question about an hvac upgrade..what size liquid line do I need if I upgrade to a 16 seer ac from my current 5/8" line?

i currently have a system that's about 22 yrs old and approximately an 8 seer unit. i was told today that i'd have to have at least a 7/8" suction line if i upgrade any higher than a 13 seer unit.
  5 answers
  • The size of the system along with its length of run is what determines the size of the suction and liquid line. Nothing to do with Seer rating. Although that will be part of the formula the manufacture requires proper sizes to deliver the amount of gas needed to achieve its proper capacity. . If your upgrading your old R-22 system its best that you change out both the suction line and liquid line as the old refrigerant oil is not compatible to the new systems and their refrigerants. The cost can be quite high to flush out the old pipes and be sure their clean. Its best to change it all out.

  • Scott R Scott R on May 29, 2012
    both lines are in the walls behind solid drywall etc. i don't think replacing them is the best option from a logistical setup. i guess new lines could be run outside the house, but that's not an ideal situation.

  • Scott it never is an ideal situation. If the HVAC guy understands how to do this, and has worked on installs for any length of time, he or she knows how to hide these pipes easily. For many years and still now, we use a white leader pipe like the ones used on your gutters. We rip the seam open from the back with pliers and wrap the pipes with it. Then with a few small straps it covers and protects the pipe. It blends in quite well with everything else. They do make special covers that are removable and such, but once the pipes are on the wall, there is no reason at all to open the covers back up, so its really a waste of money for the owner. At least that is my opinion on this.

  • Plumber26 Plumber26 on Jun 08, 2012
    I think it should be code that when they build a house, they should have some sort of "chase" that linesets, condensation drains, drains for pans and gas piping can be accessed and replaced with no issue to the upstairs unit. We run into this problem with water heaters as well. New code does not allow PVC to be used as discharge piping from drain pans under water heaters. So any time we have a water heater in an attic, we have to run the 1'' CPVC drain from the pan, down the side of the house. And keep in mind, most homes that have a water heater in an attic, at least where I live, are nicer homes so customers do not really get excited about having to do this.

  • I too would love to see that, but its not going to happen in our lifetime. With the cost of square footage going up all the time, they are stealing more and more of our valued wall chases to do just that. And add to that open concept trend.. Its up to use to become more creative to do this.