HVAC turns on, blows, but not very cool (freon never low)

4 years ago

Last year we had an AC tech come out to inspect one of our 2 units. The one unit blows cool air and it's unmistakable that it is working well. However, the unit in question blows air but it's just not that cold.

After checking the freon it was fine, and he presumably inspected the attic portion and nothing to note. He said the coils outside were dirty and proceeded to wash them off with a wand. It definitely helped. But this year now, it's the same thing -- AC goes on, but cooling is weak.

So a few days ago I clean the coils with water and Simple Green. It seems to help a little, but things just aren't "cool cool". For example, yesterday the unit ran all morning and day, but the thermostat rose from 70 to 73 or 74 by the evening.

Next, I went in the attic to check things out. I didn't see anything egregious but there is an exhaust pipe area with PVC that has a rusted base area. This area blows out cool air although is that a problem? The PVC pipe is uncapped and seems to be the way it is supposed to? But there is a cap nearby just sitting there. Should this hole be patched closed somehow?

The other thing is this fan doesn't turn on while the cooling is on. I don't know if that means anything though. Maybe it's part of the heating portion? I went up again today and this fan is not spinning.

Also, I changed the filters less than a month ago.

Any advice?

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Comments (8)

PRO
Austin Air Companie
3 years ago
It is probably a refrigerant related problem, there may be additional problems. The rust on the bottom of that Evap coil you show in picture 1 --- if it's that bad on the exterior of the coil I can only imagine how bad it is inside the cabinet housing.

Lot's of rust + not cooling well = (almost always) refrigerant charge issues.

You need to call professional licensed HVAC service, HVAC is not a DIY kind of project.

I service the Katy, Texas area.
tigerdunes
3 years ago
for OP...what is your thermostat setting...what is outside temperature...and what is your supply temp at several locations within your home???....what is age of your AC condenser?...
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Hello Kevinande - I appreciate your response. I called a new guy and told him exactly what I posted here. He recommended exactly what you had said. I'll tell you what he did and you can tell me what I may have missed. He came on Sunday 6/14 - He emptied/evacuated all the freon - Added a vaccum pump and let it run for an hour - Filled up new freon (R22). The one thing I missed was, he didn't weigh before and after. - He claims to have filled 9lbs freon (my condensor is outside and the lines run to the attic) After everything said and done, the A/C started, there were no bubbles displaying in the gauge, the pipe felt cooler not sweating, it definitely felt cooler than the normal warm air. When the A/C was turned on, the current room temperature displayed by my ecobee was 85 and the set range was 80, however the compressor ran non-stop for about 8 hours till I manually turned it off. It dropped from 85 to 81 but it couldn't bring it to 80. I notified the guy, he said to leave it running till it reaches the desired temperature, then it should cycle on / off as needed. It never hit 80 and I had to manually cycle it on / off. 6/15 - The next day, I let it run again, same thing, as soon as the outdoor temperature was 90, my AC kept running till I manually turned it on / off 6/16 - I decided to try something different, I put a fan towards my thermostat. When I did that, it helped bring the temperature down on the thermostat sensor and allowed the A/C to cycle on and off and maintain 80. 6/17 - I reached out to the guy who came on Sunday, told him what has been going on still. He said time to replace your unit. Other than that he wasn't willing to troubleshoot it further 6/17 - I called another guy who came and checked, said the freon is slightly low. He asked me to capture the temperature on the vents, return and thermostat. Vents - 80 and Return 83 and Thermostat 86 6/18 - The 3rd guy came and added 1 lb of freon this afternoon. The A/C seems to be cycling on and off however the fan is still pointed towards the thermostat. Does it sound like I need to swap my Ecobee? I've already reset it 2 times and didn't notice anything different.
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twintechhvac
3 years ago
Hi there, here are things you should double-check. If all else fails, call an HVAC expert to come look at your unit!

- Is your thermostat set correctly?

- Did you change your filters?

- Check to see if your condenser is dirty

- Check to see if there is a refrigerant leak

- Is there a leak in your ductwork?

Best of luck to you,

Twintech Heating & Cooling

https://twintechheating.ca/
sktn77a
3 years ago
"fan doesn't turn on while the cooling is on"

What do you mean by this? Inside fan (presumably) or outside condenser fan? Either way, you not going to get any cooling without an air handler or condenser fan moving.
zone 8a no longer SETX
Original Author
3 years ago
Thank you for the replies so far. I thought my reply went through the other day, but this forum just doesn't work great for me for some reason. I lost my original post a couple times as well! I'll try again.

what is your thermostat setting...

Set to 70 mostly now.

what is outside temperature...

It was mid 80s lately

and what is your supply temp at several locations within your home???

....what is age of your AC condenser?...

I believe it is 15 years old, possibly more

- Is your thermostat set correctly?

I think so?

- Did you change your filters?

yes, within the last month/weeks

- Check to see if your condenser is dirty

The outside fan thing? Yes I cleaned it using Simple Green, but I will do this again

- Check to see if there is a refrigerant leak

We had it checked a few times in the last few years and it never even needed a top off, we haven't had the freon checked since last summer however.

- Is there a leak in your ductwork?

I went up there and looked around and did not find anything egregious other tham mentioned in the original post. THere is that rusted area that concerns me. And the main unit was leaking quite a bit of air from the duct to the main unit, and I tried to use HVAC tape to stop it up.
klem1
3 years ago
You origionally asked "Any advice".

Yes. #1 Get your money back from the tech that looked at it last year and #2 Stop surfing the net looking for the solution.

You hire a tech to tell you what's wrong,not things that are not wrong,take your money and leave you with the problem. As far as asking strangers on the interweb,the finest tech on earth can't tell you what's wrong,much less how to fix it. Folks mean well when they try and help you but if you knew or find out "how's your A,B,C and D",you would need to have some training in hvac. Worse than not knowing how things operates is trying to fix things if you don't know how they operate. So that you don't think I just came here to shame you,I will 100% answer two questions you asked. That little fan in your picture only run's when gas heat is running. The air leaking around pipe where case has rusted isn't enough to effect cooling by more than 0.001% and certainly doesn't indicate a refrigerant charge issue. I wish you the best of luck and if you ever want to commit to twice a week online hvac learning for 6 months,I believe we can help you learn to maintaine your system and decide if you want to apprentice for hvac repair training.
zone 8a no longer SETX
Original Author
3 years ago
I appreciate the candor, but I'm just trying to make the best of the situation. I probably won't ask that same company back but at the end of the day I have 0 assurance the next person is any better. So, that's why I'm trying to do what I can.

(For example, when we first moved into the house the end of the duct was completely cut off, and the home inspector never saw it!)
klem1
3 years ago
I feel your pain. I've been shafted a few times and I supposedly know my way around the building trades. You truly don't have assurance when hiring help but track record,aka reputation will go a long way in choosing quility people.

HVAC turns on, blows, but not very cool (freon never low)

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Austin Air Companie

tigerdunes

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HVAC turns on, blows, but not very cool (freon never low)

Comments (8)

Austin Air Companie

tigerdunes

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sktn77a

zone 8a no longer SETXOriginal Author

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zone 8a no longer SETX
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