PVC for Mini Split Drain?

[SVibs]

I’m doing the electrical rough-in and other prep while I wait for my mini split to arrive. My HOA doesn’t allow line set covers running on outside walls (yeah, I know) so I’ll have a 5’ horizontal run of covered line set inside the garage before I get inside the required stud bay, run down the wall and out to the condenser. I’m not thrilled about running the corrugated condensate drain line horizontally and even less thrilled about running it inside the wall.

The line set will be exiting the evaporator on the right side. I have the stud bay to the left of where the evaporator will be mounted partially opened up so I can run 10/2 to the panel. I’m thinking of running ¾” PVC inside this stud bay but I’m not sure about the drain hook up. From the info I’ve been able to find, P-traps or running bend traps seem to be a no-no. Do I simply insert a short length of the drain tubing in the PVC pipe. Or do I use a mini split drain adapter like this one?

 

[pcmeiners]

Used something close to the drain adapter linked. You need a trap or air will move in the drain line, causing condensation. possible 4 or more legged live things traveling up line. I used both 3/4" PVC and 5/8" vinyl clear tubing for drain lines. As to the drain. I do not hook into the sewer or septic, drain outside or drill the slab and drain to the gravel.

 

[dcg9381]

As the regular ductless lines don't have traps, I know I didn't fiddle with one... Just ran 3/4" PVC inside the walls, both 24K units drain into a single 3/4 PVC line.

 

[Jackfre]

Get a 1/2” barbed plastic fitting x mpt adapter and hose clamp it to the flexible drain line. Put the mpt into a 1/2 fptx 3/4 slip. Make sure you do not trap this line. You are correct on “in the wall” being a pitn.

 

[SVibs]

Thanks guys.

 

[jjrbus]

I did not know about the adaptors and had a buddy turn down the end of a 3/4" PVC pipe on his lathe. A short piece of 3/4 and a coupling.

 

[branimal]

When running 3/4" PVC in the walls for mini-split condensate, does anyone put a cleanout along the run? Is it worth it?

I'm thinking a wye fitting with a threaded cap on the inlet. The idea being you could blow air down the pvc pipe.

I'm going to have access panels in locations where I brazed the lineset. Figured this would be an ideal place for a cleanout.

 

[rlitman]

Is this trap going to be in a wall space that can freeze? If so, I'd either run it in something that isn't going to burst when it does freeze, or figure out a way to both seasonally blow it out, and keep out creepy crawlies.

 

[branimal]

Is this trap going to be in a wall space that can freeze? If so, I'd either run it in something that isn't going to burst when it does freeze, or figure out a way to both seasonally blow it out, and keep out creepy crawlies.

It's not a trap, just a wye. Plan is to eventually run the pipe outside with a bug screen on it. It will not be in a wall that freeze until it reaches it's final exit point.

Now that I think about it this might not be a great idea. Some of that compressed air might rush up to the indoor unit and create a mess.

 

[dcg9381]

When running 3/4" PVC in the walls for mini-split condensate, does anyone put a cleanout along the run? Is it worth it?

I have not had a problem with it, it's been 3 years or so. I used the condensate water, plants love it. I have not cleaned the ductless lines. But ours are not in use for more than a few days at a time.

I'm thinking a wye fitting with a threaded cap on the inlet. The idea being you could blow air down the pvc pipe.
I'm going to have access panels in locations where I brazed the lineset. Figured this would be an ideal place for a cleanout.

Our traditional HVAC drains are PVC and they do need to be cleaned in our climate. Usually they are just an open wye fitting and you put a cup of bleach down the drain 1-2x per year. If you wait to long (like I have many times) you'll end up with a pain in the ***.

To do what you want to do, you need a valve that closes off upstream to the ductless, then a add a pressure fitting... But this is if you've got a line that is so clogged that you need to use forced air to clear it. Worst case, I've attached a shop vac to the outside end and sucked while adding bleach (traditional AC).

 

[branimal]

Usually they are just an open wye fitting and you put a cup of bleach down the drain 1-2x per year. If you wait to long (like I have many times) you'll end up with a pain in the ***.

I've attached a shop vac to the outside end and sucked while adding bleach (traditional AC).

Interesting.... what is in the pvc lines that you need to run bleach down it? Whats coming up in the shop vac? Forgive my cluelessness.

 

[dcg9381]

Interesting.... what is in the pvc lines that you need to run bleach down it? Whats coming up in the shop vac? Forgive my cluelessness.

Apparently it's colony forming bacteria:



In TX, AC is running very very often, maybe 20+ hours a day and what happens is you get some sort of "slime" build up. If you let it go too long, the line will plug. Just hope your HVAC tech installed the pan right (no leaks) or you've got a good float system...

It's likely not happening on our ductless lines as we don't use the HVAC in the shop full time and those lines can dry out.

Happens pretty much to all the homes here. They make additives (tablets) for the pans and lines to keep the slime at bay....

 

[Kaizen]

Get a 1/2” barbed plastic fitting x mpt adapter and hose clamp it to the flexible drain line. Put the mpt into a 1/2 fptx 3/4 slip. Make sure you do not trap this line. You are correct on “in the wall” being a pitn.

This. I had to run mine for about ten feet and used a blue sprinkler piece from home depot like the one below. it kind of screws into the line from the indoor unit and i put a female fitting on the pvc. I ran my 3 line sets so i could drop each into the pvc that runs on the outside of the house. NO NO NO drain trap. put a screen over the end of the pvc to keep bugs out. I gaurentee you'll need to clean out gunk from these lines and if the old vacuum trick doesnt work you'll want to be able to run a snake.
I was wondering about it freezing but really don't run the minisplit below 40 as its not any cheaper then oil. I did run it below freezing for a few days and did not have a problem. I have a 50 gallon rain barrel at the end that i collect the water for the garden. On those humid days its like a faucet

Apollo 3/4 in. Barb Insert Blue Twister Polypropylene x MPT Adapter Fitting ABTMA34 - The Home Depot

This innovative and patented Twist-In polypropylene 3/4 in. male pipe thread adapter can be used to connect polyethylene pipe to a male threaded connection originating from a valve or alternative type

www.homedepot.com

 

[dcg9381]

I was wondering about it freezing but really don't run the minisplit below 40 as its not any cheaper then oil. I did run it below freezing for a few days and did not have a problem.

In heating mode, I don't know why you'd be getting condensation from the inside unit. You're basically running it backwards and it can condensate (or freeze) on the outside unit in heat mode - which is why most of these have a defrost deal.

 

[Kaizen]

In heating mode, I don't know why you'd be getting condensation from the inside unit. You're basically running it backwards and it can condensate (or freeze) on the outside unit in heat mode - which is why most of these have a defrost deal.

yea mine does but the indoor units do some voodoo stuff as well. Makes a bunch of sounds. Wasnt sure if there was some runoff as the indoor moisture is higher then outdoors

 

[dcg9381]

yea mine does but the indoor units do some voodoo stuff as well. Makes a bunch of sounds. Wasnt sure if there was some runoff as the indoor moisture is higher then outdoors

Come to think of it, when the unit defrosts, it might be possible to generate some condensate inside... I've just never noticed much (if any) run off in heating mode. I don't know frequently they defrost - probably depends on a number of things.

Moisture condenses when cooled, so as long as your indoor coils are warmer than than ambient, you won't get condensation within the indoor unit.

 

[branimal]

Apparently it's colony forming bacteria:

Well you've convinced me to add a wye cleanout which i can pour bleach down. My PVC pipe serves 3 mini-split units which are all below one another.

I'll connect the mini-splits flimsy condensate tube to a 3/4" PVC Schedule 40 Insert x Socket Adapter.

From there it's just 3/4" pvc pipe and fittings all the way to the exit on the first floor. I can glue a threaded male pvc adapter onto a wye on the third floor. Screw a cap onto the male adapter for access. All of that will sit behind an access panel.

Gravity should take care of the rest.

 

[PoorUB]

I’m doing the electrical rough-in and other prep while I wait for my mini split to arrive. My HOA doesn’t allow line set covers running on outside walls (yeah, I know) so I’ll have a 5’ horizontal run of covered line set inside the garage before I get inside the required stud bay, run down the wall and out to the condenser. I’m not thrilled about running the corrugated condensate drain line horizontally and even less thrilled about running it inside the wall.

The line set will be exiting the evaporator on the right side. I have the stud bay to the left of where the evaporator will be mounted partially opened up so I can run 10/2 to the panel. I’m thinking of running ¾” PVC inside this stud bay but I’m not sure about the drain hook up. From the info I’ve been able to find, P-traps or running bend traps seem to be a no-no. Do I simply insert a short length of the drain tubing in the PVC pipe. Or do I use a mini split drain adapter like this one?

You need to run it in PVC! If you run horizontally with any flexible tubing, it sags and creates traps that eventually clog up from bacteria and other nastiness. Also, slope the horizontal run so it drains. Use the drain adapter and connect it properly so you can blow it out if you need too. A trap might help, but put the trap outside where you can get to it, and don't glue it on so you can just pull it off and clean it.