On Sunday, we got a call from one of our customers last year who asked a different company to come out and service their AC system since it wasn’t working. So, the company comes out and tells them they have a clog in the coil and the refrigerant is low. There is nothing they can do about it. They have to get a new system. Here’s the weird thing about it: It’s a 9-year-old air conditioner.
When she called us, I answered the phone and was delighted to hear she was going to give us a chance to come out and diagnose what the issue was. It sounded like she wanted a second opinion. When we got out there, we discovered her system was running, and it was even cooling fairly well at the moment. But, to her, that was not new information. That is what the system would do. If it had been turned off for a little while, it would run fine. The longer she ran it, like on these 100-degree Sacramento Valley days, the less it cooled.
Our technician Keith went out to the house in the Citrus Heights/Orangevale area. When he put his gauges on the system, he noticed a fairly low pressure on the suction side of the system and a pretty high pressure on the high side. This was strange because the house was warm. There should have been higher suction line pressures than what was showing. Keith let it run for about thirty minutes before confirming something was indeed wrong with the pressures in the system.
A measurement in the field we take often is called superheat and subcool. It’s a measurement of how much liquid refrigerant is in the copper lineset that runs between the indoor system and the outdoor system. Ideally, you’d like to see a balanced measurement of subcooling and superheat in the system. Too high or too low and it’s a sign that something is up with the system.
In this case, the subcooling was around 30 degrees. The superheat was around 35 degrees. Both were too high for this particular day because of the temperatures outside. Keith called me to confirm his suspicions. He had checked the airflow through the system. The return duct wasn’t crushed. The evaporator coil was clean. The filter was clean. All the registers in the house were open. But still, the pressure did not indicate a healthy system.
There is a device in some systems called a thermal expansion valve. It meters the flow of refrigerant into the evaporator coil. The evaporator coil is the “cold coil” that the air blows past to give you the cold air that runs through the ducts and into your rooms.
In this case, the expansion valve is not metering correctly and does not meet factory specs anymore. Simply changing this part out with another factory provided expansion valve will get this system up and running again. The owner of this house was super happy that we can fix her 9-year-old system for a fraction of the cost of a new HVAC system.
If you ever run into a situation where you are not feeling very sure about a company’s decision to spend your money, call for a second opinion. We saved this lady thousands of dollars by carefully pouring over this system. Looking inside the copper tubing and diagnosing how the system is running is a more professional and ethical way of treating our customers.
So, don’t stop believing in your HVAC system just because some company tells you to buy a new system. Almost everything on the system can be repaired if that is what YOU want to do. Make the technician repair if that is indeed what you want to be done.
For a free second opinion, simply show us the invoice from the other company you paid a service fee to and we’ll come out and happily make a thorough investigation on your system to give you the right answers. Call us at 916-877-1577 anytime!