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View Full Version : What causes a bent Schrader?



Rustytool
06-26-2016, 09:19 PM
Little back story
Friday went to a no ac call, unit blowing warm air.
I go to put my gauges on, hear hissing as soon as I take the cap off. Try to tighten the Schrader, no luck still hisses.I replace it.
Find its bent right after the threads causing it to not seat properly.
I put new one in, do a quick leak check, gas it up and leave.

Didn't really give it a second thought until right now sitting on my couch.

What causes a bent Schrader? It was bent maybe 20-30 degrees.
My thinking is no way refrigerant could do it.(the pressure)
Even if you cross threaded your gauges putting them on, it wouldn't tighten enough before you caught it right?

Maybe it was bent in the factory and the installer didn't pull it while tieing in the condenser?

Anyone ever come across this before?
Thanks

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Core_d
06-26-2016, 09:45 PM
yea ive seen it once same deal and I figured aonther tech did it. although I'm not sure how.

AJS HVAC
06-27-2016, 12:47 AM
Maybe it got overheated because it wasn't pulled when the lines were braised

TechmanTerry
06-27-2016, 02:13 AM
Was that on the CU service valve or a add on Schrader T ?

Rustytool
06-27-2016, 11:21 AM
Was on the regular condenser service valve

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DuctLife7926
06-27-2016, 04:50 PM
It was from poor installation. The tech did not use a wet rag and cool gel and even worse did not remove the Schrader while brazing

lkapigian
06-27-2016, 04:57 PM
Basically you're doing work on the material by applying stress, which means you have added enough energy to change the structure of the molecules temporarily (elastic deformation), or permanently (plastic deformation).

A popular misconception is that all materials that bend are "weak" and those that don't are "strong." In reality, many materials that undergo large elastic and plastic deformations, such as steel, are able to absorb stresses that would cause brittle materials, such as glass, with minimal plastic deformation ranges, to break.

slickgoat05
06-27-2016, 06:34 PM
I've seen a green tech screw his gauges to hard onto the port causing the needle part to bend and get stuck and start leaking..has nothing to do with over heating in my opinion.

fozziee2
06-27-2016, 07:59 PM
My helper filled a system up with nitro for a pressure test. When he pulled the gauges off, the Schrader was leaking. Probably only needed a quick poke to re-seat, maybe it was bad, I don't know. Cause he grabbed his Schrader till and tightened it down till the shoulders broke off the Schrader IN THE SERVICE VALVE!

Good times.

Lidecharr
06-27-2016, 08:25 PM
How does that get fixed?

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slickgoat05
06-27-2016, 09:03 PM
You can buy a tool that allows you to change a Schrader under pressure..I carry 1 on my van.

DuctLife7926
06-27-2016, 09:19 PM
I did not see this Schrader as I suspected earlier heat bent the thin metal pin of the Schrader. It could maybe have also have been a dishonest tech / installer who bent it on purpose. I'd likely be able to tell if there was an image.

If a Schrader is leaking the best tool is the valve core removal tool.

If the Schrader is leaking when you first pull the cap, put the cap back on while you grab a new valve and valve tool.

I usually listen carefully as I loosen any valve cap, you might not notice the smallest of leaks while the cap is off but initially there will be enough pressure when you break the seal.

I have seen a Schrader freeze open when liquid charging R-22.

I remove Schrader's while brazing and flow nitro at the smallest levels to not pressurize the lines. I then reinstall the Schrader's and nitrogen test. I then pull my gauges again to set up how I set up my micron gauge, gauges, valves, and pump. When I do this it gives me a chance to test the Schrader's while there only pressurized under nitrogen. I then remove nitro and go to evac.
For me it is not an extra step because I want my micron gauge set up first in line off of the service valves and then the gauges and finally the pump. I also will not pressurize nitro with the micron gauge on, to set it up like this in the previous step.

I was once paired with an apprentice at this company he was about to graduate to a tech and he insisted he wanted to do the brazing. He left the Schrader's out from brazing, cracked the service valves, started and charged the unit, All is complete and he goes to pull the gauges off. He managed to completely remove a hose without realizing it was missing thinking that was the pressure from the hose. (no low loss this long ago). He then managed to get the hose back on in a panic. I heard all this refrigerant hissing and was omw around the corner. He tells me he left the Schrader out. I told him we were going to evac the whole system down, re- vac and then charge since the gauges where back on the unit. Which is what I should have forced us to do. He was adamant that it would take so long the office would know of the error. He pretty much begged me to let him use the valve core tool, on the fly, since he had just done so with the hose on and off. I should have not agreed. He managed to do it, but the office found out anyway because I had to take him to ER for refrigerant burns.
Since then I have been overly cautious of schraders, refrigerant burns, and most important of all allowing someone who I did not fully trust in their abilities handle anything other than picking it up and putting it down and gopher this and gopher that to the truck.
I never forget.

fozziee2
06-28-2016, 04:30 AM
[QUOTE=Lidecharr;23053261]How does that get fixed?

It wasn't a very elegant solution. I basically had to destroy the valve further. I picked at it with a tstat screwdriver and other assorted small pointy things till it broke the pin off. Then I was able to get a small screw driver inside the body off the Schrader with just enough bite to back it out. Then blew a ton of nitro through to blow out any bits.

hogdog1
07-01-2016, 09:47 AM
I wonder what the neighbor kids look like? Klien makes a hvac screw driver with a fitting to remove broken cores.

Core_d
07-01-2016, 03:23 PM
Show us please!!!

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Rustytool
07-01-2016, 10:22 PM
Is that the tip that looks like a cone? Have that on my Klein screwdriver but couldn't figure out what it was for

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heatingelement
07-01-2016, 11:58 PM
Cone shape with thread like looking lines in it. Basically an EZ out for the schrader. Used them all the time back in the day when I did tires.

AJS HVAC
07-03-2016, 12:08 PM
Is that the tip that looks like a cone? Have that on my Klein screwdriver but couldn't figure out what it was for

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That is an electrician model you have. You use it to fix stripped threads in receptical boxes and junctions etc

Core_d
07-03-2016, 01:07 PM
Oh the little cone with left ccw threads.

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rsmith46
07-03-2016, 05:15 PM
What causes a bent Schrader?

I do!

Off to eat some Kansas City BQ..

FilthyCoilz
07-03-2016, 11:11 PM
Get the Appion Valve Core Removal Tool p/n: MGAVCT. I keep two in my bag, mainly for quick vacuum/recharge. To my knowledge, it's the only one vacuum rated(down to 20 microns). Also, the VC extractor tool works like a dream.

As for the bent core, I would guess that whatever was plugged into that port last had a bent depressor or one that wasnt seated correctly and most likely over-tightened to boot. my 2 pennies...

AJS HVAC
07-03-2016, 11:50 PM
I hate when guys use channel locks on caps. All it does is smash the o ring