Can't stop gurgling in hot water baseboard heat

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  #1  
Old 11-27-04, 07:06 AM
tomd514
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Can't stop gurgling in hot water baseboard heat

Everytime a zone calls for heat in my four zone hydronic heat system, I hear the initial gurgling of water rushing in the baseboard units. I have installed manual bleeder valves in the baseboard units but no matter how many times I bleed each unit, I still hear the gurgling. Everyday I release the schrader valve on top of the boiler mounted air scoop, I get a 2-second release of air before it hits me with a shot of hot water.

I've read that there's a certain amount of air in the city water supplied to the boiler which could be the reason for bubbles. However, I don't believe I'm adding that much water (other than from the occassional bleeding exercise) to cause the gurgling sounds.

Is there a way to purge the whole system of air?

Here's a schematic of my system:

Boiler outlet
|
Air Scoop (with air vent (schrader valve) and expansion tank)
|
Four zone valves
|
Four loops return to common 1" pipe
|
Ball valve with boiler drain stop
|
circulator pump
|
boiler drain valve
|
return to boiler

thanks,
 
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  #2  
Old 11-27-04, 11:13 AM
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Is this a new heating system, or was it recently drained for some reason?

It can take a while to bleed all of the air out of the system. As long as you are getting air out of the bleed valves, you will probably hear gurgling. Are you bleeding the system with the circulator off?

What is the pressure at the boiler, and how many floors are you heating?
 
  #3  
Old 11-28-04, 07:35 AM
tomd514
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The last time I opened the system was over a year ago (removed a rusted baseboard unit for a bathroom).

Pressure at the boiler is 15lbs.

The boiler is in the basement, loop one feeds the first floor starting directly over the boiler-five baseboards, loop two goes to the second floor-three bedrooms and a bath, loop three is also on the first floor-two infrequently used rooms and loop four is in the basement- two baseboards adjacent to the boiler room.

The method I've been using to bleed each loop is to crank the thermostat on and bleed each baseboard until steady stream of hot water (no spits).

I thought I heard of a procedure where the domestic water pressure is introduced to force out the air? Is this something I could try with my system?
 
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Old 11-28-04, 08:18 AM
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You are probably using domestic water as boiler make-up water now. If you trace the water supply piping to the boiler, you should see an auto-fill valve, it kind of looks like a bell with a stem or knob out the top if it. You might try increasing the boiler pressure to 18 psi by tightening the stem on the top of the auto-fill valve (you should hear water flowing thru the valve).You do not need the circulator running to bleed the rads.

I am assuming you put the radiator bleed valves at the highest point on each radiator. Air will accumulate at the highest point in the system, and you need a way to bleed it from this point.
 
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Old 12-03-04, 05:14 AM
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same problem

Guys,

I have the same exact problem...4 zone baseboard heat with a new crown boiler....Have bleed 1 zone twice and changed the auto bleeder....still here some water gurgling every so often.....

I was reading where it said to try to lift up the ends of the elemnet to change the pitch of the pipe and force air out? Could that work?

Is it possible I have a leak?...Some of the piping is behind walls, thru ceilings, and not visible to the eye...

Anything you guys figure out will help!

If this problem stays the same and I here a little water once in a while sloshing thru the pipes, will this cause damage to my boiler? That is my main concern...
 
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Old 12-03-04, 07:59 AM
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Wink

jritkes
Yes for sure you want to get the air out of the pipes and baseboard . Can it be that the Psi on the boileris not up to what it should be????

ED
 
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Old 12-03-04, 08:04 AM
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The boiler pressure reads between 18 and 20 constantly...From what I'm told this is correct...Any other ideas??

Thanks for the answer....
 
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Old 12-03-04, 08:11 AM
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One other thing...I started to hear this gurggling and then my 10 year old slant/fin boiler went and I had a new Crown boiler installed, and still hear the water...Is it possibly something with the pipes??

Pitch?

Crack in the piping?

Blockage??
 
  #9  
Old 12-03-04, 05:22 PM
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Poor air elimination at the boiler is as aggravating as noisy pipes. It can be easy as pie but nobody bothers to read the directions that come with the air scoop or get a better air eliminator. First of all, TURN THE THERMOSTAT ALL THE WAY DOWN. you do not want air or water to be moving around the system while you are trying to get rid of that air. Stop the system and the air will go to the highest point. That is where the bleeders are and you can get the air out. It never hurts to lift the element up with one hand while turning the bleeder with the other. That way you know that the bleeder is at the highest point on the baseboard. My guess is that this will take care of 99% of all bleeding problems. You may have to do it twice or even 3 times, but you will get it all eventually. Increasing pressure won't help eliminate air, but it will get you closer to the 30psi that opens the relief valve. Lower is better.

By the way, the directions on an air scoop say it must be installed with something like 20" of straight pipe before it. Most have an elbow screwed into the inlet end or are connected to the flow valve or for some other reason are made useless.

Ken
 
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Old 12-06-04, 04:32 AM
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Ken,

Questions.

1- Turn the thermostat all the way down.-You mean turn all 4 zones I have down(off) so the water in the base board has cooled considerably in all zones?

2-I have Honeywell auotbleeders-When they were installed the person left the cap on it as loose as possible. I guess to let out air when it needed to. Should he after bleeding the zone have tightened it right off the bat (could this let air in).?

3-If this was correct, then when you say let the air get to it's highest point should I tighten the cap on the bleeder before I shut down the thermostat? Because once I do what you are saying and if I leave the cap very loose like it is, I have no way of manually causing the bleeder to work. It does not have a pin. Supposed to work on it's own.(so if I tighten first, let cool, then open, maybe it will let air out?)but should'nt it let air out automatically as it passes by the bleeder when in use?
What should I do?

4-Last question-How does air keep getting back into my system after being beld and will this damage my boiler? Thanks for all you help!!

Sorry about all the questions. Just want this resolved.

Jeff
 
  #11  
Old 12-06-04, 07:28 PM
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If you have automatic air vents, they should work on their own. However, when an air vent is at the top of a system, it can also admit air to the system. I would suggest closing them when the system is not running and in between heating cycles open them and see if air comes out. Leave them closed after getting all the air out because you don't want to risk water damage if one leaks or letting air in if that is what is happening.

Ken
 
  #12  
Old 12-16-04, 05:32 AM
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Help,

I am still hearing the water in the baseboards, but I only bled two zones because that is where i heard the water....Now i hear it upstairs in my bedroom zone...Is it possible that because I only bled two zones that air is in the other 2 zones? Should I have bled all 4 zones?

Thanks
 
  #13  
Old 12-16-04, 09:28 PM
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Air will migrate to the highest point in the system. Close the bleeders on the lower zones, and go bleed the upper zones, with the circulator not running, i.e. turn down the t-stat for those zones.

Once you get all of the air out, close them, as Ken said earlier.
 
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