R-410A Coolant Line Sizing

[Ryles]

We are getting quotes to replace our 23 year old upstairs AC and furnace. We are being quoted different brands but they are pretty much:

2 ton 15 SEER dual fuel system with 80% efficiency furnace with variable speed drive.

We are in the Atlanta area and the unit is upstairs so the 80% furnace should be fine as we don't expect it to fire very often.

My question is on the coolant lines. Some contractors say our current lines are fine and others say we need to replace them with larger lines.

Current lines are 1/2 inch and 1/4 inch I believe. Quotes that say to replace them have us putting in 3/4 inch and 3/8 inch lines.

Are the new larger lines necessary? The old lines are fine as far as condition goes, the quoted need is all about the size.

Ryles

[superd77]

how long is the current line??? if its very short you might be ok, but all manufacturers give recommended line sizes.

if it was mine i would put in the new lines!!

[Ryles]

The current line runs from the attic to the first floor and then about half the length of the house. So probably 20 feet down and then about 25 feet over. Say 50 feet total.

[dmaxbury1]

it needs replaced being that long especially with the use of r 410.

[beachtech]

it needs replaced being that long especially with the use of r 410.

no it doesn't

inles you like ugly lines running down the side of your house

[beachtech]

that vapor line maybe too small... but i have seen many 410A systems that have that liquid line acceptable for that length in that size

[beenthere]

Ask those contractors what size line set the install manual says to use.

[Ryles]

I will ask for the specs. FYI the contractor that says "replace them" is quoting a Lennox system and the one that didn't is quoting an Amana.

Either way there won't be lines runnning down the side of the house. Lines drop through an easily accesible chase to the basement garage and then out the side/end of the house.

[superd77]

the recommended line size for the lennox is 3/4 and 3/8.

do the right thing and have the right lines put in.

[vet]

I am a 30 yr tech in the A/C field but due to mobility problems ive been out of the loop for about 5 yrs now. Now i take care of a 296 apartment complex with electric carrier 1.5 ton to 2 ton systems, all are r-22 and refrig lines are from 1/4 liq line to 5/8 suction and the longest line sets are around 40 to 50 ft. Now the unit's evap coils are 25 to 30 years old, if you are able to keep the line sets that are there what about the coil's? Knowing they will need TXV's on them.

[beenthere]

Some what foolish to try and reuse 25 to 30 year old evaps over. Change them out too, but you can reuse the line sets.

[vet]

Thanks for the info on this, I did plan on replacing all evap coils just was not sure about the line set's.

[BaldLoonie]

I think some little Choo Choos call for 1/4 x 1/2" lines but probably not many will approve of them. Rheem doesn't mind 1/4" liquid line but not the 1/2. Goodman/Amana I've heard is OK with 1/4" too on small unit but again that 1/2. I'd rather have the right size lines running down my house in line-hide than hack onto the wrong sized lines. May work but undersized lines could be turning that pricey 15 SEER into a 12 SEER or something.