of your expansion tank and the piping connections to it.
 
  #12  
Old 01-14-19, 09:00 AM
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The copper pipe to the tank is level according to my level...
 
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Old 01-14-19, 09:13 AM
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The level section of pipe shown in your photo may be OK, but is certainly not ideal - it should slope upwards toward the tank. Likewise, I'm a bit skeptical of the horizontal elbow, the one to the right, in that same line - a vertical alignment would be better, like the el right below the tank.

Please post additional photos of the rest of the pipe and its connection to the system.
 

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  #14  
Old 01-14-19, 10:03 AM
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The vertical copper pipe off of the horizontal from the tank is the same thin vertical copper pipe in the first picture of this thread on the right. Let me know if you need other pictures.
 
  #15  
Old 01-14-19, 10:07 AM
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When water comes out of the bleed valve, close the valve.
Baseboard radiators with a single horizontal finned pipe may need to be bled multiple times over several days because only a small air pocket might collect at any given time and the rest of the air keep circulating.

You make sure that there is enough pressure in the system while bleeding so that air does not get sucked into the bleed valve when you open it. When air does bleed out you need to add more water to keep the pressure up with. Also, insufficient pressure together with a non-bladder expansion tank can result in air from the expansion tank coming down and circulating at large into the radiators and create a need for more bleeding.
 
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Old 01-14-19, 10:30 AM
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That part of the pipe shown in Post 6 seems OK to me.
 
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Old 01-14-19, 01:33 PM
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With that type of expansion tank you should not have any air vets in the basement. That conventional expansion tanks job, besides accepting expanded heated water is to accept unwanted air in the system which it cannot properly do if you are venting the air through open vents in the basement. That tank depends on air to operate properly, unlike the extrol tank which utilizes its own air bladder.

If your steel tank gets water logged over time the air, if you have any, has no place to go and just travels through the system until your tank gets drained and the air cushion restored.

With a metal object like a screwdriver tap the tank, top and bottom to see if it is completely full. You can tell by the sound change. In the meantime if your vent in the basement is automatic then close the cap tightly to stop the venting and let the tank do its job.
 
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Old 01-14-19, 03:41 PM
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Another way to check the tank air cushion and, if necessary, replenish the air cushion is to use the Airtrol tank fitting, in your photo a few inches to the left of where the pipe is connected to the bottom of the tank. If you want to try that, we can give you step-by-step instructions.

My ears are not the best, and I've had some trouble using the tap-tap-tap method for determining the water level in a conventional steel expansion tank. My success is improved by tapping on the end of the tank rather than on the side. Right now, my tank is half water and half air (with the system at 170 deg), which is probably about right for my system. My conventional steel tank goes indefinitely without losing any of its air cushion, and then only when I have to open the system for maintenance. A bladder-type tank will lose its air charge overtime due to diffusion of air through the bladder.
 
  #19  
Old 01-15-19, 04:43 AM
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For some of you younger guys, that fitting in the bottom of the expansion tank that "Gilmorrie " mentioned is not an air trol fitting but instead is a drain valve the likes I have not seen in many years. To make it work, you attach a hose, open the drain valve and wait for the tank to go into a vacuum, then you open the little fitting on the side of that valve to allow air to enter the tank to break the vacuum which then allows the tank to drain completely. Next item; a conventional expansion tank does not accept air from the system unless it is connected to an air separator like the Watts AS-M1-T (my opinion). To "Clange007, there are a lot of differing opinions as to the workings of all types of heating systems and I don't mean to insult or disparage any one for his answers or comments.
 
  #20  
Old 01-15-19, 03:08 PM
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We seem to be making some headway with the noise. We raised the pressure and drained every radiator but no appreciable amount of air came out of any unit. However, the gurgling is not noticeable yet so I'm wondering if the added pressure is doing the main work of cutting the noise down since no air came out... We are at 20 PSI when we used to be low to mid teens.

I'll keep working on it and will keep you guys posted. I just wanted to say thank you to everyone that contributed. It was hard to sleep.

Clange007
 
  #21  
Old 01-15-19, 04:03 PM
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C,
Thank you for the update.
 
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