AC Not Cooling Well

[LowSL2]

I have an older HVAC system in my house. I'm assuming it's the original system, so we'll say it's 40 years old. We've been going through a heat wave the last week or so with outside Temps above 100 degrees. My AC will run non stop and will not cool lower than 77 degrees. Last year it would have a hard time cooling below 74 (I think). It seems like every year it's getting gradually worse. I'm not an HVAC guy, but I have checked the basics. I have a new air filter. Air flow out of the vents is good. The outside unit is running. The fan runs well and is pushing air through it (I think the blades might be a little low on the motor shaft and not pulling enough air, but it's always been that way). The air coming out is hot. The compressor sounds good to me. No unusual sounds coming from it. And when I touch the suction line at the condenser, it's cool. The discharge is really hot. And if I touch the suction line at the evap it's cool. And the discharge is hot. This system uses R22 so I don't have gauges to check it, so I don't know what pressures are.

What does this sound like to you guys? I'm not replacing this system because I don't have the money to do it. It needs to hold on for a few more years until I can afford it. I'm hoping it just needs a charge or something. I'm hoping to learn a few things from this so I can expand my knowledge.

Thanks

[DaleCaskanette]

May be a little low on gas   suction line should be about the same temp as a cold can of beer and should sweat on a hot humid day.  the only other thing i can think of is A coil in furnace plenum needs cleaning   More than likely needs a top up with some leak stop.  i dont know what it is like in us but but in canada we can buy it at the hardware store.  Temp of suction line should be about 40 degrees.

Silly question but did you wash out the condensor?? 

[LowSL2]

Suction line is definitely not as cold as a beer. And I've never washed the condenser. I'll have to peel back the steel to see what the evap looks like.

[domain]

Throw your fridge gauges on it? Probably dirty condenser

[LowSL2]

I don't want to risk contaminating the system with my R134a gauges. I'm going to see if I can borrow my friends. 

What is the general concensus on cleaning condenser coils? Compressed air?   

[AJ]

garden hose.

[domain]

Clean condensor from inside out. Dude get out of here with that contamination stuff. please lol

[LowSL2]

Clean condensor from inside out. Dude get out of here with that contamination stuff. please lol

I hosed out the coils.. I'm going to guess the last time it was cleaned was during the Clinton Administration.... Air flow through the unit has increased substantially. But, if I touch the suction line, it's cool. Not cold. Outside ambient is 83. Temp inside is 77. Temp at the nearest outlet vent is 53. Suction line temp at the evap is 60. Forehead is 92. Beer is 43.

I'll connect my gauges tomorrow when it's daylight. I'm guessing i go off of the chart on the unit as far as pressures go?

Thanks for the help everyone. I love learning new stuff. 

[domain]

Look up superheat/subcool on youtube

[sarjushah]

i think you really need to hook up your gauges to see low and high side pressures.

[LowSL2]

I had my friend who does HVAC come over and check it out. We compared pressures to the chart on the unit and they were spot on. He did say that on a 100+ degree day it's going to be hard to cool lower than 80 degrees in the house. After several beers we concluded that there's nothing wrong with the system and all I had was a dirty condenser.

Thanks for for the help guys. 

[tinasingh]

First thing is that you have to buy the best air conditioner. If you buy low-cost temporary AC then this type of problem will definitely come and if your air conditioner does not cool, the compressor might be defective. The compressor is a motor which compresses the refrigerant or coolant and circulates the refrigerant through the evaporator and condenser coils. If the compressor goes bad the cooling cycle does not start and the AC fails to cool. To avoid such problem next time buys from best air conditioner shops rather than any local shops.

[dennispalmer]

Compressor is an essential part of an air conditioner and it is responsible for cooling issues in the air conditioner. If your air conditioner is struggling with cooling issue then the compressor might be defective because it circulates the refrigerant through the evaporator and condenser coils.

[Jonhb87]

Numerous factors can cause your air conditioning system to stop cooling your home, but these are the most common:

Improper Installation
Unmaintained Condenser Unit
Insufficient Airflow
Electrical Issues
Thermostat Issues
Frozen Air Handler
Low Refrigerant