Boiler System Air Issue

[LibertyTree]

Hi Guys, we installed a Carrier boiler about a year ago and about 2 months after we got a no heat call. Came out and found that the system was full of air. The radiators have no bleeders. The return lines have spigots on them for bleeding. It was a straight change out with no funds available to re-do the piping. I bled all the air out which took 2 hours (no joke). Just got a call from the home owner again with the same issue. Somehow there is air getting into this system and the Honeywell Supervent is not getting rid of it. The old 50 year old boiler didn't have this issue. There was a shotty remodel done in the home, I'm wondering if they tied the domestic into the boiler lines somehow? Forgive me, boilers are not my specialty. Also, the Grudfos pump was set on Medium, I switched it to High in hopes that it might move the air to the eliminator better. Do you guys have any suggestions for me on this one?

[BaldLoonie]

Are you pumping away from the expansion tank/air vent?

[beenthere]

Looks like the vent is piped up to a bypass. Won't get rid of air too well that way. What temp is the boiler high limit set to, and what PSIG is it running at.

Are the rads old seam rads, that were converted over to hot water.

[beenthere]

Are you pumping away from the expansion tank/air vent?

Looks like toward them, and the circ is mounted in a position(motor up) that the system should be at 20PSIG.

[Joehvac25]

Check the exp tank to see if its water logged, other than that I really can't tell what's going on because my pics are so small on my phone. Mabe the messed with the system and now your stuck bleeding it, sometimes that air takes some time to dislodge.

[ch4man]

that is seriously ugly. your air problems are due to the near boiler piping.

i know its the customers money, but like it or not its now your job to convince him to either live with it or pony up and have it done right.

get Houlihans book pumping away. great book, can read in an hour. it will open you eyes to the difference between good, bad and ugly near boiler piping

[LibertyTree]

I believe its set at 125* and 20 PSI. I'm not exactly sure about the temp, I would have to look at it again. I don't even know what a rad is... A guy I had working for me did the installation.

[LibertyTree]

I know it looks like crap. It was either change out or lose the job which was clearly stated by the home owner. Why would the piping be causing air issues? Why did the old boiler work just fine with this piping?

[LibertyTree]

Yes, its tied into the supply side and all the water is not forced through the vent. There are 2 tees in the main supply that build this vent/expansion manifold. I was wondering how good of a job this configuration could do. Would adding another vent or re-doing this one help me?

[Joehvac25]

Do you have leaks anywhere? The tank is full it will lose pressure and take in air. Some systems are harder than others to get the air out. If you pump away from your air scoop the pressure drop will let the air out also. I would be looking for leaks or bad exp tank, air has to come from somewhere.

[Chuck]

Yes, it is the piping that is causing your air problems.

Read the book ch4man mentioned and pipe accordingly. You will not have air problems again.

[beenthere]

Yes, its tied into the supply side and all the water is not forced through the vent. There are 2 tees in the main supply that build this vent/expansion manifold. I was wondering how good of a job this configuration could do. Would adding another vent or re-doing this one help me?

All the water is to go through the vent. And of course it should be much bigger.

[Joehvac25]

Chuck and beenthere must have good eyes, everytime I look at the pic I feel like mine are going to bleed lol

[tinman]

maybe you could get a verticle air purger and install it coming out the supply side of the boiler then installl the pump above it in the verticle position. The pump is eventually going to go out installed that way but not vertically, look at the paperwork that comes with the pump. bring the expansion tank to the point of no pressure change at the air purger and tie in the make up water and you're set to go.

one thing to remember, when you do something cheap it still has to be right because it can and will haunt you and become more of a PIA. good luck

[Chuck]

For a system with one pump and multiple zone valves, and boiler bypass this is how it should be piped. PRV should be piped in at tank location. Purge valve between boiler and tank connection should be installed for air purging.

[Chuck]

Nobody caught my mistake??? I can't go back and edit it now.

I meant "system bypass" not boiler bypass. System bypass is needed when you want to keep the return water temp above 130 to eliminate thermal shock and flue gas condensation. A boiler bypass would have the bypass tied into the supply line upstream from the pump as opposed to downstream in my drawing.

Boiler bypass is used to control supply temps. System bypass is used to control return temps.

[Joehvac25]

Nobody caught my mistake??? I can't go back and edit it now.

I meant "system bypass" not boiler bypass. System bypass is needed when you want to keep the return water temp above 130 to eliminate thermal shock and flue gas condensation. A boiler bypass would have the bypass tied into the supply line upstream from the pump as opposed to downstream in my drawing.

Boiler bypass is used to control supply temps. System bypass is used to control return temps.

What do you think of this, no pump on boiler just out in system, keeps boiler temps high and system side low.
Not sure if you can make it out

[Joehvac25]

I didn't put water heater in

[firecontrol]

After I stepped away for awhile so my eyes would straighten back out my only suggestion is to bite the bullet and start over. I'm real suspect if the old boiler worked any better if it was connected exactly the way this one is.

[Joehvac25]

After I stepped away for awhile so my eyes would straighten back out my only suggestion is to bite the bullet and start over. I'm real suspect if the old boiler worked any better if it was connected exactly the way this one is.

He's right, the HO is always going to say it worked better before you were there because they don't want to pay.