Air conditioning service valve

A description of the design of the service valve used on air conditioning units since the early 90s. Leak problems and brazing are covered.
This video is part of the air conditioning series of training videos made to accompany my website: to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal and high pressures are used. Know your limits.

20 Replies to “Air conditioning service valve”

  1. Do you not just remove the plunger and valve core before brazing the service valve on?

  2. Recommend replacing the service valves due to over heating when brazing and cause the failure of o-rings. Bypass the service valves by add a new line with a schrader valve will work ? This is a cheapest solution and solve the problem of leaking service valves !

  3. and this is why I run water over the valve and purge with nitrogen while soldering service valves. And no water does not get in the system.

  4. Great information and video, as usual, but a diagram would be helpful here.

    The experienced guys can relate to this, but it's confusing to newcomers.

    Case in point: there are 2 openings, 1 is a Schrader valve. Isn't that the "service valve "? If not, what is the Schrader valve there for?

  5. Nice and thx. Is the seal at the top of the plunge? is it possible to vacuum the indoor unit/pip while keep the R410a inside the new condenser untouched?

  6. Nylog under the cap did fixed the problem for me. Both high and low pressure valves were leaking, about 2 lbs of r22/year. When they leak you can detect it with any halogen detector with the caps removed.

  7. is it still a good practice to wrap it with rags when brazing, or using something else and what?

  8. great vid. Goodman condenser installation instructions state to set it 1/8 inch from being fully open.

  9. GFM, thinking about the construction closely as you exposed it… something does not make sense. With the valve closed or front-seated fully it cannot be the o-ring that acts as a sealer between the lower pipe and upper pipe and schrader. It must therefore be a brass to brass seal that closes off the lower pipe when the valve is closed. Therefore, the only thing that makes any sense is that these are designed to be opened once when the unit is initially installed and the cap is meant to seal it afterwards. I don`t think they made these with any regard to servicing the unit with pump-down. They probably expect recovery as the only viable method to service the systems anyway. It is apparent that manufacturing engineers put very little thought into how these systems are actually serviced in the field.

  10. Why in the world are the new service valves made without retaining rings??? The style like you show you can replace the o-ring. The new ones are not serviceable. Once the O-ring fails you have to replace the entire assembly. It`s insane!!

  11. Usually its the suction side valve that starts to leak… of course being a bigger pipe it takes alot more heat to complete the brazing. Also, I understand your comment about warping the valve however I think the o-ring will melt way before the valve has a chance to warp.

  12. As a service guy, loves these calls, shitty installer didnt wrap the valve in a wet cloth, probably didn't take the schradders out either, generally see the blue junk (thread lock) around the cap. For the 2 minutes it would take to remove and wrap, would save the homeowner a lot of money, and the embarrassment for the installing company. If one of our installers did it, I'd send a vid to the installer and the service manager, practicality is great, laziness i hate.

  13. In a word NO!!! on the removal of gauge set under vacuum. First, evacuation with schrader valves in is like showering with a raincoat on. You need the easiest way possible for the gasses to get into the vacuum pump. If you remove the gauge set under vacuum you are guaranteed to lose vacuum. You can pressurize the lineset by cracking the liquid line to 5-10# PSIG, then install schraders under slight positive pressure. I will be demonstrating this in a video soon. Hope this helps.

  14. I've seem instructions on the web that say you can remove the vacuum hose after you have evac'ed the line set. Does the Schrader valve let air back into the system ? Wouldn't it be better to let the refrigerant pressurise the indoor unit and lines and then remove the hose ?

  15. You got it. It was set up that way for new installation so that you only had to evacuated the lineset and indoor coil.

Comments are closed.