Air Vent at boiler. Necessary with Air Sep?
Hi everyone,
I noticed my boiler (CG8 hydronic) has been operating for years with the boiler vent pipe capped (no auto-air vent). If I install a Air Separator at the supply of the boiler above the expansion tank (I will be pumping away), should I also add an auto air-vent on the boiler? Thanks for your advice!
Comments
-
Unless there is a high point trap that would require venting, no
1 -
That will depend on the type of compression tank you're using. (expansion tank). If you have a tank that has some type of membrane that separates the air from the water side of the system, then of course you should have an automatic air vent somewhere.
If however you have the older technology steel compression tank where the air and the water are in contact with each other, then you may want to make sure that the tank is equipped with the AirTrol® tank fitting, and use the top of the air scoop to vent air into the compression tank.
Can you explain the reason you feel you need the air separator? Are you experiencing air problems?
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
Thank you @EdTheHeaterMan . I have a EX60 membrane-type tank. Reasoning for adding an air-seperator is to help prolong the life of this old, cast iron boiler. Ive always had issues with bleeding the fin-tubbed heat emitters on the top floor. Hoping this conversion to pumping away will help, as well as air sep and/or automatic air vent at the boiler. Am I off track?
0 -
Depends on the circulator location. If you have the air sep on the supply (HOT) side of the boiler piping and the circ is pumping away from the air sep, AND you attach the Ex-60 expansion tank and boiler fill valve at that same point, you will actually eliminate the air problem. It all has something to do with the Physics of Water and Boyle's Law of dissolved gasses. Long story short… Hot water and low pressure will release dissolved air. Put a vent there and all the air in the system will get absorbed in the water and released at the air sep. (ask me how I know this)
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0 -
what is the static cold fill pressure and how high above the boiler are the problem emitters? you might need a little higher cold fill pressure to keep adequate pressure at the top.
0 -
Thank you @EdTheHeaterMan and @mattmia2 . Yes, on the supply side: boiler - expansion/airsep-circ.
circ to top radiator is roughly 17feet.202,000 output boiler.
Once a gravity system.
1 -
currently 15psi
1 -
thats a lot of heat.
how big and where is this home?1 -
Thanks @pecmsg. 1937 4-family apartment building. (2bed 1 bath). About 4000 sq/ft.
Brick. Cincinnati, OH.
0 -
17 feet above the circulator pump that may be about 3 feet above the boiler pressure gauge indicates that you need about 8.9 PSI of static pressure to get the system filled. add a little extra for a buffer and you can operate at 12 PSI for that system. So 15 PSI at the boiler gauge is more than adequate without going overboard. Set the air charge in the expansion tank to 15 PSI when the expansion tank os not connected to the boiler water pressure. That would mean with the boiler pressure below 12 PSI if you want to check it without disconnecting it. Then set your auto fill pressure to 14.5 PSI to 15 PSI so not to add more water to the 15 PSI expansion tank at cold startup. You should be good to go with pumping away from the expansion tank!
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
19374-family apartment building. (2bed 1 bath).
that is a lot of families for only 4000 sq ft. L🤣L
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0 -
-
I still think you have a lot of families in the 4000 sq ft building
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0 -
Ha! Well its just 4 (actually just 8 people).
How does this look?
0 -
Just curious,
but have you tried simply turning up the high limit temperature of the boiler for a few hours to force the air bubbles to a new larger automatic air vent? that is the easy way to remove trapped air slugs.
You can simply install the new air vent with a reducing bell, pipe nipple, ball valve, pipe nipple and coupler the size of the automatic air vent.
The use of a ball valve lets you change the air vent by simply shutting the valve off when it starts leaking.
The one inch male thread air vent in the attachment is just one model size offered by Mcmaster-Carr.
1 -
Thank you, @leonz! I have not tried this. Excellent idea. Are you suggesting the boiler vent port (which is currently capped?)
0
Categories
- All Categories
- 87.1K THE MAIN WALL
- 3.2K A-C, Heat Pumps & Refrigeration
- 58 Biomass
- 427 Carbon Monoxide Awareness
- 114 Chimneys & Flues
- 2.1K Domestic Hot Water
- 5.7K Gas Heating
- 111 Geothermal
- 163 Indoor-Air Quality
- 3.6K Oil Heating
- 72 Pipe Deterioration
- 1K Plumbing
- 6.4K Radiant Heating
- 393 Solar
- 15.4K Strictly Steam
- 3.4K Thermostats and Controls
- 55 Water Quality
- 46 Industry Classes
- 49 Job Opportunities
- 18 Recall Announcements