Wednesday, July 17, 2013

High Flow Access Valves

I ran into something this week that I was not aware of ; a new design access valve that works like a Schrader valve with a pin to depress, but allows 5x the flow of a normal Schrader valve. They are called Coremax valves by a company named FasTest. You can’t take these cores out with a typical valve core tool. I assigned a student the task of removing a core from a Carrier packaged unit, and instead, they broke the valve. However, it was not their fault, you can’t remove these cores with a typical core tool. FasTest sells a tool that will do the trick – for $189. Alternately, you can recover the charge and take the core and the assembly that holds it out with two wrenches, which is what we did. 

Important Safety Note
Do NOT take the valve apart without first recovering the refrigerant - you will get a face full of refrigerant!
It is easy to tell these valves apart from regular Schrader valves if you look closely. First, the brass fitting holding the valve is larger than typical Schrader valves. Next, you can see that the top part can be removed from the bottom with a wrench Finally, the head on the pin that operates the valve is larger than the head on a traditional Schrader. The advantage of these is that they open to a full 1/4” hole just by depressing the pin – so you get faster recovery, evacuation, and charging. The disadvantage is that if you want to take the core out for even better flow or if you need to change a leaky valve core, you need their $189 valve core tool. I don’t know how many other manufacturers are using these, but I found out Carrier has been using them on packaged units since around 2006. Here is a link to a web site explaining how these valves work and showing pictures. Coremax Valves
Here is a link to a Carrier Service Bulletin that was posted on
So a word to the wise - if your valve core tool does not appear to fit - maybe it doesn't. You might have a Coremax valve instead of a Schrader valve.


  1. Will the information about high flows be added to your book?

  2. i just read your post High Flow Access Valves and got too useful information that is really amazing.

    high flow valves

  3. Hello! I read your article it’s really nice. I like that you mention the safety points. It’s truly interesting and useful blog.