tips for swapping coils/compressors
had my 6 month review today, and they decided to give me a more diverse work load other than the normal PM's and no calls.
work load will now entail installing TXV's, evaporator coils, and compressors. You guys have any advice, details I should look out for?
I usually try to let the guys know weather it's a 80 or 90% furnace just so they can bring couplings and stuff with them! but other than that they usually say everything went "fine".
Any advice would be useful
Remove the bulb when you sweat the coil in and sand all joints to be brazed....even new copper and the solder will flow right in the joint.
Have you assisted in changing parts like these before?
Every part / component has some type of paper work in the box. Take it home and read it sometime, you’d be surprised what’s in there.
Originally Posted by Joz900
tips for swapping coils/compressors
Cool man, keep learning and getting better!
How's your brazing? See if they'll let you take some scrap copper home and practice, practice, practice. You need to understand how to choose your torch and tip for the application. A number 11 b tank tip is not what you want when brazing in a TXV. I usually go for the oxy/acy and a #1, unless its a bigger line and I'll go with #2.
Know that if you flow nitro it needs a place to flow out of/release or it will blow your rod out and leave a pin hole. An example would be that when swapping an evap coil you would purge the nitro through the high side tap with low side schrader removed. A nitrogen flow meter works great for this, you only want a trickle but you should purge the line first to make sure its all nitro.
Keep a bucket of wet rags handy and put the wet rags on anything too sensitive close by, you can also use them to speed up cooling the joints when you're done. Say there's something behind where your brazing that you don't want to set on fire or melt, put a wet rag over it.
I prefer to cut my coils out because sweating them out can often lead to a fireball shooting out at you, not fun right to the face in an attic while standing on joists.
Clean every joint before brazing, sand cloth is your friend.
I use 45% blue rod on the compressors stubs to avoid the 15% not taking when the stub is not covered in copper well and you end up dealing more with the steel.
Always do a nitrogen pressure test. I usually test at 150 or 175psi for ten minutes.
Get a good vacuum pump, BluVac micron gauge(my preference), vacuum hoses, and valve core removal tools(I like appions). By removing cores you get a faster vacuum and the appion VCRT's allow you to check the microns of just the system, I've had great results. Use nylog on your connections and also use nylog on txv's or pistons that bolt on instead of sweat.
Read all instructions, when possible take the instructions home the night before you have the repair so you can be prepared the next day. I still do this on things I'm unfamiliar with.
Ask for advice from fellow techs but always be skeptical, don't assume they are right. Look for literature on txv's and compressors,etc from the manufactures, read carefully but know that its not always 100% applicable in 100% of applications. You have to learn how to filter all the information and save the good stuff, get rid of the bad.
Don't get in a rush, think things through. Inexperienced and in a rush = mess ups, cutting corners and possible injury.
Originally Posted by pecmsg
I'll go this one better.
If there is no warranty on the part and the homeowner or equipment owner doesn't want it to verify that you're honest, take THAT home.
Sit down on a Saturday afternoon and tear those TEVs apart. Study them. Learn how they work. Learn WHY they fail.
Cut a compressor or two apart. See how they are built and how they work. See if you can determine why it failed.
Before you cut those evaporator coils up for scrap, pressurize them and pinpoint that leak.
All of this is good practice.
Oh yes, that helped/helps me a ton!
Originally Posted by jpsmith1cm
It takes away so much of the "magic", you can "see" what's happening and why.
Set acetylene regulator to 7 and oxygen regulator to 18. Even some seasoned techs forget this.
I'd invite you at this point to apply for pro status and join us in the locked sections. There you can ask detailed questions and find many techs who will patiently walk you through any procedure. And a few haters as well - but their mothers didn't like them either.
And some disagreements as well...as I was taught 7-11 and use the nozzles to dial in
Originally Posted by socotech
Originally Posted by hurtinhvac
Yep. Disagree even with this.
The pressure on the regulators are determined by tip size.
There is no hard and fast rule.
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