Another AC won't cool below 80F Problem

[johndoe74]

I live in AZ and one of my Goodman 3.5 ton SEER 12 units (only 2-year-old) is having trouble cooling the rooms below 80F in daytime after running for at least 3 hours straight (outside temp 100 to 110F). Using a laser thermometer, the temp coming out of the vents varies from 64F to 69F. My attic has R30 insulation. I've just changed the filter, and cleaned the condenser coils outside my house.

When the tech came, here are some measurements he took:

Sub cool: 11F / 10F
Superheat: 5F / 5F
Low side PSI: 75 / 77
High Side PSI: 280 / 260
Compressor: 22.1 - 18.3
Condenser: 1.6 -1.1

He told me those numbers look fine, and all he did is changing the piston from size 74 to 78 (according to him this will increase freon flow), and 'flush' the system.

Anyway, those didn't help at all, and now I have to call them back and do more diagnostics. What else can I ask them to look into (besides duct leaks)?

[smokin68]

A load calculation....that system might not be big enough to handle what you want it to do. 80 degree indoor with 110 outdoor is a large difference.

[amd]

Did the system ever cool better than it does right now?

Measure the temperature drop accross the air handler; if it's significantly greater than what you're getting at the vents, you could have a leaky return air duct or sections without (duct) insulation.

[TAC Service]

If your room temp is 80 (return air) and the supply air temp is 69 that is only an 11 degree TD, if the unit was operating normally it would be closer to 20 degrees. Its time for somebody else to look at it.

[beenthere]

Hope he still has the old piston.

[iraqveteran]

Superheat of 5

[beenthere]

happens with dirty ID coils.

[skorepeo]

Hmmm! I flush a toilet or flush a radiator but changing a piston to flush an A/C

[tinknocker service tech]

Hmmm! I flush a toilet or flush a radiator but changing a piston to flush an A/C

yea didnt you know it all goes down hill from there

[johndoe74]

Hmmm! I flush a toilet or flush a radiator but changing a piston to flush an A/C

Sorry, perhaps I shouldn't use the word 'flush'. According to the work detail, it's a 'System Evac', which he told me if something is blocking the line, doing that might help 'unblock' it.

I went outside and check on my condenser unit, I see water droplets forming on the cold line running into the condenser unit, is this normal?

[iraqveteran]

Sorry, perhaps I shouldn't use the word 'flush'. According to the work detail, it's a 'System Evac', which he told me if something is blocking the line, doing that might help 'unblock' it.

I went outside and check on my condenser unit, I see water droplets forming on the cold line running into the condenser unit, is this normal?

Condensation is normal but you still need to have the system serviced and diagnosed properly.

Believe us when we say cheap is not the route to take when it comes to HVAC.

[skorepeo]

You need a good tech now quit with this guy and get a more experienced tech while your still ahead!!

I am not trying to bash but from what you say he sounds like a handy man!!

[iraqveteran]

You need a good tech now quit with this guy and get a more experienced tech while your still ahead!!

I am not trying to bash but from what you say he sounds like a handy man!!

You need to find a real tech before your system dies due to a bad tech.

It has happened many times before...don't let it happen to you too