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American Air Purger 443 - Are they every 1 1/4" Thread?

cwilliams2000cwilliams2000 Posts: 140Member
I have one of these and I am trying to relay the size to a contractor and trying to save a trip and will be replacing this with a spirovent. The copper pipe going into it is definitely 1.25" but the 443 has threaded ends and the fitting looks like the threads are the same size as the OD of the 1.25" pipe. When I look onlie they all look like 1" but I took a measurement of the threads (male) going into the 443 and they are about 1 5/8" OD. So I think this is a 1 1/4" thread.

What do you think? Thank you


  • icesailoricesailor Posts: 7,265Member
    edited March 2014

    It is a 1 1/4" thread. Why do you need to replace it with a Spirovent? Did yourself or someone decide that there was something wrong with the 442? What can go bad with it? I've installed many of them or same type. I've never ever changed one.

    Does it look like this one (hard to see). That one is over 30 years old. Its been through numerous air vents and a Extrol tank. Plus a boiler change.
  • hot_rodhot_rod Posts: 11,252Member
    limited air removal

    with a scoop type air removal device. Flow velocities need to be between 2-4 feet per second. You need a section of straight pipe upstream of the purger to allow them to work well.

    The microbubble type of air eliminators are designed to scrub large, small, micro, and entrained air.

    Best heat transfer, and system efficiency is only accomplished when all air is removed, even the stuff you cannot see or hear :)

    If you have a chronic air problem, a micro bubble type of device is a wise investments.

    Look for a valve or a device in the piping that is restricting flow, maybe a balance valve of any valve that is chocked way down, or an oversized circ.

    Either the system has never had a clean purge, or you have something going on in the system that is causing the air problem.

    Expansion tank location is also critical so you don't pull sub-atmospheric conditions that can allow air into to be drawn into the system, thru auto vents.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • cwilliams2000cwilliams2000 Posts: 140Member

    Yes the installer recccomended it since it seems that I can never get all of the air out of the system and some of it is quite bad. I have heard great things about the Spirovent so it didnt seem like too big of a surprise. All those little vents I Have ever had have failed and two of them squired water and in one case twice and shorted out my firing control which really sucked actually. I would be thrilled to get rid of them,
  • icesailoricesailor Posts: 7,265Member
    Leaking caps

    Because you or someone left the caps loose.

    Like I said in the beginning. That system is on the second boiler, the first installed in 1984. It has run continuously since then. Even when I changed the boiler, it never had a vent cap opened on a baseboard to vent it. Once purged, it ran continuously. Most of the 6 Taco zone valve power heads have been replaced.

    So again I ask, where's the air? Where's your air coming from? Spirovents are just a big float vent and if they start leaking, IF you can get them apart, you can fix them. But the easiest fix is a 1/2" coupling, a reducing ell and a 1/8" float vent.

    If you're getting air in your system, where is it coming from? If you're getting air, your system will fail from oxidation. Where's the air coming from?
  • hot_rodhot_rod Posts: 11,252Member
    dirt or debris in the system

    can also cause air vents to fail or seep. Consider a two in one device the separates dirt down to a 5 micron size and eliminates all the air.

    In critical locations I suggest adding a hygroscopic cap. This cap has fiber discs that swell if the float vent should ever leak. So a second level of protection against leaks. The cap can be added to most vents. These are commonly used on vents on radiant manifolds that are mounted in closets or other spaces where leak damage is not an option.

    Look for a vent that is easy to disassemble and clean and service if you have old piping or radiators that shed rust or scale that can cause vents to plug. Some brands have a cap that is hand tightened and can easily be removed to service the small "needle" valve inside.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
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