Poor line sizing?

[Sean Fogarty]

2008 goodman unit. They must have left the old line set, but figured I would get some feedback about the line sizing..

I wrote it up but whats your opinion??

[Wayne B. Wilson]

I would refer it Sean . It should be the same size. CYA

[Charley L. Bottger]

Why not tell tell it like it is the MFG requires the same size as the outlet of the unit can not be reduced as it reduces the efficiency of the unit by as much as a 1/2 ton going from 3/8 liquid line to a 1/4 inch

[Sean Fogarty]

See Charley,
I was paying attention.
ON top of the line, it was a 2 1/2 ton for a 2200 sf heated space.
40amp breaker and safety fuses for a max 20 on the compressor, and no drip pan or switch installed under the unit.

I just wrote up that both the sizing and the line set may not be sized properlyand should be evaluated. . The damn thing didn't work anyway so it will have to be looked at to begin with.

[Wayne B. Wilson]

For one reason Charley HI are not refrigeration mechanics . He did very well noticing the the line set. Good catch Sean .

[Charley L. Bottger]

Originally Posted by wwilson3

For one reason Charley HI are not refrigeration mechanics . He did very well noticing the the line set. Good catch Sean .

Don't have to be a mechanic just have to be able to use your eyes as much as I have preached that very item over the years. WEll Done Sean

[Wayne B. Wilson]

Yes Charley your post are great, I Meant most would not know to state the lost of tonnage . It was a good catch by the lad, I have to keep a Eye on this guy. LOL

[Rick Strand]

Great post Sean, this is the kind of stuff we can all learn from!

[Charley L. Bottger]

Originally Posted by wwilson3

Yes Charley your post are great, I Meant most would not know to state the lost of tonnage . It was a good catch by the lad, I have to keep a Eye on this guy. LOL

Yipper be careful or you will be carrying his tools

[David A. Andersen]

Okay, I am not disputing whether this should be called out or not…

However, I am not seeing the same thing in this picture (which may not be accurate anyway) as the rest of you.

If we start at the top right of the photograph we see what appears to be a 3/8 inch line. When we come out of the tape we see a reduced line size. It goes back into a 3/8 inch line.

The line going into the unit at the flair nut does not appear to be 3/8. I think under the next taped area, it is reduced again.

Don't be surprised if someone gives you some flak on this one. If so, just let it go.

There are calculations to determine line set size beyond what the equipment outlet size happens to be.

You can have an inlet pipe smaller than 3/8 of an inch but are required to install 3/8 inch refrigerant line from the condensing unit to the air handler because of certain circumstances.

You cannot arbitrarily oversize the line because it can be critical to have too much refrigerant in the system. Just as it is critical for it to be too small.

There are numerous adverse effects that may occur from excessive refrigerant. Air conditioners equalize in the off mode. Excessive refrigerant in the system they actually cause flood back to the condensing unit and when the compressor comes on, it will wash out the oil and the compressor.

Liquid refrigerant may end up in the suction line, and if the line is short you may slug the compressor and break something.

If you have a long line set and a high vertical rise, your compressor must work harder.

If your condenser is above your evaporator (not quite as likely in residential, but it does happen frequently) you may overload your compressor on start up.

Additional start capacitors and potential relays may be required. Solenoid valves may need to be installed.…

Another issue is that when we downsize the line and then we upsize the line. Changes in volume may cause a "change of state" of the refrigerant. It may flash off because of the volume differential which equates to pressure differential.

That small section of refrigerant line may actually become the metering device which will cause refrigeration effects to occur outside of the evaporator coil. This is what causes capacity reduction.

There are a lot of considerations. Let the powers that be figure it out.

[Charley L. Bottger]

All I see is a 3/8 flared line brazed into a 1/4 inch that appears to be the original I see this done occasionally here and it is not allowed by the MFG to decrease the outlet size of the unit. I make those calls and let the contractor dispute if he wants to. One phone call to the MFG is all it takes

[Sean Fogarty]

Originally Posted by dandersen

There are a lot of considerations. Let the powers that be figure it out.

I did just that. The unit did not even begin to work for me so it had to be looked at period. I basicaly said that the line and the sizing may not be correct and it could be evaluated when the unit is serviced.