Air Eliminator piping configuration question

elfie

have this old arco 915 air eliminator  mounted along a dry return and am wondering why there is a second vertical pipe added, which is joined to first vertical pipe close to the water line.



i saw a pic of another arco 915 and the piping configuration was the same, so it must be a design feature relating to this air eliminator.



thanks

moneypitfeeder

maybe

looks like a balance pipe, or equalizing pipe most of the various air eliminators had them.

nicholas bonham-carter

Air eliminator

I see what appears to be a check valve on the line, so I wonder how the vacuum wil be relieved at the end of the firing of the burner. Most systems which are no longer being fired by coal have had the vacuum features removed/disabled.--nbc

elfie

balancing pipe

how did balancing or equalizer pipe work?



thanks,  it has been a longstanding question



i understand that the air eliminator vented air and that the check valve prevented the return of air back into the system (ie. to preserve vacuum)  - but the functionality of the second pipe is still unclear



the returns are connected to a condensate pump (which is vented) and therefore since coal is not longer used it may make sense to eliminate this antique (which leaks steam)

gerry gill

The pipe in question

is the main return pipe drip which is sized as the same as the horizontal return main..The tee pointing down to the air eliminator should have been installed facing up so that air passed thru it and not condensate.. The check valve does not need to be there as the air eliminator should have been a float type..however it won't hurt anything..the drain coming down from the float air eliminator was how water would get under the float and lift it to close off the air vent should the boiler pressure get to high and cause water to back up the 'b' dimension..(except you have a check valve there)..

elfie

air eliminator

thanks for a great reply



 i had always thought that the air eliminator reservoir accumulated condensate and the float released water down the pipe when water level rose



however, this appears wrong.



it should be only going into this device (not sure i understand how the float mechanism worked.



the connection to the air eliminator incorrectly allows condensate to flow into it - if connection to air eliminator was done as you suggested this would mean the condensate would and should have flowed down the other pipe, with only airallowed to enter the air eliminator device (thermostatic trap would have prevented the steam from entering the air eliminator)



please clarify how the float mechanism worked



thanks so much







 

gerry gill

usually there was a device

like a ball that floated, or something shaped like a beer can or an upside down cup that floated up to block off the air vent opening when water rose up the pipe..modern main vents many times still have a float mechanism in them also.

elfie

water flow dynamics in pipe going down from air eliminator?

hi, thanks



with the piping going up (rather than down) to the air eliminator it makes sense in light of the second pipe going downward that would then be receiving the condensate flow.



and because of this, it would seem that not much condensate would ever enter the air eliminator and the reservoir would not be very active.



you mention water filling up the pipe underneath the reservoir (does this mean the check valve direction has flow of water going up to the air eliminator? which would cause the ball to plug off the air vent and by not relieving air from system cause the boiler pressure to go lower??



i guess i dont completely understand how water flows thru the pipe beneath the air eliminator and its impact on pressure. the existence of the check valve with a direction of flow going lower doesnt make sense and the water boiler water level is alot lower than the air eliminator so water backup up to the air eliminator is tough to understand



i think i am close



thanks so much

gerry gill

when boiler pressure

is exerted down on the water at the boiler, the water draining back from the return has to stack up until its vertical column is high enough to weigh enough to over come the boiler pressure and slide back into the boiler..if the boiler pressure were to go to high, then the water may stack up high enough to squirt out the air vent..so a float usually will rise to stop that from squirting by closing off the air vent..attached is a drawing of an arco system that used an ac/heat coil in it..the air eliminator is in the drawing tho..maybe it will help alittle.. is there any info on that tag that looks to be painted over? whats it say? i've been trying to find the patent for you but have only succeeded in finding the orifice radiator valve..any info from the tag may help.

elfie

label info from air eliminator

your info is wonderful







here is a close up pic of the air eliminator







it says



No #915 Arco



Multi-Port



Air Eliminator



there is also an end of main Arco 911 trap (have learned this is very rare)

dont see any end of line trap on the system drawing info you provided



i guess air eliminator has two purposes - eliminate air initially which is then stopped when thermostatic trap closes and then when boiler pressure rises, the float seals the vent to prevent water from spouting out the top of the device.



seems very odd a check valve has been installed which would prevent the water level from going back down (very odd) and therefore reservoir of air eliminator would seem to have trouble venting air since the reservoir would be backed up with water  - i need to recheck check valve to see if there is an arrow - maybe some one put it on later and its going down



very helpful

thanks