Air elimination question

Snowmelt

I have a school with a boiler doing an auditorium and about 8 classrooms, plus the hallway. It’s a few 100 feet of piping, now air elimination except the lob style air scoop, all pipes are visible, has a lot of air in the system. Also the pipes are going up and around a few doors then back down with little air vents on top, really not doing much in general. Also almost like a mono flo system where it goes from auditorium to classrooms.
Should I install just a 2 inch 4900 at the boiler supply or should / could I install a few 1 inch Seperator where the air is staying, i here the water running or should I say I hear the air in the pipes all over the place.

hot_rod

A Caleffi DiscalDirtMag at the boiler would give you 3 critical functions

High points could benefit from some auto float style

Pumping away from the expansion tank?

GroundUp

Define "lob style air scoop". There is absolutely no reason for multiple air eliminators if the system is piped and pumped properly

Snowmelt

Oops , old style air scoop. ,

Thanks hot rod, let me ask in an older boiler, or any cast iron boiler , with a ordinary pump, do you recommend a boiler cleaner like Sentinel X300
System Cleaner for New Hydronic Heating Systems?

HVACNUT

Diagram or compression expansion tank(s)?

Snowmelt

Diaphragm

hot_rod

> @Snowmelt said:
> Oops , old style air scoop. ,
>
> Thanks hot rod, let me ask in an older boiler, or any cast iron boiler , with a ordinary pump, do you recommend a boiler cleaner like Sentinel X300
> System Cleaner for New Hydronic Heating Systems?

Drain some water, see what it looks or smell like. Some older iron steel systems are amazingly clean, others that drain black “boiler ink” could use a good cleaning. Black water often indicates magnetite from corroded ferrous metals. Which also indicates ongoing O2 ingress

If the system has a chronic air problem it could be sucking air in
Which can often be traced to improper expansion tank connection and high point auto air vents allowing air in.

Adding a air dirt sep with a magnetic function will protect the system best, especially if you detect magnetite

Take a magnet to any boiler water that drains black or red.

Snowmelt

it does have high vent cans that i don't think is doing nothing , i will tell you this the higher vents are 12 and 20 feet in the air. I'm thinking that might be the problem. water in somewhat black and sometimes brown........ when i say brown i mean where the air vents are and they must of been leaking at one time the pipe has brown scum on it.

hot_rod

You want a positive 5 psi at the highest vent to assure the best seal. Certainly no harm in running a cleaner

Snowmelt

thanks HR, I am not a job sight but in my head i think the pump is on the return but 6 feet away from boiler and the expansion tank at the boiler using one of the tapping coming out of the top then brought tothe side of the boiler , like a 13 or 20 gallon tank

Solid_Fuel_Man

On large commercial (read big circulators) pumping away is absolutely critical. Move something, either the pump ideally, or at least the connection to the expansion tank to the suction side of the pump. This is absolutely the first step in chronic air systems. All those auto-vent cans are likely going into a vacuum and pulling air into the system.

This is a medium size commercial job I was at with chronic air problems. Had two circulators running at the same time (bad control system) this is with just one circ running. Pumps on return into the boiler etc.

Snowmelt

thanks full man, q when and if I get this part of the job i will put gauges on the system