AC not working properly

[check]

Hi, guys, I am having a central AC And I am looking for ideas as to what the cause may be. My AC unit is a Luxaire by York, and is hooked up to my propane powered Payne forced air propane furnace. It was installed in 2002 or 2003. (so the first question is, is it the older RS 22 refrigerant, or the newer stuff?)

In 2017, I had the capacitor replaced. The problem is when I call for air conditioning with the thermostat, the compressor unit does go on, but no cold air comes out, even though I can feel the Plenum being very cold. And the furnace fan will not come on, and if it does very little air comes through the registers. After he does on for a while I can see frost building up on the compressor.

If I call for heat using the thermostat, the burners come on, and then eventually the fan comes on but again very little or no air comes out of the registers.

Any ideas, guys?

 

[LouNY]

Check your fan switches and filters,
if your thermostat has a fan only function try that and see what you get.

 

[ray66v]

I would check to see if the A coil is frozen.

It may be hard to get a good look without creating a hole. But, some coil jackets do have a cover, or a place you can look inside.

If you look at the U bends on the ends of the tubes, there shouldn't be more than a couple of them with frost on them. If most, or all of them have frost, you may have lost gas, due to a leak.

If it is low on freon, when it freezes up, that would also reduce the air flow from the fan.

If it is frozen, it will thaw if you let it sit long enough. Then, you can usually run it briefly before it freezes again.

 

[Oaktree]

Given that you have almost no airflow in either heat or A/C modes, I'd look into some sort of duct blockage. Most FHA systems have dampers in the branch ducts, did they somehow get closed? Is it something simple like a filter that's really clogged?

 

[dodge man]

Blower motor?

 

[ning]

Given that you have little air flow with either the AC or the furnace, it sounds like you've got air blockage, and my bet is on the evaporator coils (of the AC - in a box just above the furnace) badly needing cleaning.

Have you regularly replaced or cleaned the air return filter for the HVAC? If no, or you don't have a filter, the probability for the coils being super dirty goes way up.
Cleaning them may or may not be simple, depending on how easy access is to the box the coil is in. In my system, i was considering having them cleaned preemptively, and the AC guy said it would be an all-day job because he'd have to empty the AC lines and disconnect them and that the system was running well within spec so they likely weren't dirty, despite the system being 24 years old (always filtered well). Some units have a panel that can be opened without disconnecting anything to access the coils, but ours is in a tiny closet with space at a premium, so someone made it easy on themselves to install... and ensured a future big bill if cleaning was needed.

 

[workinonit]

Blower motor issue.

 

[check]

Update: I left it off for quite a while, and then fired it up. It was working fine on the low furnace fan speed, but of course that wasn’t going to be enough to cool the house down. Interestingly, I turned the fan switch from “auto“ to “On“, and the fan did not come on right away but later did. I am wondering if there is some sort of delay function built-in to the manual “on” function for the furnace fan.

Anyway, It seems to be working fine all night. Will check the compressor again later in the morning to see if it has frosted up at all.

 

[check]

Further update: AC is still working fine, so my new theory is that the problem was simply a dirty return air filter on the furnace, thus limiting the air flow across the A coil in the plenum. (I replaced it.)

I still have an appointment next Wednesday with the service people, which I may or may not keep. And the fan “on“ switch still does not turn the fan on. But of course the fan still does go on high when needed with the AC on and with the switch turned to “auto“. (Our 8 year-old Payne furnace (which we installed in 2013 to replace the original 2003 Luxaire ) has a nice 2-speed fan system.)

The AC compressor is now 18 years old, since we did not replace it when we put in the new Payne furnace , and it uses the old R22 freon refrigerant. So, I need to try and figure out if it is a good idea to get a new one, perhaps more efficient? And I would really like to be able to figure out how much electricity would it would save to get a new one. In the summer, we spend $200 and even $300 a month on electricity up here.

 

[kenmac]

Just an educated guess. I would say the A coil froze (lack of air flow, or low refrigerant) causing the coil to freeze blocking off air flow... Leaving the unit off for a period of time allowed the coil to thaw, and resume air flow across the coil