1/4" lineset for 1.5-ton XL15i?

[outbacker]

Thanks to the great advice I received in this forum, I purchased a 1.5-ton Trane XL15i AC with XV80 furnace this past spring for my 500 sq. ft. upstairs bonus room. So far, it's been a great system, quietly cooling the room and keeping it much more comfortable than the previous 2-ton Carrier contractor-grade model we had.

My downstairs unit is a 9 year old 3.5-ton Carrier contractor-grade model that I may replace next year if I can get the tax credit again (I get the credit on the system I bought this year).

Anyway, while having my Carrier unit serviced this year, the technician noted that they would have used a 3/8" lineset for the new Trane XL15i whereas the contractor that installed the XL15i pulled a new 1/4" lineset. Since it is a 1.5-ton system, I think 1/4" is OK but I'd like to be sure. I assume that bigger would be better but is bigger necessary? The length is under 30 feet.

Is this enough info to confirm whether the 1/4" lineset for the 1.5-ton XL15i is sized correctly?

Thank you!

[RyanHughes]

4TTX5018A1000A
Line Size - (in.) O.D. Gas 1/2
Line Size - (in.) O.D. Liquid 3/8

I'll let the pros comment on whether it would be acceptable.

[outbacker]

Thank you, Ryan! I see that in the data sheet now (it's funny how you can find something once you know the answer).

I would like to know what the pros think about this. Is 1/4" OK or should I insist that they pull new a new 3/8" line?

[the dangling wrangler]

I feel like, if the connections at the unit are 3/8", then that's what should be used.

Some people will say you only loose a fraction of efficency. Well, if the engineers that designed the unit thought so,they would have downsized it to begin with.Just my opinion.

Unless the piping is impossible to get to, why wouldn't they have used the correct size? The cost is next to nothing, the first time around. Not the second.

[mark beiser]

According to Trane's piping software, which in the world of Trane equipment is considered the final word in any refrigerant pipe sizing question, a 1/4" liquid line is the recommended size for a 1.5 ton R-410A system, even if it is a crazy long 120' line set with 6 elbows and 20' of vertical rise.

Trane has always recommended using the smallest diameter liquid line that comes in under the pressure drop limitation for the refrigerant being used, because it makes for a more reliable system that contains less total refrigerant.

[BaldLoonie]

Next question: did they use the 1/2" vapor line called for? No, I bet they used 3/4"

[Mr Bill]

Next question: did they use the 1/2" vapor line called for? No, I bet they used 3/4"

John, I bet you remember when the old RUUD/Rheems never had anything but a 1/4" liquid line, ah the good old days when an a/c system could actually freeze you out of your home.

[outbacker]

Thank you for confirming this, Mark!

It does look kinda hokey with a 1/4" refrigerant line running into the 1/2" pipe on the unit, which is pinched shut around, and soldered to, the 1/4" line. I guess they provide 1/2" as a standard on all sizes of XL15i.

[Airmechanical]

It does look kinda hokey with a 1/4" refrigerant line running into the 1/2" pipe on the unit

you got something backwards there

hopefully, you meant the 1/4 inch line is going into the 3/8 line, if not we got problems



.

[outbacker]

I'm sure I'm not explaining accurately or clearly.

The 1/4" refrigerant line runs about 25' from the furnace in the attic to the XL15i outside. There is a short "stub" of a pipe sticking out of the XL15i that looks like 1/2" (it could be 3/8" but it looks like 2x the 1/4" line). The 1/4" line goes into this larger "stub" pipe and the "stub" pipe is squeezed around, and soldered to, the 1/4" line to make it fit.

I guess the contractor may have added the larger "stub" pipe as a coupling between the standard refrigerant hookup on the XL15i and the new 1/4" line that he ran.

[the dangling wrangler]

I'm sure I'm not explaining accurately or clearly.

The 1/4" refrigerant line runs about 25' from the furnace in the attic to the XL15i outside. There is a short "stub" of a pipe sticking out of the XL15i that looks like 1/2" (it could be 3/8" but it looks like 2x the 1/4" line). The 1/4" line goes into this larger "stub" pipe and the "stub" pipe is squeezed around, and soldered to, the 1/4" line to make it fit.

I guess the contractor may have added the larger "stub" pipe as a coupling between the standard refrigerant hookup on the XL15i and the new 1/4" line that he ran.

Pictures would help.

[Airmechanical]

I'm sure I'm not explaining accurately or clearly.

that's right

no math needed here

there are 2 stubouts on the unit outside, a big one and a smaller one

is the 1/4 liquid line "in question" going to the bigger one or the smaller one?


.

[outbacker]

Here's what it looks like: