9 year old 5-ton A/C problem.. please help?

Question

I have a problem with my 5 ton A/C. I replaced the broken fan motor with a new one and the A/C system began to work fine, but after about 5 minutes it stopped. Can someone please help me, is it the fan motor itself, which I highly doubt, or is it the compressor that has to be changed? Thanks.

BELOW IS MY LAST QUESTION PRIOR TO ASKING THE ABOVE...............

I have a 9 year old 5 ton commercial air conditioner on the roof but suddenly no cold air. The mechanic said compressor is bad but another guy said fan motor or the blade is the problem. Reason is the fan only gets half the hot air out of the building and the rest is left intact inside the building.

Can someone tell me if this is a reasonable explanation of why the A/C doesn't work? What's the life expectancy of a compressor?

Answer 1

Your 5T AC has these components:

The Compressor

The Condensing Fan

The Condensing Coil

The Evaporator

The Blower fan

In order for your system to remove heat, the compressor runs and creates a low pressure in your evaporator, and high pressure in the condenser. The compressor is the large can with the two copper lines running to it. Inside is a pump and motor. One of the lines (smaller one) runs to the condenser. This line will be hot, and as it runs through the condenser, the condenser fan cools the refrigerant. The cooled refrigerant flows to the evaporator. It goes through a small opening and then into the evaporator. The evaporator sits between the blower fan and the return air. As the air from your business is blown across the evaporator, it transfers its heat to the refrigerant, and the cooled air returns to the business. The heated refrigerant gas in the evaporator then gets drawn to the compressor.
If any one of these components does not function properly, the heat in your business will not be removed.
As the owner/operator of the equipment, you can do the following: Inspect the filter monthly and change when dirty. Inspect and clean the evaporator coil when it becomes dirty. Inspect and clean the condensing coil when it becomes dirty. Beyond that, you will need specialized training and equipment to diagnose and make repairs.
Verify that both the blower fan and outdoor fan are running.
If the compressor does not run, contact a reliable HVAC company and have them inspect and diagnose the unit.

Answer 2

5 to 20 years. A/C's are very complex.
Call a different repair man.