OT Any HVAC experts?

EzraBrooks

Moved into a new construction home and I came from the PNW where we never had AC.  I have one AC unit but two thermostats, one on first and second floor.  First floor is set to 74 and second floor is set to 75.  Last two days it has been 88 outside.  Unit runs 100% of the time from about noon on, and temp inside house creeps up to 76 by 7pm on first floor, but it is at 83 on second floor.  I always thought AC could handle outside temp - 20 so theoretically we should be able to hold 68 if it is 88 outside, yet we can't even hold 74.  Do I have an issue or am I expecting too much?  Thanks in advance.

Ozzie_Isaac

EzraBrooks said:

Moved into a new construction home and I came from the PNW where we never had AC.  I have one AC unit but two thermostats, one on first and second floor.  First floor is set to 74 and second floor is set to 75.  Last two days it has been 88 outside.  Unit runs 100% of the time from about noon on, and temp inside house creeps up to 76 by 7pm on first floor, but it is at 83 on second floor.  I always thought AC could handle outside temp - 20 so theoretically we should be able to hold 68 if it is 88 outside, yet we can't even hold 74.  Do I have an issue or am I expecting too much?  Thanks in advance.

May need to balance the vents.  If the builder never balanced the system you will need to throttle down vents near start of the runs and then open them as you get further away.

That way all rooms get the same airflow and theoretically all near same temp.  Lots goes into this, but that is the basic.

If you have two thermostats, is there an active damper system to control if you heat or cool ground floor or second floor?

Btw, when it is 105 here, my house is still 76, granted I have no humidity to contend with, but barely maintaining a 5 deg drop upstairs leads me to believe something is not performing as designed and needs adjusting

Gulfcoastguy

Have you changed the air filters?  Anything beyond that I have to call a serviceman.

EzraBrooks

Yes, changed the filters.  That is about the extent of my knowledge as well.  It is under warranty so might as well have someone take a look. 

lkapigian

Me thinks you have a charge issue ...

EzraBrooks

lkapigian said:

Me thinks you have a charge issue ...

Please explain?

lkapigian

EzraBrooks said:

lkapigian said:

Me thinks you have a charge issue ...

Please explain?

Refrigerate leaks are quite common, grab the Big Line going back to the outdoor unit, should be beer can cold....if it's warm it's low or a metering device issue, if it's iced over its an airflow issue 

lousubcap

I am about as far from any expert here but with two thermostats and one system and  the same ducting, how does this unit know "who's on first?"  
If fully charged (full of the latest allowed Freon) then your HVAC system is underpowered for your home.  Almost sounds like the build was designed for a second unit but you got shorted.  Take all with several grains of salt...FWIW-

EzraBrooks

@lkapigian looks like this is a problem, right? 

lkapigian

There you go, shut cool switch to off, fan on for a couple hours and let thaw....if it's low on charge it will rear it's ugly head again, if it was airflow from a plugged filter it will be OK

EzraBrooks

This is the second time it has happened so I believe it is low on charge as you predicted.

Gulfcoastguy

My parent’s rental house has two separate units, one for upstairs and one for downstairs. 

lkapigian

EzraBrooks said:

This is the second time it has happened so I believe it is low on charge as you predicted.

If so, based up the vintage, leak on the indoor coil especially if it's copper VS aluminum coil 

cookingdude555

Used to have freeze ups a lot on my system.  I finally opened up my system inside the house and cleaned the 'A' coil.  I had been using restrictive flow filters all in the name of better allergy protection, etc.  This caused my system to make up the air that was unfiltered anywhere it could through small cracks in the furnace.  It dirtied up the coil pretty good over time.  Once I got that really clean, I went to the cheap .99 filters.  Airflow is way way better now, and the ice ups are gone.  Like others have said tho, if airflow is not the issue, it is low on charge and I would call in the experts.

I cleaned the inside coil two weeks ago just for maintenance at the start of the AC season.  I have a wife and daughter with long hair, they clog more than drains ..

Coil before cleaning:


The nastiness:

EzraBrooks

Thanks @lkapigian you were exactly right.  Loose connection causing coolant leak.  Defective part has been ordered for replacement.  They filled us back up so we will be good until the part comes in on Monday.