Help: no water coming out when bleeding one zone


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Old 10-19-14, 01:21 PM
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Help: no water coming out when bleeding one zone

Hey,

As temperature drops, I am preparing my home heating system, which is a gas-boiler powered hot water with baseboard running in 5 heating zones. There are 2 zones on the 2nd floor; 2 zones on the 1st floor and one zone in the basement. All 5 zones share a water boiler, but has 5 separate outgoing and incoming pipes, with the circulator pumps attached to the returning end of the pipes.

Today when I drained the system, it went OK for all other 4 zones except one zone on the 2nd floor: after I attached the garden hose to the draining connector, and turned off the returning valve of that zone, there is no water coming out of the pipe!

I tried it with the circulator pump on and off, but it did not make any difference. Needless to say, the baseboard in this problematic zone never heats up.

Could it be that pipes in the trouble zone clogged up or is it the air? If it's clogged, any way to unclog it? If it's the air, how can it hold up the hot water pressure (the boiler is at the basement, if the hot water's pressure is not high enough, there is a chance that hot water won't be able to push to the 2nd floor).

I checked that there is no ventilation or bleeding valve attached to the baseboard/pipe of the problematic 2nd floor zone.

Any advice is appreciated.

P.S. There is a gauge at the front of the boiler with the upper portion (in red) indicating the temperature of water in the boiler (when the trouble zone is turned on, the temperature goes from 70F to 180F); the lower half (in blue) shows the water pressure -- it is suspiciously low: 7 or 8 PSI. Heating in the other 4 zones works fine.
 
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Old 10-19-14, 04:38 PM
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Please read this:

http://www.doityourself.com/forum/bo...ure-gauge.html

Presuming that your gauge IS accurate, 7-8 PSI may not be enough pressure to raise water to the second floor.

A blockage in the pipe is unlikely.
 
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Old 10-19-14, 04:48 PM
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Today when I drained the system,
Why did you drain the system? Usually, not a good idea unless required for maintenance - it injects dissolved air into the system.
 
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Old 10-19-14, 05:58 PM
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Good point Gil... I missed that when I read his post.

I would like to reinforce what Gil said, there is absolutely NO reason to drain and refill a hot water system as 'maintenance'. There is nothing to be gained by it, and indeed it does more harm than good.

The ONLY time a hot water system should be drained is for servicing something that can not be serviced without draining.
 
 

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