Page 2 of 3 FirstFirst 123 LastLast
Results 14 to 26 of 31
  1. #14
    Join Date
    Nov 2009
    Location
    Richmond, working under tarps
    Posts
    495
    I get paid by the hour, its up to you.

  2. #15
    Join Date
    Mar 2008
    Posts
    257
    Quote Originally Posted by craig1 View Post
    I have some Tyler systems that are in need of filter/dryer changes. The problem is the piping is arranged like this:

    king valve>dryer>sight glass>service valve>solinoid valve.


    The problem is that once I close both valves to isolate the filter, I have no access to the system. If I use the service valve for access, I will be pulling a vacuum backwards against the solinoid valve. will a solinod valve prevent reverse flow? I wouldn't think so, but maybe I'm wrong.
    LLS are dependent upon upstream pressure, Pump system down, close suction sevice valve and proceed. We install aprox 400 conventional systems per year, we make it standard to install schreder on both sides of LLS for proper vaccume.

  3. #16
    Join Date
    Mar 2005
    Posts
    664
    if you front seat both valves after pump down, that section wil be isolated with ports on valves to evacuate,im sure this is the reason for th 2nd valve, unless i a missing smeting? stan
    Keep it simple to keep it cool!

  4. #17
    Join Date
    Feb 2008
    Location
    California
    Posts
    2,066
    I too do not understand the problem, this is common.

    Pump it down at the King valve and replace the driers.

    Hook up pump and evacuate...you are NOT looking for a micron level vacuum in this situation. Just a good enough one .

    If you are looking for micron levels...you will be there all day. The inner walls of the piping have oil with refrigerant mixed in...it will take a looooooooong time to boil the refrigerant out of the oil to obtain micron levels.

    This is not a new install nor is it a contamination clean up...its a common practice drier change.

  5. #18
    Join Date
    Jan 2010
    Posts
    6,327
    How about this one turn the service valve 180*

  6. #19
    Join Date
    Feb 2003
    Posts
    11
    You could turn the service valve around.
    Last edited by grimmus; 02-16-2010 at 02:18 PM. Reason: i see VTP99 got it first

  7. #20
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,449
    Quote Originally Posted by grimmus View Post
    You could turn the service valve around.
    Then there would be trouble servicing the liquid line if the situation arose.


    anyways I closed the king valve, pumped down the system, closed the service valve, replaced the dryer, brazed a schraeder into the line between the king valve and dryer, evacuated the dryer from that, opened all the valves and started it back up.

  8. #21
    Join Date
    Nov 2009
    Location
    Richmond, working under tarps
    Posts
    495
    So there is no real problem, with the way you did it?

  9. #22
    Join Date
    Mar 2007
    Location
    tx
    Posts
    1,088
    I guess the first thing I would consider in trying to decide about a good evacuation or not is why the filter change in the first place. If we were dry and free of contaminates, then why the filter change. I know things take time with a 6 or even 7cfm pump, but if you don't have the time to do it right the first time, where are you going to get the time to do it again? And who pays for the component failures because of a techs failures? Just go ahead and do what you know you should. Leave the solenniod calling(open), close your king valve on the reciever, pump the system down. You may even have to jump that low pressure switch a little to pull it on down. Open your system, make the dryer replacement, then pull a good evacuation. If time is the issue, put that pump on one unit when you get it sealed up, and go start pumping down one or two of those other units you were talking about. You sound like a guy who cares, or you would'nt be asking questions. Do what you have been taught is right and charge for as many hours as it takes to do it right.

  10. #23
    Join Date
    Mar 2007
    Location
    tx
    Posts
    1,088
    I see what you are sying about back flow, but your suction valve in the compressor will keep you from backflow after the low side is pumped down.

  11. #24
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,449
    Quote Originally Posted by surenuff View Post
    I guess the first thing I would consider in trying to decide about a good evacuation or not is why the filter change in the first place. If we were dry and free of contaminates, then why the filter change.
    The filter is being changed because the sight glass indicated moisture. I don't see how isolating the filter and then evacuating just that portion of the system after the change is any different than not isolating the filter and evacuating the whole lineset and evap, except that one method takes a heck of a lot more time. Either way the portion of the system that got opened is evacuated.

  12. #25
    Join Date
    Mar 2007
    Location
    tx
    Posts
    1,088
    Your the pro!!!!!!!!!! The one thing I have not figured out yet about this site, is why so many people will spend so much time asking questions and waiting for replies to questions that >>>>>by golly they already have all the answers to.

  13. #26
    Join Date
    Mar 2008
    Posts
    257
    Quote Originally Posted by surenuff View Post
    Your the pro!!!!!!!!!! The one thing I have not figured out yet about this site, is why so many people will spend so much time asking questions and waiting for replies to questions that >>>>>by golly they already have all the answers to.
    Because it always leads to the next question.....If he did this correctly, closed king valve, pumped down, closed suction serive valve, changed dryer and evacuated properly, maintaining power to the LLS, and pulling on both suction and liquid then he might find he's not holding vacume on the low side which would be causeing the sight glass to indicate moisture in the first place???? There is also the possibility that someone ahead of him did not evacuate properly causeing this indication of moisture...geee willicar

Page 2 of 3 FirstFirst 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event