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  1. #1
    Join Date
    Jul 2014
    Location
    St. Louis
    Posts
    18

    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

  2. #2
    Join Date
    Mar 2014
    Posts
    37
    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.

  3. #3
    Join Date
    Jan 2013
    Location
    d'Iberville, Miss.
    Posts
    51
    X2

  4. #4
    Join Date
    Jul 2013
    Location
    Richmond, VA
    Posts
    436
    Use nitrogen
    I'm terrible.

  5. #5
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    148
    Have you assisted in changing parts like these before?

  6. #6
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,441
    Quote Originally Posted by Joz900 View Post
    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
    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.

  7. #7
    Join Date
    May 2011
    Location
    Western, KY
    Posts
    2,946

    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.

  8. #8
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,433
    Quote Originally Posted by pecmsg View Post
    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.

    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.

  9. #9
    Join Date
    May 2011
    Location
    Western, KY
    Posts
    2,946
    Quote Originally Posted by jpsmith1cm View Post
    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!

    It takes away so much of the "magic", you can "see" what's happening and why.

  10. #10
    Join Date
    Nov 2007
    Location
    Mississippi
    Posts
    1,307
    Set acetylene regulator to 7 and oxygen regulator to 18. Even some seasoned techs forget this.

  11. #11
    Join Date
    Nov 2011
    Location
    St. Louis
    Posts
    3,235
    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 pray it works, pray to God it works."

    ---Nick's Handyman

    https://www.youtube.com/watch?v=rySKAuk4XiM

  12. #12
    Join Date
    Nov 2011
    Location
    St. Louis
    Posts
    3,235
    Quote Originally Posted by socotech View Post
    Set acetylene regulator to 7 and oxygen regulator to 18. Even some seasoned techs forget this.
    And some disagreements as well...as I was taught 7-11 and use the nozzles to dial in
    "...and pray it works, pray to God it works."

    ---Nick's Handyman

    https://www.youtube.com/watch?v=rySKAuk4XiM

  13. #13
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,433
    Quote Originally Posted by hurtinhvac View Post
    And some disagreements as well...as I was taught 7-11 and use the nozzles to dial in

    Yep. Disagree even with this.

    The pressure on the regulators are determined by tip size.

    There is no hard and fast rule.

    http://victortechnologies.com/IM_Upl..._0056-0138.pdf

    Scroll down to page 7-17

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