Air In Hot Water Baseboard System

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Old 10-28-08, 06:32 AM
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Air In Hot Water Baseboard System

Hi guys, I've been reading thorugh the forums ever since I bought a home in August and it's a very helpful site. I am new to EVERYTHING about a home since this is my first home and I never did any work on anything around a house before. I am very mechanically inclined though. Here is the issue: I have a gas fired boiler (It's a Burnham Series 2 Boiler, pretty sure it is the original one from 50 years ago). I don't know all of the terminology for heating/plumbing but I will try to explain my system starting from the cold water feed. The cold water feed goes through an auto-feed/pressure regulator which ties into the RETURN pipe. The circulator is installed at the return right before it goes into the boiler. On the back of the boiler there is a pipe going up with a relief valve and then it goes up to a steel tank (expansion tank? holding tank?). The supply comes out of the boiler and then it splits. The first split goes up to the second floor and loops around the perimeter and comes back down to what I will call RETURN #1. The second split goes out and SPLITS AGAIN. One split heats half the kitchen, the bathroom, one bedroom and then goes into what I will call RETURN #2 (both returns join up and become one). The other split heats up the other half of the kitchen, the living room, then it comes down and heats the basement, then it comes back up to to heat the other bedroom and then returns at RETURN #1 (the upstairs return is connected with a T at RETURN #1). I am not a plumber/HVAC tech, system designer, or anything along those lines, but this system is laid out very weird to say the least. Sorry for the long explanation, my problem is that I have air in the system and it's driving me nuts. There is an air bleeder valve at every baseboard in the house at at many other high points in the system (GOOD THING). I let all of the air out at each valve last night while the system was hot and running and the noise in the pipes went away. This morning, the noise returned. I don't know what else to do. Here are my questions if anyone can help me:

Am I doing something worong? If so, what?

Is there any other way I can bleed the air out? (The system was purged already)

Will an ir scoop and a bladder type expansion tank solve my problems? If so, where do I install it? At the supply which is after the pump and after the boiler, or at the return before the pump and before the boiler?

Any comments/advice would be appreciated.
 
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Old 10-28-08, 03:47 PM
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What pressure is the system running at?
Doug
 
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Old 10-28-08, 07:32 PM
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Doug got my question! first thing I was gonna ask..

what is the pressure both COLD and HOT boiler ?

while yer lookin' at the gauge, might as well tell us what temperature yer taking the pressures at too ...
 
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Old 10-29-08, 04:54 AM
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I won't be home again until Thursday afternoon so I will get the pressures and the temps later. I do remember when it was between 170-180 (it is set at 190 and the boiler stops running at exactly 180) having a pressure of 18 psi.
 
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Old 10-29-08, 02:50 PM
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We'll wait for your report. But, in the meantime, here is some preferred nomeclature that will make things a little clearer in future posts:

Saying the boiler is "running" might mean different things. If the burner is on, then the "boiler is firing." If the pump is running, then the "the circulator is running."
Doug
 
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Old 11-01-08, 06:14 AM
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It reads 18 psi @ 180 degrees, and 15-16 @ 70-80 degrees. I worked my way around the air bleeders at each baseboard four times. I did it once when the system was cold, working from downstairs up. Then i did it one more time when it was hot, working from downstairs up. I repeated the process the following day but worked from upstairs down. The baseboards are very quiet now. I do not hear any air in the system. I went to a couple of baseboards and used the bleeder valve but only water came out and I did not hear any air before the water came out.

I am happy that I have no air but now that I have done so much research about my heating system, I will like to upgrade the system without replacing the boiler. My budget right now only allows me to add cerain things to it. I will like to remove the old compression tank that is in the basement ceiling and install an air separator, diaphragm type expansion tank, and an anti-back flow valve. I will be installing the expansion tank and air separator on the supply side AFTER the pump and piping the water feed below the air separator, above the expansion tank with a tee. Is this correct? Will this prevent any other air issues with my system in the future?
 
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Old 11-01-08, 08:35 AM
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Pressures are great...no trouble there.

installing the expansion tank and air separator on the supply side AFTER the pump
If by 'AFTER', you mean 'DOWNSTREAM', then no, that's not correct.

The tank should be installed BEFORE, or UPSTREAM of the pump so that the pumping flow is AWAY from the tank.

The tank should be on the SUCTION side of the pump.
 
 

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