Air in second floor loop

doublekay

Hello plumbing/heating gods. Forced to turn on the heat the other day and had a crap ton of air on the 2nd floor zone. Spent 4hrs yesterday bleeding the loops and still a ton of air. Shouldn’t be that hard I must be missing something.

Here is what I did, and a picture of set up..

• hose to Spicket on return, just above circulator pump
  -shut return valve to boiler just below said pump
  -opened zone valve to second floor (left the rest closed)
  -opened spicket, flipped up auto fill, ran forever, water flow perfect. Flipped auto fill to auto.
  -shut off spicket
  -put zone valve back to auto.
• repeated every zone like that.
• result… a bit better but still a lot of air. Can hear it passing though the circular pump.

Only bleeder/self bleeder in the entire system is above the expansion tank.

The First try I did the day before, I shut off the return sides of every zone

I wasn’t flushing but still had air. So did it all a second time and only used zone valves. Seemed to work till boiler relief valve popped when boiler got hot.

I’m doing something wrong, this shouldn’t be that hard 🙄🙄🙄. Any suggestions??

Thanks in advance. KK

jesmed1

This is a question for @EdTheHeaterMan . I'm guessing he's going to tell you that your pressure is too low when purging.

AndythePlumber

from the pics your valve operations seem perfectly fine. If there is a lot of ups and downs it can be difficult to get the air out of those pockets up in the second floor. Go through your baseboard up there and look for bleeders. I will check back to see how you’re doing

AndythePlumber

and yes make sure your makeup water valve is operating properly to maintain pressure whilst purging. It would be great to have a bypass for that but definitely not necessary. Also, besides the temp/pressure gauge on the boiler it would be great to have a way to verify pressure. I have a reliable gauge I can screw onto the boiler drain hose threads to field verify pressure. The one on your boiler may or may not be accurate.

hot_rod

did you put the fill valve in fast fill mode, by lifting the lever?

Also the backflow probably has a screen on the inlet, they plug easily and will limit your fill valve flow

doublekay

Thanks for all the feed back. What a great group.

Unfortunately there is no bleeder anywhere on the 2nd floor baseboard.

Yes I had fill valve on fast fill, but I did put it back to auto before I closed the drain valve, so maybe that may have been an issue???

I will definitely have to check that screen on the makeup valve but I seemed to have pretty good pressure. I will try a gauge on the drain hose as well

I guess I’ll give the entire system another try this weekend and leave the fast fill on the entire time untill I flip the zone valve back to auto?

Thanks again all. I’ll report back

EdTheHeaterMan

@jesmed1 may have the answer. If you are trying to push air down a vertical pipe you need some velocity. If the water flowing down the pipe is not flowing fast enough, then it will be like a water fall, just pouring over the edge of the top elbow, and allowing the air to float back up to the top. If however you force the water down the vertical pipe with some velocity then the air will be pushed along with the water and be forced out the open purge valve.

There is an ideal way to pipe a system to purge air and get the greatest amount of velocity without worrying about the relief valve popping open. I will explain it to you the way I learned about from The Great Dan Holohan God of Hydronics. (only using @doublekay term from above)

I used to teach this in my one day Hydronics seminar for EH-CC.org

Off Topic: Who is Alpha❤️? and why isn't it hanging up in a Mancave somewhere?

neilc

xmas decorations

jesmed1

@EdTheHeaterMan Don't you get yourself kicked off the site too. We need you!

doublekay

lol. Good eyes @EdTheHeaterMan… long story.

okay so that does make sense to me as the last elbow on the 2nd floor drops straight down to the basement before it 90s for 3 feet to the return manifold. I’m confident I’m adding just about as much pressure as possible (house on a 60/40 water pressure)

So my next question becomes what todo now? I’m guessing that there maybe a couple of solutions, but what is the best solution?

-Try again, leave on fast fill the entire time to include as I flip zone valve to auto, which will hammer the zone and starts to add pressure to the boiler and quickly shut the drain?

- Install a bleeder on the 2nd floor and if so where? Beginning, Middle or end of the second floor loop? And then do above?

-Something else?

Again I feel compelled to say what a great group this is. Hopefully someday I can add to it rather than take from it. Appreciate the help

EdTheHeaterMan

OK I have had your situation many times. You may need to build up pressure in the expansion tank by closing the valve to the garden hose valve, until you get to about 26 PSI on the gauge then open the valve and let the water push as much air out as it can until the water pressure drops to 10 or 12 or what ever. then build up the pressure again by closing off the garden hose until the boiler gets to 26 PSI. then open the garden hose again and let that force push more air out. You may need to do this 5 or more times or until you done get any air. Each time you will get a little more air to purge. Once you no longer get air, that that top floor loop is air free.