Bleed air from HVAC

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  #1  
Old 06-06-15, 09:54 AM
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Bleed air from HVAC

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My condo heat and AC runs on a central boiler and chiller for the whole complex. Every spring and fall when they switch from heat to cool I have to have the air bled from the units in my ceiling or it just blows room temperature air. I'm tired of paying to have this done! The unit seems to only have 3 components; it looks simple but I can't figure it out. A) the water valves B) a small hex nut valve of some kind and C) the electronics. B) seems the most likely candidate, but loosening the nut all the way didn't do anything. Any ideas? Thanks!Name:  IMG_20150606_093852.jpg
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Old 06-06-15, 10:00 AM
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B would be your bleed off valve.
 
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Old 06-06-15, 10:07 AM
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Like skaggsje mentioned B is the bleed off valve. Since it's connected to a drain line you aren't going to hear anything. Open that valve a few turns and wait until the temperature of the pipes gets cold and then close it.
 
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Old 06-06-15, 10:12 AM
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In your A picture looks like both your valves are closed. Make sure you open those before bleeding.
 
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Old 06-06-15, 10:12 AM
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I'll give it a go, thanks! Yeah I closed the water lines before trying because I was afraid water would spray out. I'll reopen those first.
 
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Old 06-06-15, 10:27 AM
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I would leave the ball valve that your saddle valve is mounted to off.
I would get a small bucket or attach a drainline on the saddle valve and open it a few turns.

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I would slowly open the ball valve that is on the pipe that doesn't have the saddle valve to force the air out of the coil.

I would then close the first ball valve and open the second to force the remaining air out.



HVAC companies must be licensed and insured to work in condos.
I work in buildings that have up to 260 psi on the lower floors.
 
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Old 06-06-15, 10:59 AM
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Thanks Houston for highlighting that the bleeder valve was not connected to a drain line.
 
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Old 06-06-15, 11:03 AM
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I tried Houston's method and nothing comes out of the bleed valve. The pipes are cold so there's definitely water in them.
 
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Old 06-06-15, 11:15 AM
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Should the lower copper pipe here be cold? Looks to be the return line. Name:  IMG_20150606_093852.jpg
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Old 06-06-15, 11:34 AM
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If both of the pipes are cold then you don't need to bleed it.

That saddle valve is probably plugged. That was a poor choice of valves to put there. I'm guessing an HVAC tech installed it as it's definitely aftermarket from the original installation.
 
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Old 06-06-15, 12:15 PM
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I removed the saddle valve and cleaned it. Pretty rusty. The air is running cold now so with all the messing I guess it worked. I just expected more to happen when I opened the bleed valve. Thanks!
 
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Old 06-06-15, 06:43 PM
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It takes a hole for water to come out. It only takes a tiny pinhole for air to purge out.
 
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