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  1. #1
    Join Date
    Feb 2011
    Location
    Atlanta, Georgia
    Posts
    21

    4 way reversing valve question

    I was just reading in my school book that when installing a 4 way valve it should not be subject to excessive heat.

    I was presented a question stating when brazing a 4 way reversing valve heat absorbing paste should be placed around the body of the valve to minimize the chance of internal damage to the valve.

    Book doesnt clearly indicate if this is a fact or bull poo. A little help would be great.

  2. #2
    Join Date
    Dec 2007
    Location
    houston, texas
    Posts
    3,787
    A lot of guys use the paste, never have myself. They make a fork shaped tool for the torch that will allow you to heat all three pipes at one time to minimize the heating time needed to remove the valve.

    You can also use tubing cutters to remove the old one and then just fit the new valve in place. If you unsweat the valve be ready for an unpleasant experience with the phosgene gas you'll encounter.
    I'm not tolerating Political Correctness anymore, from now on it's tell it like it is.

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  3. #3
    Join Date
    Feb 2011
    Location
    Atlanta, Georgia
    Posts
    21
    I am guessing according to your statement that this can be a true statement. If the valve is heated with no protection there is a chance that the internal components can be damaged.

  4. #4
    Join Date
    Jul 2001
    Location
    Southern NJ
    Posts
    1,241
    You should do something to protect the valve:

    Use the paste you're talking about
    wrap the valve with a rag
    use a lot of heat so you can braze really fast.

    Any of the above works, a combination of 2 is even better.
    Ryan
    Maintenance Guy
    -----------------
    naysayer, skeptic, conspiracy theorist

  5. #5
    Join Date
    Nov 2010
    Location
    Nebrasky
    Posts
    35
    alot of guys will use 45% rod instead of 15 so they don't need as much heat, it's more expensive though.

  6. #6
    Join Date
    Dec 2010
    Location
    Palm Beach,Fl.
    Posts
    990
    There are teflon seals and seats inside that can be damaged if they get too hot.

    I usually unsweat the discharge line and cut the other 3 at the easiest spot where I can add couplings and remove the whole assembly and mark the positions of the pipes before unsweating them from the valve itself. If i cant get a tubing cutter in there I have no problem taking them off with a sawzall, cut flush with the joints and use reducer couplings to go into the new valve.

    Sweat the stubs into the new valve one at a time with a wet rag to keep it cool and then reconnect the piping with couplings.

  7. #7
    Join Date
    Mar 2011
    Location
    Manchester NH
    Posts
    208
    Quote Originally Posted by SoFlaDave View Post
    There are teflon seals and seats inside that can be damaged if they get too hot.

    I usually unsweat the discharge line and cut the other 3 at the easiest spot where I can add couplings and remove the whole assembly and mark the positions of the pipes before unsweating them from the valve itself. If i cant get a tubing cutter in there I have no problem taking them off with a sawzall, cut flush with the joints and use reducer couplings to go into the new valve.

    Sweat the stubs into the new valve one at a time with a wet rag to keep it cool and then reconnect the piping with couplings.
    SoFladave your not worried about any metal shavings getting inside the lines by using a sawzall. Just wondering??

  8. #8
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    4,380
    A while back a member posted pictures of how to change the valve using stubs and such. I think he submerged the valve in water (I know it doesn't sound logical) and brazed his stubs on. He might of used wet rags. Might be worth running a search.

  9. #9
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    Quote Originally Posted by HVAC-matt View Post
    SoFladave your not worried about any metal shavings getting inside the lines by using a sawzall. Just wondering??
    The discharge line is on the bottom, unsweat that and cap the line going to the compressor. Cut the other three, the shavings will fall into the valve your taking out, its already bad whats it gonna hurt.
    Karst means cave. So, I search for caves.

  10. #10
    Join Date
    Mar 2011
    Location
    Manchester NH
    Posts
    208
    Quote Originally Posted by karsthuntr View Post
    The discharge line is on the bottom, unsweat that and cap the line going to the compressor. Cut the other three, the shavings will fall into the valve your taking out, its already bad whats it gonna hurt.
    Ok I was just wondering bc in school they had told us never to use a sawzall or hack saw. Makes sense thanks.

  11. #11
    Join Date
    Apr 2005
    Location
    where the beer flows like wine
    Posts
    2,871
    Quote Originally Posted by Texas-Tech View Post

    If you unsweat the valve be ready for an unpleasant experience with the phosgene gas you'll encounter.
    I thought we were beyond that point!!brazing/un-brazing etc does not generates any phosgene gas, another old wives tale.

  12. #12
    Join Date
    Dec 2010
    Location
    Palm Beach,Fl.
    Posts
    990
    Whatever the compound thats produced when refrigerant passes through a flame actually is, its extremely unpleasant at best.

  13. #13
    Join Date
    Dec 2010
    Location
    Palm Beach,Fl.
    Posts
    990
    Quote Originally Posted by HVAC-matt View Post
    Ok I was just wondering bc in school they had told us never to use a sawzall or hack saw. Makes sense thanks.
    Basically, if it can be done with tubing cutters, by all means thats the best way. Sometimes you gotta do what you gotta do though.

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