Air Conditioning - A/C Died - Need Advice?!

:confused: I need some advice regarding my central a/c. My equipment is a 3.5 ton 12 seer Rheem Scroll condenser unit, 10 years old, compressor 5 years old.

Last week, my condenser stopped working. I pressed the reset button, but it shut off within 10 sec. So I called the a/c tech. He came (fairly quick), put on the guages, which he said showed a clog, as the blue dial showed 40 psi and the red dial (head pressure) quickly ran up to 400-450, & then the unit shut off. He recommended I change the filter/dryer, and also add a second one inside my house. He also cleaned the condenser coils.

As a side note, whenever the compressor shut off, it would make this grinding sound.

He came the next day, changed/added the filter/dryer, and told me that before he installed the second filter/dryer, he blew through the system with his mouth, and felt the air come out the other end (I wasn't home then). Next he vaccumed, and started filling the system with freon. He was able to get the blue dial until 40 psi, but not any higher(at this point the head pressure was fine). So he shut down the system and added freon without the compressor running, and turned the system back on. Now the blue dial was still at 40 psi, but the red dial (head pressure) shot up again to 400-450 and shut off. The tech guy called his friend for advice, and both agreed my compressor is shot, & I need a new unit. Since they don't make 12 seer any more, I would need to upgrade to 13 seer, and therefore would also need to replace my indoor coils (evaporator).

My question is, 1) Is there anything else to check before spending $2200 for a whole new system? and 2) If I need a new condenser unit, would I need to replace my indoor coils as well (i'm only upgrading the seer, not size)?

Sorry for the long post, but I could use any advice.

I believe there is a restriction in the system. You did not mention if the metering device is an expansion valve or a flowrater. Debris or a bad expansion valve could be the culprit.
High head pressure can also be caused by non-condensables (usually air) in the system. Was new freon used or was the recovered freon put back into the system?

Did the tech measure superheat (or subcooling if it has an expansion valve)?

Usually, worn compressors exhibit low head (high side) pressure and/or high suction (low side) pressure.

Good luck.

The service tech said there is an expansion valve, although he did say if there was a restriction, he wouldn't have been able to blow through the system.

Also, he used new freon.

I beleive he didn't measure for superheat/cool.

What do you think about getting a second opinion?

Get a second opinion. Blowing through an expansion valve with your mouth is not the way to test it for proper operation.

Try burning and washig your condenser coil. Have the condenser running. Use a propane torch keep it moving and run it along the coil. Shut it off and hose it out. see if the head goes down.