RE: Constant Air in my boiler

bigboxofcrap

Hello everyone,

I have a Williamson boiler GWA 070 58k btu and I can’t bleed all the air out.  My unit is in the 5th floor approximately 500 sq ft unit.  I just replaced the circulator pump from taco 007 to the Grundfos UPS26-99FC 1/6 HP 115-Volt 3-Speed Circulator Pump.  I also changed the expansion tank and configured it to 15 psi.  A HVAC professional told me there was air in my system and the taco 007 circulator was not strong enough to push through causing an airlock.  He suggested If this grundfos does to resolved my problem, he would do a line test for leakage.  The problem is I can bleed the boiler for hours and there will still be bubble coming out of the water and I don’t understand how air can get in.  My question is if a line test necessary and if i setup a bleeder in my apartment would this resolve the problem?  Is there such thing as a auto bleeder so that I can set it and forget it sort of deal?  Attached is some photos.  Thank you all in advance!

neilc

so is boiler in the basement, and you're 5 floors up?
or is boiler on the 5th with you?

boiler pressure suggests it's in the basement,
if so you need a high pressure tank,
you need to match the cold boiler pressure,
which want to be 50~60 plus feet, the 25~30 psi the boiler gage is showing

what type rads on the 5th?
any known vents ?

Ironman

Do you se any leaks on the system? What type of radiators do you have?

The pressure on the gauge is at 30 psi which is the point where the relief valve begins to open. What’s the pressure when the boiler is cold?

Where are you trying to bleed the air from? Is the system actually air bound or do you get flow through the radiation?

There’s an automatic air vent on top of the air scoop. Is the cap loose so that it can vent.

What your “tech” told you about putting the larger ups26-99 on to push air through is totally bogus and that circulator is way over-sized for that boiler.

If the circuit IS air bound, proper valving and purging with system pressure is how air is removed. Once circulation is established, the air scoop will remove the rest over time if it’s functioning.

bigboxofcrap

Thank you Neilc and Ironman for your response!  The boiler is in the basement and the apartment is the 5th floor. The rads on the 5th floor are baseboard radiators, total of 3. No vents to air out on any of the rads. They used Plex tubing from basement to 5th floor. There is no leaks in the system which is why I am trying figure out why so much air constantly getting in the system. If I am not mistaken, it seems like it airlocks every 2 days, the air causing it to not to circulate. When this happens, the circulator pump gets very hot and boiler too. When this happens, I have to bleed it out to get it circulating again. The checked the air scoop, I depressed it and air was coming out than full water. This tech said his next best idea is to put purging valves on the rads upstair.

Zman

@bigboxofcrap
Can you post a picture of your boilers nameplate that shows the rated pressure as well as the tag on your relief valve? If the boiler is in fact on floor one, you should verify that the boiler can handle the pressure. The expansion tank should be charged to the operating pressure. In your case, if the system is 50' tall, the pressure at the boilers should be 50/2.31 = 22PSI + 5PSI (to prevent air being sucked in the top) = 27PSI

Because you are pumping into, rather than away from the expansion tank, the new oversized circulator is likely making the problem worse, causing the upper floor to see a lower pressure and possibly a vacuum. The circulator should be moved to the other side of the expansion tank.

bigboxofcrap

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bigboxofcrap

When I installed a single speed taco 007-F5, it was the same issue.  

bigboxofcrap

This is the baseboard in the 5th floor.  

Zman

If you move the circ and install a bleeder or air vent at the top your problem will be solved. I would put the 007 back or at the very least set the grundfos to speed 1.

Page 36 and 37 do a nice job of explaining the correct expansion tank location.
https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf

hot_rod

Look like the boiler is rated for 50 psi
I’d add a 45 psi relief valve, fill the system to 30 psi

Not a great air purger and it should have 18” of straight piping

I would replace that with a micro bubble type purger
.
Either move the expansion tank connection to where the boiler drain is above the pump
Ir move the pump downstream of the air purger, for “pumping away” benefits 

JUGHNE

Sometimes that auto vent you have on top of the air separator can allow air to be sucked into the system.
If you get the system to where you thing all the air is purged, then tighten the cap on the auto vent to see what happens......it is a free test BTW.

bigboxofcrap

Thank you everyone!  Can anyone recommend a tech that can assist?  I’m located NY and would like to know what I should ask them to do specifically.  Thank you again for your guidance.

Ironman

@JohnNY

Jamie Hall

All the folks have good thoughts... and @JohnNY is your man. The fundamental problem, though -- and he'll do something about it -- is that if you are on the fifth floor and the boiler is in the basement, there is not less than 50 feet vertically between you and the boiler. The static pressure of a column of water that high is 22 psi. This doesn't mean that the pump has to create 22 psi -- as has been noted the pump is bigger than need be -- but it does mean that in order to avoid a vacuum forming at the top of the loop and sucking air in the minimum operating pressure -- pump running -- at the inlet to the pump has to be at least that, and one usually likes to see a bit more -- say 5 psi more. 27 psi. The outlet of the pump, then, when it is running will be around 32 psi. And that's with the system cold.

And that is more than the pressure relief valve on your boiler.

This does not compute. The boiler is rated for 50 psi, and you will need a 50 psi relief valve. Furthermore, the expansion tank you have may be too small. It probably can be pumped up to 27 psi, but it will have less capacity to absorb pressure changes starting at that rather than the more normal 12 psi.

Intplm.

Besides all of the good advice that you should follow mentioned above. One thing that stands out with me is the fact that you mention that the air has always been a problem, Not always able to purge all of the air out, Etc.

What I would do first and for most is get rid of that air purger that is currently installed, and replace it with a microbubble air separator. This will remove most of, if not all of the air in your system automatically.

Do this first and most of your problems (air), will go away.

bigboxofcrap

Thank you all!  Is there any particular brand or part you recommend for the microbubble air separator?  Also, does anyone know John phone number?  Thank you again!

bigboxofcrap

Also, out of curiosity because I want to understand this better, how things work.  Why is the current air purger no good?  Thank you all again, I’m very grateful for you taking them time to reply.

Jamie Hall

bigboxofcrap said:

Thank you all!  Is there any particular brand or part you recommend for the microbubble air separator?  Also, does anyone know John phone number?  Thank you again!

646.598.7230 or 212.980.0909. The first number is @JohnNY wearing his consultant hat. The second is for him wearing his wrench turning hat.

JohnNY

Jamie Hall said:

The first number is @JohnNY wearing his consultant hat. The second is for him wearing his wrench turning hat.

How I would love to retire the wrench turning hat...
Alas, it looks like a few more years. Thanks for the referral, @Jamie Hall

Intplm.

bigboxofcrap said:

Thank you all!  Is there any particular brand or part you recommend for the microbubble air separator?  Also, does anyone know John phone number?  Thank you again!

"Spirovent" microbubble air separator. Is a good name. There are other good names out there as well.