R410a liquid line replacement req and sizing

[jgerken]

Hello gents,

I'm replacing an upstairs residential R22 Trane heat pump with a new R410A Trane XR13 2.5 Ton with a matching variable speed air handler. The current R22 installation has a 3/8" copper liquid line and I believe a 3/4" return installed.

In querying a number of different contractors on the need to replace the pipe, I got widely varied answers. Given R410a and its lubricant are both synthetic, unlike R22, it seems reasonable that they might not coexist well if the same pipe is used for the new installation. However, some contractors claim they can sufficiently evacuate the pipe. Others say that the liquid line size is wrong (5/8 copper would be proper) and so regardless it needs to be replaced with a vertical line run outside the house, but a subset of those say only the horizontal lines need to be replaced and using the existing 3/8 vertical pipe for the run from the crawl space to the attic is fine.

Some of this defies logic given the different boiling point temperatures and pressure requirements of the two. Trane surely has installation requirements and specifications for R410a referent lines, but I've not been able to find any definitive source for determining proper line size. Could someone please provide some insight or pointers to online documentation, procedures or specifications that could help me determine who is telling the truth, who perhaps doesn't know this stuff real well and who may be taking short cuts?

Thanks for your time,
John

[royc]

All those answeres are in the install manual that comes with every unit.

Roy

[skippedover]

All those answeres are in the install manual that comes with every unit.

Roy

Listen to royc he speaks good words. Part of the price of the equipment is a nice, multi-page installation manual with all kinds of instructions in it. I'll bet one or more of those pages address just the question you're asking. So have the contractor who wins the job show you in the manual where it says he can do what he's doing. If it doesn't say he can, well then..... Line sizing charts are in every install manual I've seen with new equipment. And I'm replacing the AC in my home this summer. Moving from R-22 to R-410A. Same line sizes required. I'll put in new refrigerant lines. Does that help?

[davefr]

You're probably paying hard earned money for a nice new R410A system. Why take shortcuts by trying to salvage some or all of the old lineset?

Unless replacement is totally impractical, just have them replace the entire lineset with a new/properly sized lineset that meets the manufacturers recommendations.

It's peace of mind at a small fraction of the cost of your new system.

[jgerken]

You're probably paying hard earned money for a nice new R410A system. Why take shortcuts by trying to salvage some or all of the old lineset?

Unless replacement is totally impractical, just have them replace the entire lineset with a new/properly sized lineset that meets the manufacturers recommendations.

It's peace of mind at a small fraction of the cost of your new system.

Hi guys,

Thanks for taking time to reply.

In general, I agree completely with all of you. My problem is I don't know who to believe. My inclination is to replace it based on my understanding of the physical properties of the two chemicals. But what I don't want to do is reward the bid to someone and then have to challenge them. I'd rather figure out who's being straight with me to drop those that are not and chose from the remaining set. Does anyone have a URL to the online manual for a Trane XR13? That would allow me to put this to rest and get about getting the new system installed from the best of the contractors I've spoken with.

Thanks again,
John

[beenthere]

One of the Trane guru's will be alone soon and they can tell you if you post model numbers, and describe the length of the run, as to weather your being stung along or not.

[andserco]

IMO- if you want a new line set, then insist on one....a new line set is excellent insurance for you and your contractor, on some installations, line sets are a PITA and add some pretty good expense to the job but worth it...

[davefr]

Hi guys,

I'd rather figure out who's being straight with me to drop those that are not and chose from the remaining set.
Thanks again,
John

I think you might be jumping to conclusions by assuming some of the contractors aren't being straight with you. There's more then one way to skin a cat.

R22 linesets can be flushed and reused for R410A. Even Carrier says this is acceptable however they also say it requires a proper flush. (the flushing chemical is expensive)

Most manufacturers spec the systems capacity at the recommended line set size. However there's a correction factor for length of run, length of rise and lineset diameters. The correction factor might not be an issue for your system.

Why don't you discuss lineset considerations with the contractors that make it to your short list. Any decent contractor should be happy to discuss their game plan with you and other options. Maybe the ones that proposed lineset re-use are looking after your pocketbook's best interest. If you're willing to dig a little deeper I'm sure they'd provide you with a new lineset - just ask before you waive a Trane manual in their face.

[AcDOCnTRAINING]

Others say that the liquid line size is wrong (5/8 copper would be proper) . FOR A 2.5 TON UNIT:confused:
What? look it up on the Trane Manual unless your runing over 300' of copper
or have a rise thats several stories high a 5/8 liquid line would be app.for a 10 ton unit!

There is a cleaner used called RX-11 its really just R-11 it can be shot in the line set it will clean all impurities including any residue of mineral oil left behind works great! Vac. system alone is NOT enough and nitrogen is not as good of a cleaner. Clean those line sets right or else the POE oil in your new R-410a system will,thats an excellent cleaner!:(

[kuryakin]

1. Use the line sizes recommended by the manufacturer. It's listed in the installation manuals for the units. Also, it has to be online at Trane's site, I would imagine. Also, a Trane dealer can tell you.
2. R22 is as synthetic as R410a. Agreed, the oils are quite different.
3. If you must use the same lines, there are procedures and solvents to purge the oil out of them so you can use R410a and POE or PVE lube oils.
4. 5/8" copper sounds WAY too large for a liquid line in a residential unit.


Hello gents,

I'm replacing an upstairs residential R22 Trane heat pump with a new R410A Trane XR13 2.5 Ton with a matching variable speed air handler. The current R22 installation has a 3/8" copper liquid line and I believe a 3/4" return installed.

In querying a number of different contractors on the need to replace the pipe, I got widely varied answers. Given R410a and its lubricant are both synthetic, unlike R22, it seems reasonable that they might not coexist well if the same pipe is used for the new installation. However, some contractors claim they can sufficiently evacuate the pipe. Others say that the liquid line size is wrong (5/8 copper would be proper) and so regardless it needs to be replaced with a vertical line run outside the house, but a subset of those say only the horizontal lines need to be replaced and using the existing 3/8 vertical pipe for the run from the crawl space to the attic is fine.

Some of this defies logic given the different boiling point temperatures and pressure requirements of the two. Trane surely has installation requirements and specifications for R410a referent lines, but I've not been able to find any definitive source for determining proper line size. Could someone please provide some insight or pointers to online documentation, procedures or specifications that could help me determine who is telling the truth, who perhaps doesn't know this stuff real well and who may be taking short cuts?

Thanks for your time,
John

[ClassicDave]

Hello gents,

I'm replacing an upstairs residential R22 Trane heat pump with a new R410A Trane XR13 2.5 Ton with a matching variable speed air handler.

However, some contractors claim they can sufficiently evacuate the pipe. Others say that the liquid line size is wrong (5/8 copper would be proper) and so regardless it needs to be replaced with a vertical line run outside the house, but a subset of those say only the horizontal lines need to be replaced and using the existing 3/8 vertical pipe for the run from the crawl space to the attic is fine.



Thanks for your time,
John



410A is more efficient so suction line piping may be smaller in certain installations, depends on the size(Tons) of the system, the length of pipe and the vertical rise or fall of the pipe.
You may also see a cooling capacity loss of the refrigerant when the suction pipe size is reduced and then that size line set is longer than it's 100% capacity rating.

I have the Carrier/Bryant Line Set chart burned in my memory but that's because 99% of my installs are with 410A refrigerant.

Sorry I can't help you with exacts on the Trane 410A systems, But I would recommend a 3/4 suction line for a 2.5 Ton Carrier/Bryant System that has a 50ft run because a 5/8 suction line would give you a 2% Cooling Capacity Loss at 50ft line set. Discharge Liquid Line would be 3/8.

[shoretrade]

Your line sizes are perfect for an average 50' or so line length.
Any traces of R-22 will be pulled out with a vacuum pump. The oil will not. If it's difficult to replace it, a proper flush is not a problem. If it's feasible to replace it, just do it and be safe. I would not hire that guy that said you need a larger than 3/8 liquid line. As others have said, you would need a really long run to make that true on a little 2.5 ton system. 410A is more efficient and you need less coil area to do the same as R-22.

I am a Trane dealer but this is pretty much universal with other units of the same size.

(Nitrogen will not flush the piping)