After wrecking my 2nd elbow, figured I'd better ask the experts

[GregInCos]

Had some issues with my central air. Eventually figured out the condensation drip line was plugged up. Unfortunately when it was installed they put no easy way in to actually clean it, so I ended up cutting it off all the way up to the "what I thought" was a standard 3/4 inch elbow that came out of the furnace.



So I went to Home Depot and bought a 3/4" elbow took it home and tried to put it on and wrecked it. Went back and bought another one and was more careful but still wrecked it. Tried putting this one back on and it goes in perfectly. Looking at the 2 elbows, it looks like this one is a slightly different size. Here is the exact part from the old elbow.


So what exactly am I looking for? The Home Depot one won't work. Where should I be looking for the correct elbow?

Thanks so much

 

[JG plumbing]

Looks like 3/4"pvc x 1/2" npt. Find a half inch threaded something or other and screw it into the hole to check the size.

 

[JG plumbing]

Also it can be tough to screw plastic into metal. You have to get it lined up softly or you just ruin the threads on thy plastic.

 

[Twowaxhack]

It’s 3/4” iron pipe size threads. If first you don’t succeed, try again.

 

[GregInCos]

Looks like 3/4"pvc x 1/2" npt. Find a half inch threaded something or other and screw it into the hole to check the size.

I'd checked this. it's definitely closer to 3/4 inch than 1/2 inch npt.

 

[GregInCos]

It’s 3/4” iron pipe size threads. If first you don’t succeed, try again.

Sorry for my ignorance, but not sure what that means. Do I need a different type of part that fit the "iron pipe size threads"?

 

[Twowaxhack]

Sorry for my ignorance, but not sure what that means. Do I need a different type of part that fit the "iron pipe size threads"?

You need a 3/4” threaded street 90.......

That’s what you took off, I checked the part number on your old fitting.

 

[Twowaxhack]

Usually that’s plastic threads on the AC unit. Not sure why you’re having issues.

maybe try a different brand pvc fitting.

Be careful and don’t over tighten it and crack your AC drain outlet.

I wouldn’t use Teflon tape, pipe dope only.

 

[GregInCos]

Went and bought a slightly different model, but it does the same thing. Can get it started, but about one turn in, it would strip the thread if I kept going. I can put the old one on perfectly every time. When I hold them side by side, the sizes look different. The Plumbing supply store is open tomorrow. might go tomorrow and see if they have any that look closer. Just confused.

 

[Twowaxhack]

Here’s the exact part number of your old fitting. Order it.....?

https://www.amazon.com/Mueller-410-007-Slip-MPT-Street/dp/B007ICC0JM

 

[JG plumbing]

It's just tough to get started. It's not a part number issue. I've seen people mess with this for long periods of time. You have to hold your tongue right and use the right cuss words.

 

[JG plumbing]

Your getting started crooked. It may feel like it's aligned, but it's crooked.

 

[JG plumbing]

The threads are guiding you and you think your starting good, but it's a lie.

 

[Twowaxhack]

I’ve had pvc adapters from one brand that wouldn’t thread in but another brand would screw right in.

So it is a thing.

 

[JG plumbing]

Your interpretation.

My interpretation is npt would fit npt. The slightest difference in the manufacturers die would make one harder than another to get screwed in, but it does work. Npt is npt, unless there is a real malfunction or oddity on a bad batch.

 

[Twowaxhack]

Your interpretation.

My interpretation is npt would fit npt. The slightest difference in the manufacturers die would make one harder than another to get screwed in, but it does work. Npt is npt, unless there is a real malfunction or oddity on a bad batch.

there’s no interpretation about it. One manufacturer can thread in and another won’t.
I didn’t imagine it.

The fitting has plastic before the threads start......some fittings this plastic is longer before the threads start.

 

[JG plumbing]

Next time step aside I'll do it, lol.

 

[JG plumbing]

One time me and another guy were putting in a Bradley sink. I tried screwing a plastic female adapter into the outlet on the bottom of the sink for about 30 min, cussing the whole time, then the other guy tried for about 30 min. Then we went and did something else for a while to clear our frustration. We came back, I messed with it for about 10 min and it finally hit the right threads and it screwed right in.

I would agree with you if I didn't have two more stories like this.

 

[JG plumbing]

I doubt this guy has a 3/4" npt die otherwise that could help.

 

[GregInCos]

I doubt this guy has a 3/4" npt die otherwise that could help.

That would be a correct assumption