Covert DX coil from R22 to R410A? 1

[carlosgw]

What are the issues with using R410A in a coil originally designed for R22?

My specific application is a 2 circuit 15 ton (2 7-1/2 ton) air handling unit coil.

 

[moideen]

just google, the lot of info and specification of r410A, high pressure refrigerant. system discharge pressure will rise above 600 psig. r22 system designed only to handle 420 psig...also there are differences in thermal properties....

 

[BronYrAur]

Concur with Moideen. I would replace the coil instead of just changing the refrigerant

 

[willard3]

If you replace the evaporator, you should also replace the condenser and compressor. too.

 

[BronYrAur]

Yes good point Willard3. I just assumed you were going to replace the condensing unit and piping and only trying to reuse the evaporator coil. Your filters expansion devices Etc would all need to be replaced as well. And as I recommended so should your evaporator coil.

I've done retrofits from R22 to r407c, which essentially just requires a good flushing of the oil. However, 22 and 410A are not compatible at all with the operating pressures. You really need a whole new system.

 

[berkshire]

If the system is old you might also look at the High side lines, if they have any corrosion , they may be marginal.
B.E.

You are judged not by what you know, but by what you can do.

 

[carlosgw]

I would replace the piping with the condensing units.
Do the expansion valves need to be replaced.
No idea on rating of the existing coil. What is the low side pressure for R-410a?

 

[moideen]

 

[carlosgw]

Thanks for the info.