Recharged house a/c, cools better but gauges still low.

[atikovi]

This is a 1990 Amana unit that I have to top off with freon every few years. Started using it a few weeks ago and it runs nearly nonstop without cooling much. It's about 70°F coming out of the vents when the house is at 78 and outside is about 85. This is the before shot of the gauges,

and the pressure chart with this unit on the right side,

It took about an hour to add 3 pounds of R22 and this is what the gauges looked like then, better but not the 80/236 psi on the chart,

and the vent temperature,

Much better but shouldn't the pressures be a little higher and the vent temp a little lower, like in the 40's? Why won't it take more R22? Tired compressor?

 

[CDX825]

You won't ever get 40 degrees out of the vents on a residential system. The evaporating temperature should be running between 40 and 50 degrees but your air temperature will never be that cold. You should be checking superheat too because to much refrigerant and you will flood back to the compressor.

 

[atikovi]

Ok I'll see if I can check the evap temp.

 

[bullwinkle]

Head pressure is pretty low for your low side pressure & temperature, compressor ever been replaced? Is it pulling the amperage (using an amprobe on the “C” or common terminal that it’s rated for (search using the compressor model # online)? A test I use on (refrigeration, non-A/C) compressors is temporarily disconnecting the condenser fan & see if the compressor gets up into HPCO range (~400 PSI high side)-if it can’t get there, it’s likely toast.

 

[WobblyElvis]

Basic rule with home ac is......the temp drop from return to vent closest to unit should be 20F +-2. So it's working very well.

 

[atikovi]

Head pressure is pretty low for your low side pressure & temperature, compressor ever been replaced?

If the compressor was replaced it would have to have been over 15 if not over 20 years ago.

Basic rule with home ac is......the temp drop from return to vent closest to unit should be 20F +-2. So it's working very well.

So house is at 78° and it's 55° at the vent so the temp drop of 23° is pretty good?

 

[97prizm]

This is a 1990 Amana unit that I have to top off with freon every few years. Started using it a few weeks ago and it runs nearly nonstop without cooling much. It's about 70°F coming out of the vents when the house is at 78 and outside is about 85. This is the before shot of the gauges,

View attachment 221021

and the pressure chart with this unit on the right side,

View attachment 221022

It took about an hour to add 3 pounds of R22 and this is what the gauges looked like then, better but not the 80/236 psi on the chart,

View attachment 221023

and the vent temperature,

View attachment 221024

Much better but shouldn't the pressures be a little higher and the vent temp a little lower, like in the 40's? Why won't it take more R22? Tired compressor?

Sounds like a leak somewhere. I don't think it should have taken that long to fill.

 

[WobblyElvis]

Basic rule with home ac is......the temp drop from return to vent closest to unit should be 20F +-2. So it's working very well.

So house is at 78° and it's 55° at the vent so the temp drop of 23° is pretty good?

Yes 23F is very good. But.....a small undercharge will tend to over cool as yours is doing now. This can lead to the evaporator icing up. As to why it won't accept R22 quickly, a guess would be the connection was not properly made. The valve core may have not been fully depressed or you didn't have a valve open all the way. Perhaps an HVAC professional will have some better insight.

 

[Cujet]

For your system to pull R22 from the can or the bottle, the source pressure (can or bottle) must be higher than the low side pressure. As the freon evaporates, it cools and the pressure drops. It is possible that the source was simply too cold for an adequate flow rate.

You could try dunking the source in a bucket of warm water.

 

[atikovi]

I have a wrap around heater but didn't bother swapping it from the r134 tank as this one was still half full. Next time.

 

[Donald]

This is a 1990 Amana unit that I have to top off with freon every few years. Started using it a few weeks ago and it runs nearly nonstop without cooling much. It's about 70°F coming out of the vents when the house is at 78 and outside is about 85. This is the before shot of the gauges,

View attachment 221021

and the pressure chart with this unit on the right side,

View attachment 221022

It took about an hour to add 3 pounds of R22 and this is what the gauges looked like then, better but not the 80/236 psi on the chart,

View attachment 221023

and the vent temperature,

View attachment 221024

Much better but shouldn't the pressures be a little higher and the vent temp a little lower, like in the 40's? Why won't it take more R22? Tired compressor?

I cannot imagine an HVAC tech waiting 3 hours to add refrigerant.

 

[Donald]

I would start saving $$ for a new one. It's now 34 years old. It will not last forever. You can replace it with one that's more efficient and a heat pump.

 

[WobblyElvis]

Make sure the air filter is good. Reduced flow over the evaporator coil can mess up the gauge readings.

 

[atikovi]

I cannot imagine an HVAC tech waiting 3 hours to add refrigerant.

Of course not, he would want to sell me a new unit for $8000 made with a Chinese components and won't last ten years.

 

[KJSmith]

HVAC techs generally charge as a liquid, not as a gas.
Goes much quicker.

 

[atikovi]

The manual says to charge as a gas.

 

[KJSmith]

45yrs as a HVAC mechanic. ( retired)
Graduated Tech school in 1977.

I know what the manual says.
I know what techs do.
A tech would have found out what was wrong before he finished.

Are you EPA certified?

 

[atikovi]

What are you? A cop?

What was wrong is that it was low on freon.

 

[KJSmith]

What are you? A cop?

What was wrong is that it was low on freon.

If you are not EPA certified, what you are doing is a federal crime.
If you were not aware of that before, you are now.

A HVAC technician is not supposed to go to a home and continue to add freon to a leaking unit.
That is the exact thing that the laws are meant to prevent.

You need to find and repair the leak...if there is one.
If you think our laws are tough....ask our Canadian friends about theirs.

Of course not, he would want to sell me a new unit for $8000 made with a Chinese components and won't last ten years.

You should think before you insult a whole trade group.
We can only sell what others manufacture.
Its like any other group, about 20% should be doing something else for a living.
About 10% of those are out to rip you off.

Most HVAC guys are honest.
We can make more than enough that way.

I suggest you hire a professional.
You are dumping a hazardous gas into the atmosphere.
That affects all of us.

 

[atikovi]

You should think before you insult a whole trade group.
We can only sell what others manufacture.

What I've found is they would rather sell you a whole new system rather than diagnose and repair the old one.