hot water coil in attic.


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Old 10-20-12, 06:12 AM
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hot water coil in attic.

Maybe you can help. I ran 1" pex 4- feed and 4-return from boiler to coils in attic. There's 4 units. We keep having problems with air and we keep purging. Works for a week or two and stops. The boiler is about 35 ft below units. There's air vents on coils both sides and we raised pressure on boiler to 19lbs. I think the coils should be installed with in/out on the sides to get air to the tip. my hvac guy has them with in/out on top. I can picture air getting caught on all the little turns of coil please help.
 
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Old 10-20-12, 06:40 AM
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install automatic air vents?..... A picture would really help.
 
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Old 10-20-12, 07:00 AM
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there are air vents on both sides feed and return
 
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Old 10-20-12, 07:29 AM
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you said you had to purge indicating the air vents are not automatic or they are not working properly or they are not located in the proper location. Again, a picture would help.
 
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Old 10-20-12, 11:42 AM
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In my opinion the water supply to the coil should be on the side and the lower connection. Do not include an air vent on the supply but only the return connection. Include a tee and short nipple on the return to allow for an air collection space. Install the float automatic air release here.

Try also increasing the static pressure to 20 psi minimum. If this causes a hot pressure in excess of 27 psi then you need additional (or larger) expansion tank capacity.
 
 

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