Boiler Purge Design

Old 02-27-17, 07:56 AM
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Boiler Purge Design

I am trying to piece together a boiler system for my shop. I have a bunch of parts from a previously working system and trying to include these to save money.

Any thoughts or suggestions on this by looking at the pictures? I wondered why some purge valves have a cut off built in? Would I need to add a cut off after the purge valves?

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Last edited by Steven Johnston; 02-27-17 at 09:20 AM. Reason: change design
Old 02-27-17, 09:25 AM
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Zone valves will work on either supply or return lines.

A couple things you must consider.
Zone valves are directional and must be installed properly. They will only work with going in the direction of the arrow installed on the valve body. Next, the second is use common sense in piping the system and put valves and purge station where needed.

The bottom pic with the ZV's on the supply will work for purging, making sure the ZV's are going the right way, by using the ZV as a shutoff when purging.

When purging each zone you would shut off the other 2 zones and open the ZV manually, allowing water to flow through on the zone you are purging as long as you have the ball valves coming off the main as pictured.

One more recommendation I would make is to get rid of those air vents on the 3 zones and plug the openings. A properly purged zone will stay air free unless opened or if there is a problem which those vents can create. If they fail they will not only leak but can also suck air into the system needlessly giving you problems.

If the system is properly bled the vents have no purpose anyway because there is no air to bleed.

Bleeding is all done with the system off of course.

Hope this helps a little.
Old 02-27-17, 03:23 PM
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I would leave the vents on the 3 zones for any air that is released when the water is heated for the first time. Cold water has a tendency to hold excess air until heated.

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