Residential AC not cold

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marty   10 MW

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Residential AC not cold

Post by marty » Jul 22 2018 9:48am

Turn thermostat to Cool. Outdoor condenser fan spins. Furnace blower motor blows. See icy on copper line that's not insulated. See picture.
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furnace
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Outside lines are not hot or cold.
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condenser lines
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Things I tried. Clean water drain on furnace with hot water in garden sprayer and shop vac. Outdoor condenser was full of ghost farts. Please see picture of what is a ghost fart?
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ghost fart
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Cleaned ghost farts off with a water hose.
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condenser
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Put fan setting to On, and Heat, Cool setting to Off for 24 hours thinking evaporator coil might be frozen.

Still it's not blowing cold. What's broke?
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DanGT86   10 kW

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Re: Residential AC not cold

Post by DanGT86 » Jul 22 2018 9:53am

Typically when they get low on refrigerant they will freeze up the lines and the evaporator inside the house. You may want to do a pressure check and look for leaks.

The ghost farts, awesome term btw, and a clogged air filter will also drop efficiency and can lead to freezing on the lines but it sounds like you cleaned it already.

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fechter   100 GW

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Re: Residential AC not cold

Post by fechter » Jul 22 2018 10:20am

If you have ice on the evaporator return line, then it must be cold at that point. Maybe ghost farts on the evaporator fins? See if there is an access panel to get to the heat exchanger inside the duct.
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DAND214   1 GW

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Re: Residential AC not cold

Post by DAND214 » Jul 22 2018 10:26am

I know if the larger line at the condensing unit isn't ice cold, it need Freon. Never heard of the return line being cold. Always warmer than the suction side.

Dan

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spinningmagnets   100 GW

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Re: Residential AC not cold

Post by spinningmagnets » Jul 22 2018 11:51am

Always start with the easy stuff, even if the symptoms seem like it's unlikely. The rusty screen on the top of the pic shown is the exhaust flowing air in the UP direction. The air inlets are on the sides. Pull off the covers on the sides and clean all of the clogging stuff off of the fins.

Inside, change the air filter, do NOT use a HEPA filter (ultra fine filtering clogs too fast and too easily), use the cheaper ones and change them more often.

Run the fan 24 hours a day, regardless of when the refrigeration system is running (the compressor will kick on and off intermittently).

At that point, if it is still blowing warm, it is possible that you may be low on refrigerant. There is a dyed gas you can install that will help you see where leaks are when you wear special glasses (UV?).

Full disclosure...I am not an air-conditioning system technician, it is very likely I am full of crap. Do your own homework, and proceed after you have developed your own diagnostic and repair plan.

Harold in CR   1 MW

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Re: Residential AC not cold

Post by Harold in CR » Jul 22 2018 12:46pm

My Son is not an A/C tech either, but, he fixes them sometimes. He says 90% of the time, the Capacitor inside the cover on the outdoors cabinet goes bad. These are for starting the unit and you seem to have everything running, so, my guess is refrigerant needs attention. Youtube has many A/C video repairs.
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dustNbone   10 kW

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Re: Residential AC not cold

Post by dustNbone » Jul 22 2018 3:43pm

Either low on gas or the heat exchanger inside isn't getting enough airflow (dirty coil, dirty filter, vents restricted).

You should never see frost forming on AC pipes.

Leaks can be found fairly easily with a spray bottle and soapy water.

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TommyCat   1 kW

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Re: Residential AC not cold

Post by TommyCat » Jul 23 2018 7:58am

Definitely a refrigeration (R-22) problem. Call a tech in and have him confirm. Long shot would be if the RFC restrictor is plugged, but I suspect that it's almost out of gas or low. Have him find the leak with his TIF electronic leak detector (or equivalent). Should take less than 30 min. Refrigerant does not go bad, get old or need refreshed. It LEAKS out. Depending on where the leak(s) is found it's going to be your call whether to repair or replace the bad component. Get accurate and all inclusive quotes for repair/replacement costs. Something your going to have to think hard about as your 30 year old system is close to the end of it's life expectancy...


Still got a Pulse furnace under there? That's a new thread in itself. :lol:

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marty   10 MW

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Re: Residential AC not cold

Post by marty » Jul 24 2018 7:49am

Thanks all for the suggestions.
DanGT86 wrote:
Jul 22 2018 9:53am
Typically when they get low on refrigerant they will freeze up the lines and the evaporator inside the house. You may want to do a pressure check and look for leaks.

The ghost farts, awesome term btw, and a clogged air filter will also drop efficiency and can lead to freezing on the lines but it sounds like you cleaned it already.
Was going to check the air filter but I forgot. Don't suspect it is clogged. Been changing the air filters every year.
fechter wrote:
Jul 22 2018 10:20am
If you have ice on the evaporator return line, then it must be cold at that point. Maybe ghost farts on the evaporator fins? See if there is an access panel to get to the heat exchanger inside the duct.
Removed the tan panel behind the frosty line in first picture. All I see is more sheet metal. Yea no access panel unless I get the tin snips out. Don't think there are any ghost farts inside the house. Ghosts only fart outside.
DAND214 wrote:
Jul 22 2018 10:26am
I know if the larger line at the condensing unit isn't ice cold, it need Freon. Never heard of the return line being cold. Always warmer than the suction side.

Dan
Correct. Return line should be warm not cold.
spinningmagnets wrote:
Jul 22 2018 11:51am
Always start with the easy stuff. The rusty screen on the top of the pic shown is the exhaust flowing air in the UP direction. The air inlets are on the sides. Pull off the covers on the sides and clean all of the clogging stuff off of the fins.

Inside, change the air filter, do NOT use a HEPA filter (ultra fine filtering clogs too fast and too easily), use the cheaper ones and change them more often.

Run the fan 24 hours a day, regardless of when the refrigeration system is running (the compressor will kick on and off intermittently).

At that point, if it is still blowing warm, it is possible that you may be low on refrigerant. There is a dyed gas you can install that will help you see where leaks are when you wear special glasses (UV?).

Full disclosure...I am not an air-conditioning system technician, it is very likely I am full of crap. Do your own homework, and proceed after you have developed your own diagnostic and repair plan.
Re: Expensive pleated furnace filter. How to argue with customer when standing in the filter aisle at Home Depot? I always buy the cheap 50¢ filters. We are dealing with a guy who buys incandescent spot light bulbs. Heats his house with light bulbs and cools with AC :? Will tell him Spinningmagnets say.... buy the 50¢ filter. This is the upstairs heat and AC. Home owner only heats and cools one bed room of 5 bed room house. Marty said.... OPEN MORE VENTS UPSTAIRS.
Harold in CR wrote:
Jul 22 2018 12:46pm
My Son is not an A/C tech either, but, he fixes them sometimes. He says 90% of the time, the Capacitor inside the cover on the outdoors cabinet goes bad. These are for starting the unit and you seem to have everything running, so, my guess is refrigerant needs attention. Youtube has many A/C video repairs.
YouTube also has videos made by people like me who are AC wana be experts.
dustNbone wrote:
Jul 22 2018 3:43pm
Either low on gas or the heat exchanger inside isn't getting enough airflow (dirty coil, dirty filter, vents restricted).

You should never see frost forming on AC pipes.

Leaks can be found fairly easily with a spray bottle and soapy water.
Like the spray bottle and soapy water idea!
TommyCat wrote:
Jul 23 2018 7:58am
Definitely a refrigeration (R-22) problem. Call a tech in and have him confirm. Long shot would be if the RFC restrictor is plugged, but I suspect that it's almost out of gas or low. Have him find the leak with his TIF electronic leak detector (or equivalent). Should take less than 30 min. Refrigerant does not go bad, get old or need refreshed. It LEAKS out. Depending on where the leak(s) is found it's going to be your call whether to repair or replace the bad component. Get accurate and all inclusive quotes for repair/replacement costs. Something your going to have to think hard about as your 30 year old system is close to the end of it's life expectancy...


Still got a Pulse furnace under there? That's a new thread in itself. :lol:

Regards,
T.C.
Call a tech? That would be too easy.

Pulse furnace? What is a Pulse furnace? Those pictures are in a different folder.
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Lets stay let's stay focused and on topic here. Its hot outside. AC please.

Think next step is to open up the outside unit and look inside. What kind of AC gauges should I buy? Got auto gauges from the Any Auto AC Mechanics Here? episode. Happy to say car is chillen.

Are auto ac gauges same as house ac gauges? According to Google. Answer is No.
Can I use a auto a/c manifold gauge to add freon to my home HVAC

Hoping I will find a tag inside the outdoor unit telling me what type of refrigerant and pressures?
Last edited by marty on Jul 24 2018 8:04am, edited 2 times in total.
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fechter   100 GW

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Re: Residential AC not cold

Post by fechter » Jul 24 2018 8:01am

The fact that there is frost on the evap return line tells me the freon is getting cold enough but the cold is not getting transferred to the air inside the duct. I've seen where the evaporator coil gets iced up and air won't flow through it and it does the same thing.

Have you tried turning it off long enough to defrost the coil?

No access to the coil sucks. Like maybe you have to take the duct apart. Even if you could just find a hole up wind of the coil you might be able to shine a flashlight in and see the coil.
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TommyCat   1 kW

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Re: Residential AC not cold

Post by TommyCat » Jul 25 2018 9:35am

marty wrote:
Jul 24 2018 7:49am
Call a tech? That would be too easy.


I can appreciate the can do attitude :!: But a proper repair takes specialized equipment and knowledge, not to mention the time factor.
But If your set on it, let's continue.

Pulse furnace? What is a Pulse furnace?

The Pulse was the only Lennox high efficiency furnace that was manufactured at the time the A/C was, a some what off hand way to let you know I have experience in this field.

Lets stay let's stay focused and on topic here. Its hot outside. AC please.

Like a frikkin' laser beam! :lol:

Think next step is to open up the outside unit and look inside. What kind of AC gauges should I buy?


For a DIY not looking to do it for a living... something like this would do. Inexpensive set... Also get a digital temperature thermometer. And have a temperature/pressure chart for R-22 handy.

Hoping I will find a tag inside the outdoor unit telling me what type of refrigerant and pressures?

Post a picture of the unit tag on the outside condenser, it's on the side near the top. The refrigerant type will be R-22. A charging chart will be on the inside of the condensor service door.

Time to clarify some points...

"I know if the larger line at the condensing unit isn't ice cold, it need Freon. Never heard of the return line being cold. Always warmer than the suction side."

Of course ice cold is relative, and it's a good point about the freon. But the larger, insulated line should be cold enough to condense moisture. (sweat) But not cold enough to form frost or heaven forbid ice.

"Correct. Return line should be warm not cold."

The larger line is the return or suction side, and as such should be cold and sweaty. One of the reasons it's insulated.

Time to keep your A/C circuit diagrams handy. :wink: Like this one...

"The fact that there is frost on the evap return line tells me the freon is getting cold enough but the cold is not getting transferred to the air inside the duct."

The frosted pipe shown in the Ops pic is actually the inlet pipe to the evaporator coil and typically insulated. Tho technically on the low side of the refrigeration circuit. And just for fun, the evaporator actually removes the heat from the incoming air. Making the out going air cooler.


The issue of not enough air going over the evap coil to be the cause of the problem can be discounted...a dirty coil, bad blower, iced up coil, and plugged filter will certainly turn your A/C into an ice maker... but the ice will be everywhere. After the metering device, plugging the coil, and most importantly along the suction line back to the compressor. And when turned off water EVERYWHERE. Since the Op states...
marty wrote:
Jul 22 2018 9:48am
Outside lines are not hot or cold.
I assume when running...this could not be the cause of the problem.


Get your gages, hook them up. And do a quick static temperature/pressure check to see if you have any liquid left in your system...

A quick question before I go. Which is most accurate?

A) Worked fine till I turned it on for the year...
B) For the last few weeks or months the A/C seems to had to run longer and longer to keep up...
C) Boom, overnightthis happened...
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