Boiler bypass piping...

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  #1  
Old 07-20-12, 05:10 PM
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Boiler bypass piping...

Hopefully, I will be doing this soon. Any help is appreciated.

When boiler piping as in the link below, but with zone valves (or always open), where would the pump go?

http://comfort-calc.net/pictures/Boiler%20Bypass.JPG
 
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Old 07-20-12, 06:07 PM
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Can't view that.

For a boiler bypass, the bypass goes between the boiler and pump.
 
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Old 07-21-12, 08:51 AM
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Can't view it because there is a space in the file name. Hopefully the owner of the site comfort-calc.net can fix it so it can be put to good use.
 
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Old 07-21-12, 12:50 PM
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Heres the image of the boiler bypass, this image has 3 circulator pumps, I am looking to use only one pump. If anyone has a more detailed image, please post.

image courtesy comfort-calc.net
 
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Last edited by NJT; 07-21-12 at 06:20 PM.
  #5  
Old 07-21-12, 01:48 PM
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Put the pump right after the expansion tank. Use closely spaced tees for your zones and place zone valves where the drawing has pumps.
 
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Old 07-21-12, 04:49 PM
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Use closely spaced tees for your zones
Please elaborate...

We usually use the term 'closely spaced tees' when referring to the primary/secondary setup.

In this case, it's just a manifold, and the tees don't really need to be 'closely spaced', you want to leave enough room for service/maintenance between them.

But yeah, just replace those pumps with zone valves, and your single pump goes between the air separator and the manifold with the valves on it.

Be sure to read the specs on the air sep that you plan to use, some require 18" of straight pipe before and after.

That graphic shows check valves after each pump, with zone valves you won't need those.
 
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Old 07-21-12, 05:01 PM
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Please elaborate...
I thought the tees needed to be close so the flow in the zones would be equal when they were all open. Shrug! I'm just an amateur.
 
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Old 07-21-12, 06:21 PM
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No, not really... what's more important for that to occur is that the main manifold be large enough so that it can easily feed all the open zones without one zone 'robbing' another.
 
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Old 07-21-12, 07:12 PM
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Wouldn't the single pump be better placed on the return side right before the bypass pipe tee?
 
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Old 07-22-12, 08:19 AM
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No. You want it on the supply after the expansion tank as per the specs of your air separator.
 
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Old 07-22-12, 09:39 AM
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The point is to 'pump away' from the Point Of No Pressure Change (PONPC) which happens to be the connection point of the expansion tank. This causes the pumps 'head pressure' to ADD to the dynamic system pressure rather than subtract from. This results in much better control of the air in the system.

I'm sure we've discussed this before! no?
 
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Old 07-22-12, 10:00 AM
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This quote below is from is from Bypass_Piping_Explaination

Although I show a diagram with the circulator mounted on the return the standard today is to have the circulator mounted on the return pumping away from the expansion tank.
Can someone clarify this?

Thank you
 
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Old 07-22-12, 11:19 AM
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Clearly a typo. Although the info on the site is really good, it is full of typos. He means to say the standard is to have the pump on the supply.
 
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