Minisplit A/C flexible hose

[Iceni John]

After struggling in vain all day trying to fit my Pioneer 12K minisplit's 25-foot copper lineset (1/4" and 1/2" with flare ends), I've given up:  it simply cannot bend enough to fit between the indoor and outdoor units without the copper lines kinking.   Unfortunately Parker Davis doesn't offer their new flexible lineset longer than 16 feet, so that's no good for me:  I need about 21 or 22 feet of lines.   Even if I can only buy bulk A/C hose by the foot, my local hose shop can put flare ends onto it for me.   My hose shop does have some 5/16" A/C hose in stock, but it's rated for only 300PSI, too low for R410a, especially if I'm using the minisplit's heat pump which increases the high-side's pressure even higher.

I have a vacuum pump, gauges, even a spare bottle of R410a, but I'm now stuck on what should be a straightforward part of the installation.   Grrrrr.

Has anyone here instead used flexible refrigerant lines for A/C systems in their bus conversions and RVs?   Is there a reason that the supplied lines are only copper?

Thanks, John 

[epretot]

Does the entire length need to be flexible?

Perhaps a shorter flexible line brazed to the end of the copper would work.

[mqbus767]

I used short flexible lines between the condensor and set of bulkhead fittings to allow my condensor to slide in/out of the original condensor bay. Not cheap, but they work well so far. If they were more affordable I'd probably use them on the evaps too.

https://www.supplyhouse.com/Rectorseal-68237-1-2-x-72-NoKink-Flexible-Refrigerant-Line-Connector

[Iceni John]

Does the entire length need to be flexible?   Yes!

Perhaps a shorter flexible line brazed to the end of the copper would work.
   No, unfortunately not.  there are too many bends all along its length for copper to work at all. 

[Iceni John]

I used short flexible lines between the condensor and set of bulkhead fittings to allow my condensor to slide in/out of the original condensor bay. Not cheap, but they work well so far. If they were more affordable I'd probably use them on the evaps too.

https://www.supplyhouse.com/Rectorseal-68237-1-2-x-72-NoKink-Flexible-Refrigerant-Line-Connector

If that were three and a half times longer, I would buy it.   Thanks for the link anyway!

John

[mqbus767]

I know it's not ideal, but why not use flared unions? I hard mounted bulk head fittings on angle aluminum. It worked pretty well for me.

How many evaporators are you installing? (Sounds like 2?)
Could you loop the line instead of doing hard bends? Most of the time, hard 90s are frowned upon in installations.

You probably already know this, but there is a minimum line set length as well as a maximum. 21ft is probably long enough. My condensor is in the middle of my (45') bus and the evaporators are on front/back wall.

I'm also assuming you're using a decent bender. I'm using this one: https://www.amazon.com/gp/product/B089MYQ5SV

They also make insertible mandrels. I think they are made of some sort of plastic. They allow you to free bend the copper without kinking it:   https://www.pioneerminisplit.com/products/lineset-bender-kit

[somewhereinusa]

I had really bad luck trying to bend the insulated lines without kinking. I was able to successfully use copper with lots of bends by cutting the insulation off  then putting it back on using zip ties.

[peterbylt]

I feel your pain.

It took me a while and I had to work the curves real slow, ruined the first set of tubes and had to get a second, also had to get a better quality flaring tool.

My original plans of some hard bends got changed to much longer sweeping curves, but I eventually got it done.

Maybe long sweeping curves are not possible in your case?

I had to make a few changes to the interior design to accommodate the more pronounced tubing presence.

Probably tempting fate here, but still holding pressure and running cool after 5 years.

Peter

[Iceni John]

I know it's not ideal, but why not use flared unions? I hard mounted bulk head fittings on angle aluminum. It worked pretty well for me.

How many evaporators are you installing? (Sounds like 2?)
Could you loop the line instead of doing hard bends? Most of the time, hard 90s are frowned upon in installations.

You probably already know this, but there is a minimum line set length as well as a maximum. 21ft is probably long enough. My condensor is in the middle of my (45') bus and the evaporators are on front/back wall.

I'm also assuming you're using a decent bender. I'm using this one: https://www.amazon.com/gp/product/B089MYQ5SV

They also make insertible mandrels. I think they are made of some sort of plastic. They allow you to free bend the copper without kinking it:   https://www.pioneerminisplit.com/products/lineset-bender-kit

I have only one evaporator (it's just a 12K minisplit) inside about ten feet behind the right front wheel, but because the condenser unit is under the floor directly above the front axle the lines have to take a circuitous route from A to B.   I've now bought another set of insulated 1/4" and 1/2" copper lines because I don't trust the old lines' integrity after over-bending them, so I'll use the old ones to practice with:  as far as I'm concerned they're now just scrap.

That bender kit from Amazon looks OK, certainly better than my bender now, so maybe I'll just get it, even though I already have several tubing cutters and a deburrer.   Can't have too many tools!

The internal mandrels won't work too well for my 21-foot lines!

To make it easier on the next tubes, I plan on separating the two sizes, then cutting off their insulation so I only have to deal with the copper itself.   I can easily (he says optimistically...) reattach the insulation afterwards.   Wish me luck!

Thanks, John   

[Iceni John]

I feel your pain.

It took me a while and I had to work the curves real slow, ruined the first set of tubes and had to get a second, also had to get a better quality flaring tool.

My original plans of some hard bends got changed to much longer sweeping curves, but I eventually got it done.

Maybe long sweeping curves are not possible in your case?

I had to make a few changes to the interior design to accommodate the more pronounced tubing presence.

Probably tempting fate here, but still holding pressure and running cool after 5 years.

Peter

I wish I had only nice sweeping curves in easily-accessible places.   Unfortunately I have four tight 90-degree bends in very inaccessible locations under the floor, plus countless other slight bends along the way.   Maybe I should have installed the A/C first before everything else!

John

[epretot]

Iminisplit) I've now bought another set of insulated 1/4" and 1/2" copper lines because I don't trust the old lines' integrity after over-bending them, so I'll use the old ones to practice with:  as far as I'm concerned they're now just scrap.

The copper is available in both sizes from Grainger.

[Glennman]

I feel your pain.

It took me a while and I had to work the curves real slow, ruined the first set of tubes and had to get a second, also had to get a better quality flaring tool.

My original plans of some hard bends got changed to much longer sweeping curves, but I eventually got it done.

Maybe long sweeping curves are not possible in your case?

I had to make a few changes to the interior design to accommodate the more pronounced tubing presence.

Probably tempting fate here, but still holding pressure and running cool after 5 years.

Peter

Mine are almost just like yours. I installed above the floor where the front wheel well is then up the side and eventually to the destination sign area. Where they go above the floor, that is now behind the couch. Where they go up behind the driver, I installed 2" electrical conduit over them (the gray matches the interior). I ran the conduit through the table saw removing a large portion along one side so that I was able to simply push it over the lines after they were already installed. The Rehabit8 couple on YouTube installed the flexible lines after theirs failed on the road. I guess the original lines sprung a leak eventually. They installed (2) sets in order to get the length they needed. I hope you figure this out!

[Iceni John]

Mine are almost just like yours. I installed above the floor where the front wheel well is then up the side and eventually to the destination sign area. Where they go above the floor, that is now behind the couch. Where they go up behind the driver, I installed 2" electrical conduit over them (the gray matches the interior). I ran the conduit through the table saw removing a large portion along one side so that I was able to simply push it over the lines after they were already installed. The Rehabit8 couple on YouTube installed the flexible lines after theirs failed on the road. I guess the original lines sprung a leak eventually. They installed (2) sets in order to get the length they needed. I hope you figure this out!

My latest idea (I keep changing my mind as I learn about different solutions!) is to use a 16-foot flexible lineset from Parker Davis that should easily get around corners and through gaps that copper line cannot, and add two 6-foot RectorSeal NoKink flexible lines (one 1/4" and one 1/2") to extend it to the 21 feet or so that I need.   I had ordered another copper lineset from Global Industrial two days ago to replace the original one I buggered up, but I'll return it unused and unopened because I don't think it will work any better than the original one.   Another benefit of using flexible lines throughout is that if I ever need to slightly move the indoor or outdoor units for maintenance, the flex lines will give me enough slack to do so easily without risk of overbending copper lines.

I used Electriduct aluminum raceway in the 3" x 2" size to hold the lines coming down from the indoor unit through the floor, but I had to cut and rejoin it twice to create a 5-degree bend and a 2.5-degree bend so it can follow the angles of the window pillar and side wall without any gaps behind it.   Nothing's easy! 

Do you know offhand what flare angle are used for minisplit lines?   I can buy flare unions in either JIC 37 or SAE 45 degrees to join the Parker Davis and RectorSeal sections, but because of the pressures involved with R410a I obviously need to use unions with the correct angle!   My minisplit flaring tool doesn't state which angle it makes.

John

[mqbus767]

Sounds like a good plan. A 410a unit should have SAE 45 flares. Double check your unions are correct too.