Hotown
Mechanical
- Jun 26, 2006
- 16
We have a drain that puts water into a sump at 3000 gpm for 1.5 min. The sump drains via a 20" line which travels for 2500' with 5 manholes installed. The first manhole is located 450' after the sump.
A change was recently made to the drain line 40' downstream of the sump where a section of the 20" line was cut and replaced with two 10" lines. Now when the equipment begins to drain water boils over the sump for ~30 seconds. The current theory is that the air cannot leave the pipe fast enough which is causing the drain to chug at the sump. It does not appear that we are pipe tight because 30 seconds into the flush the drain begins to handle the flow adequately.
What do you guys think? Is this a reasonable explanation, and if so does anyone have some insight on sizing a vent pipe for the drain line? Has anyone seen this before?
Thanks ahead of time for your insight.
A change was recently made to the drain line 40' downstream of the sump where a section of the 20" line was cut and replaced with two 10" lines. Now when the equipment begins to drain water boils over the sump for ~30 seconds. The current theory is that the air cannot leave the pipe fast enough which is causing the drain to chug at the sump. It does not appear that we are pipe tight because 30 seconds into the flush the drain begins to handle the flow adequately.
What do you guys think? Is this a reasonable explanation, and if so does anyone have some insight on sizing a vent pipe for the drain line? Has anyone seen this before?
Thanks ahead of time for your insight.