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  1. #40
    Join Date
    Oct 2004
    Posts
    3,400
    Originally posted by ct2
    ...so I will simply say that it is recomended that the coil also be changed due to the higher pressures associated with 410a
    ct2, why aren't you in class?
    You didn't graduate already did you?

    Did you see the "correct me if I am wrong", part?
    I'm always willing to learn.

    Have you cut one open yet?

    I've got a few 410a coil lab samples from various manufacturers, and they are woefully thin, in search of the mighty SEER/COP.
    They are encased in plastic, so hard to actually measure thickness.
    I have a few new coils & systems in my labs that I could sacrifice in the name of education.
    That might be a good project for next week.
    After I cut one up, I'll send you a piece of it, if you want it.
    I usually give my classes a chance to ruin new equipment before dissection, but I am willing to shortcut the process.

    The question was about the connecting tubing, not the coil.
    The lineset will be MUCH thicker than the coil, old or new, therefore not the weak link. The header on the coil is thicker, too. The thinnest part of the coil is the part that is covered with fins, plus the return bends, usually at the back of an A-coil.

    It has ALWAYS been recommended to change the indoor coil, so why should R-410a be any different?

    As usual, correct me if I am wrong.
    Heap it on, my shoulders are broad...

  2. #41
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    not being on the front line, what is the highest pressure to be expected?

  3. #42
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Originally posted by stef

    quote:
    --------------------------------------------------------------------------------
    Originally posted by stef
    High humidity out side has nothing to do with the service.
    --------------------------------------------------------------------------------


    We just had some rain here in the DFW area and water squishes up out of the ground when you walk on it. I wouldn't open up a R-410a system today.
    __________________________________________________ __

    If you are concern about it is fine.

    But are we pouring freon in the bucket then scope it in the system??????

    Even with 0 degrees outside or raining outside. We can still weight the exact amount of freon in the system, which is by the way the best method of charging the system. As long as your gauge is in the dry location.

    Have fun
    The outdoor temperature isn't the problem, its the water falling out of the sky, or the near 100% RH at ground level that would make me rescedule a call where I was going to have to open up an R-410a system for repair. I don't even do any kind of work on the refrigerant side of r-22 systems when it is very wet, I'm sure has heck not gona do it on a R-410a system...
    If more government is the answer, then it's a really stupid question.

  4. #43
    Join Date
    Feb 2005
    Posts
    21
    Well, a tech came out today and spent a couple of hours checking for the leak. His detector couldn't find any presense of freon in the air handler, or the outside unit. He could get the probe a little into the header of the wall where the line went in, but still couldn't detect anything.

    So, monday they are supposed to call me with a cost to replace the line sets and to schedule an appointment. Glad the temps aren't too cold (or hot).

  5. #44
    Join Date
    Oct 2004
    Posts
    3,400
    Originally posted by stonecipher
    Well, a tech came out today and spent a couple of hours checking for the leak. His detector couldn't find any presense of freon in the air handler, or the outside unit. He could get the probe a little into the header of the wall where the line went in, but still couldn't detect anything.

    So, monday they are supposed to call me with a cost to replace the line sets and to schedule an appointment. Glad the temps aren't too cold (or hot).
    He couldn't find the leak, so he blames it on the hidden tubing.

    If it were me, I would have isolated (actually cut the tubing, both ends), and performed a standing pressure test on each line.
    Or use a micron gage.
    Or both.
    (I probably would have, before brazing them into the new coils, but that's a different story...)

    I hate parts changers.

    But that's just me.

    I hope it doesn't have a little leak on the bottom of the accumulator, or somewhere else, not so ordinary.

  6. #45
    Join Date
    Feb 2005
    Location
    Alabama
    Posts
    534
    Did the Tech check for a possible leak somewhere in the lineset? how long is the lineset and is it in a soil pipe, under the house, or in the wall. I had to replace a lineset recently due to a leak in the wall. Ran the new lineset down the outside of the house and covered it with a section of down spout material. Looked pretty good when I was done and Mr. Homeowner was happy too.
    "If you can't fix it, don't break it."

  7. #46
    Join Date
    Feb 2005
    Posts
    21
    Originally posted by duct dr
    Did the Tech check for a possible leak somewhere in the lineset? how long is the lineset and is it in a soil pipe, under the house, or in the wall. I had to replace a lineset recently due to a leak in the wall. Ran the new lineset down the outside of the house and covered it with a section of down spout material. Looked pretty good when I was done and Mr. Homeowner was happy too.
    Hey ductdr!

    The line runs about 15 feet over to the outside wall from the air handler. The line in the wall is original, then the first installer replaced the line from brick wall to the outside unit.

    He pulled back the insulation from the lines upstairs and checked both ends. He put the little sniffer probe (I have no idea what to call it, freon detector) into the header of the wall also. He stated that usually it would go off if there was freon buildup in the wall. The brick mortar is too tight to check from the bottom. He spent about two hours going over every bend and connection on both units.

    We will probably do the same thing next week, as far as running the lines outside the wall. I'm assuming you used some kind of closed cell foam insulation?

    bwal2 -

    He didn't do a leak down test, although at this point I don't mind just replacing the lineset. The units are under ext. warranty, and they will be liable for the new lines. If leaks do occur 6 months later, there aren't any more unknowns or excuses. It's all new and someone is responsible for each component. I've already paid enough overage on my elec. bills in the last 2 months to cover the line set replacement.

  8. #47
    Join Date
    Feb 2005
    Location
    Alabama
    Posts
    534
    Well lets see (scratching brain). It is possible that a small leak is just behind the brick where it goes up. I've seen that before and detecting such a leak can be hard if you can't get the sniffer tube in there. And depending on how sensitive the sniffer is it may or may not pick up the leak on the other end of the lineset. Running the lineset down the outside of the wall is easy, punch a hole through the soffet, use a section of gutter downspout material to cover it up, strap it to the wall, and make sure the hole in the soffet is sealed up good. make sure though they replace the entire lineset, not just what's IN the wall. We had a strange problem here a couple years ago at an apartment complex where units were losing freon, yet NO leaks were found. After doing some snooping around we found out that kids (teens) were taking the caps off the service valves, attaching a hose the the fitting and actually snorting the freon. Strange but true.
    "If you can't fix it, don't break it."

  9. #48
    Join Date
    Oct 2001
    Posts
    6,071
    OK, I have read along here for a while and ran across something that is troubling me.

    I have been off my tools for about 5 years now, but when I hung up my pouch, 410A was just getting started good. Carrier taught us that you had (and I mean HAD!) to replace the copper, coil and any other component that contained mineral oil before hooking up the 410A stuff, due to POE oil being a dehydrated acid.

    While working at my last job and putting in my hours in the model shop, we spent more time cleaning up systems to convert to 410A than we did designing them.

    And now, while I am working with POE oils every day, the dehydrated acid part is proving to be a major problem for my project.

    So, has something changed in the field literature so that it is OK to connect old, mineral oil bearing parts to 410A parts?
    Hindsight is NOT a plan!

  10. #49
    Join Date
    Feb 2005
    Location
    Alabama
    Posts
    534
    Oh my god, Bama I didn't see that till now. I feel like an idiot. 4TWX is R410a. There's the problem right there. The remaining R22 oil mixed with the 410a and destroyed the compressor. Solution......Change out the lineset (all of it) and replace the compressor. The HVAC company should catch the bill on that one. I have been told by a Trane Rep that you can use existing copper IF, you purge the copper with nitrogen, and pull a vacuum of at least 400 microns for at least an hour. That process should be repeated 3 times. And that may or may not remove all the old oil. Then, there's the problem of matching copper size, most 410a systems use different size copper. Ex., a 3 1/2 ton R22 system uses 7/8, and 3/8 while a 3 1/2 ton 410a system calls for 3/4 and 3/8, sometimes 5/16 on the liquid line. Thanks again Bama for catching that.
    "If you can't fix it, don't break it."

  11. #50
    Join Date
    Feb 2005
    Posts
    21
    Okay, guys, you're not making my day here. So, do I wait until the compressor fails in the future, and then go after the first installer, or do I go to the local Trane office and try to get something done about it now?

    I'd bet the first installer will say he did whatever he needed to do for a correct install, and try to dodge it. Since he was a Trane Comfort Specialist, I would assume the install would be covered by Trane in the Ext. Warranty.

    I hate this crap <sigh>

  12. #51
    Join Date
    Feb 2005
    Location
    Alabama
    Posts
    534
    Have it taken care of NOW stone, and I'm sorry for misreading the first post. I didnt see where you have a 410a system, and I should have. Call Trane as soon as you can and get the line set and compressor changed out.
    "If you can't fix it, don't break it."

  13. #52
    Join Date
    Oct 2001
    Posts
    6,071
    Well, I sure did not mean to ruin your day. Sorry.

    If the POE oil in your system has gone to acid, there are tests to determine. If those tests come back positive, Trane will foot the boot for equipment repair or replacement, even though they are not directly at fault.

    The contractor, on the other hand, may not do the right thing so easily.

    Good luck to you and be sure to let us know how it turns out.
    Hindsight is NOT a plan!

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