Whats the problem?

[Sean Fogarty]

2 side by side units for a duplex today.

The upstairs one was checked first.
70 deg out of most vents with my temp gun.

The upstairs unit was struggling to keep up.

"Thats funny" so I turn down the a/c thinking just a little more load.

"Still not working right, and still 69 to 70 deg" "78 off of the return" I go out and grab the compressor suction line. "cold as ice".

Now what??? I check the tag, and it was sized just right.


I go back to the furnaces and "oh there is the problem!!!!"

Can you spot the problem?

[Jeffrey R. Pope]

Are you referring to the reduction in the high pressure line?

[Sean Fogarty]

Originally Posted by jpope

Are you referring to the reduction in the high pressure line?

You know the answer. Stop spoiling all the fun.

and yes it was about 130 deg to the touch..

[Bruce A. King]

That reduction is not going to make it as bad as you found it.

Look at the crimped/damaged spot a foot down the line from the reduction.

[Charley L. Bottger]

Originally Posted by sfogarty

2 side by side units for a duplex today.
"Thats funny" so I turn down the a/c thinking just a little more load.

Hey big boy what are you saying here if you turn down the stat it will put more load on the unit or perhaps your thinking it makes the unit get colder by turning down the Stat
Now that is Really FUNNY we need to talk

[David A. Andersen]

A reduced line will not get hotter, it gets cooler.

The suction line will not be cold if there is a liquid line restriction.

130 F is a dirty condenser coil (even if it looks clean)...

So what was the question?

[Sean Fogarty]

Originally Posted by cbottger

Hey big boy what are you saying here if you turn down the stat it will put more load on the unit or perhaps your thinking it makes the unit get colder by turning down the Stat
Now that is Really FUNNY we need to talk

Wow Charley, thanks for ridiculing me on the board.
If you want clairity since i was not techinical enough for you, I thought that it may have been at the end of the cycle where only the fan was still running and turning the air down would have started the compressor again.
Sorry I can't be an expert like you.

You should be happy a dumb inspector like myself actually discovered the unit had this problem and it was not cooling properly..

[Sean Fogarty]

Originally Posted by dandersen

A reduced line will not get hotter, it gets cooler.

The suction line will not be cold if there is a liquid line restriction.

130 F is a dirty condenser coil (even if it looks clean)...

So what was the question?

I thought the reduction was causing the unit to run constantly, therfore not being able to cool enough.
The copmressors were not dirty looking BTW. How much do you think a line that reduced woul lower the tonnage? The unit was a 2 ton.

[Charley L. Bottger]

Originally Posted by sfogarty

Wow Charley, thanks for ridiculing me on the board.
If you want clairity since i was not techinical enough for you, I thought that it may have been at the end of the cycle where only the fan was still running and turning the air down would have started the compressor again.
Sorry I can't be an expert like you.

You should be happy a dumb inspector like myself actually discovered the unit had this problem and it was not cooling properly..

Hey I am not ridiculing you just having a little fun with you thought Wayne had taught you better than that the way you made your statement was kinda funny made me laugh anyway. Lighten up you take every thing a little to serious.

That down size in the refrigerant line will reduce that unit approximately 1/2 ton.

I am happy you discovered the downsized line I have put pictures up of that very item at least twice on this board and some thought it was frivolous. Those kind of finds separate the real home inspectors from the desk jocks or wanta be inspectors

[Wayne B. Wilson]

Little grass hopper can be mean Charlie lololol

[David A. Andersen]

When sizing liquid refrigerant lines; it's liquid refrigerant and oil mix completely, velocity is not essential for oil circulation liquid line. The primary concern in liquid line sizing is to ensure a solid liquid had the refrigerant at the expansion valve. If the pressure of the liquid refrigerant falls below its saturation temperature, a portion of the liquid will flash into vapor and cool the liquid refrigerant to the new saturation temperature. This can occur in a liquid line if the pressure drops significantly due to friction or vertical left.
Flash gas in the liquid line has a detrimental effect on system performance for several reasons. It increases the pressure drop due to friction. It reduces the capacity of the expansion valve. It may erode the metering device components. It also causes erratic feeding of the liquid refrigerant to the evaporator which reduces its capacity.
So long as the refrigerant that reaches the metering device is properly sub cooled below its saturation temperature there is generally not a problem associated with liquid line sizing.
Liquid line pressure drop causes no direct penalty in power consumption and a decrease in system capacity due to friction losses in the liquid line is negligible. Because of this, the only real restriction on the amount of liquid pressure drop is the amount of sub cooling available.
The design of refrigerant piping is a series of compromises. The effect of sizing a liquid refrigerant line is a compromise between restricted flow and too much refrigerant in the system, both of which adversely affect its performance.
Unless you are prepared to compute the performance of the HVAC system by using the hundreds of charts available, simply calling out a refrigeration line that is smaller than the input line of the evaporator coil is just another "wild *** guess " that home inspectors should keep away from.
The reason that the unit is running constantly is because of the latent heat in the air we are experiencing this week! The unit is undersized because it was not designed for 100° outdoor air temperatures.
As I said, regardless of what the condensers look like, they can be dirty even though they look clean. The ultimate identifier for the home inspector is a hot liquid line.
The only time that the liquid line will become hot other than a dirty coil is if there is not enough refrigerant in the system. Refrigerant passes through the system too rapidly and does not have time to properly sub cool. In this case the suction refrigerant line will not be cool ( as you described).

[Charley L. Bottger]

As you know it will usually void a MFG warranty if one decreases the size of the liquid line from what the MFG intended by the size of the stub out. The problem is the old units that used a 1/4 inch liquid line are now being replaced with new units that require 3/8 and contractors are not updating the liquid line I see it quite frequently and IMO every HI should call it out

[Sean Fogarty]

Originally Posted by cbottger

Hey I am not ridiculing you just having a little fun with you thought Wayne had taught you better than that the way you made your statement was kinda funny made me laugh anyway. Lighten up you take every thing a little to serious.

That down size in the refrigerant line will reduce that unit approximately 1/2 ton.

I am happy you discovered the downsized line I have put pictures up of that very item at least twice on this board and some thought it was frivolous. Those kind of finds separate the real home inspectors from the desk jocks or wanta be inspectors

I'm sorry Charlie you just got my panties in a bunch.

[Jae Williams]

Originally Posted by sfogarty

You should be happy a dumb inspector like myself actually discovered the unit had this problem and it was not cooling properly..

Determining that the unit was not operating properly indicates that you are not "dumb"...rather it shows that you did your job well.

It is not the deign of the Home Inspector to determine why a defect exists nor how it should be repaired--unless you wish to step in a certain pile.

If HVAC is not your buttered toast--recommend an expert.

Ain't nobody what knows everything (except maybe me) so don't feel bad about recommending experts.

[Charley L. Bottger]

Originally Posted by sfogarty

I'm sorry Charlie you just got my panties in a bunch.

That is fine no problem do you wear pink ruffled panties or just plain panties