Outside Unit Carrier Central Air Conditioner Model 38CKC042-340 Inside Unit Carrier Furnace M/N : 58STA090-10116

I am very newb, i have no idea if there are other parts involved besides the above mentioned. So please let me know if i need to check for other parts

My Outside Unit is old and i have cooling issues, possibly even freon leak and this unit is just old

  1. So if i want to go from R22 to R410A do i need to change my inside Unix Carrier Furnace as well?
  2. If my furnace can stay the same, Can you suggest compatible Air Conditioners that would work with my Inside Furnace? I am just looking high level guidelines so that i can start researching on cost etc?
  3. Are evaporator coils part of the Furnace?
  4. Or it would be cheaper to just change the whole thing inside/outside? Does that involve just changing these two or all pipes etc between my inside outside unit would have to be changed?


1 Answer 1


Since you're changing refrigerants, it's recommended to replace the condensing unit (outdoor unit), all the copper refrigerant lines, as well as the evaporator coil (inside the furnace).

It's possible to keep the copper refrigerant lines, though it will require a bunch of extra work. And even still, not replacing the lines can reduce the life of the new unit.

Depending on the new evaporator coil, it may be able to be fit on the existing furnace. However, if the furnace is old and inefficient, it's a good time to consider upgrading to an efficient unit. The evaporator is not part of the furnace, though it's typically connected to it. So it is possible to change the evaporator, without replacing the furnace.

  • How can I find out if my existing evaporator could are compatible with R410a I was told by Hvac guy that they are but I would like to confirm myself ? Do those have some model etc?
    – SeanClt
    Jun 18, 2016 at 0:35

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