Page 1 of 2 12 LastLast
Results 1 to 13 of 31

Hybrid View

  1. #1
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,399

    Pull a vacuum against a solenoid valve?

    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.

  2. #2
    Join Date
    Sep 2001
    Location
    Rochester, New York
    Posts
    1,385
    Wouldn't front seating the service valve gain access between the king valve, drier and sightglass???

  3. #3
    Join Date
    Jan 2010
    Posts
    6,232
    Can you pump it down ?

  4. #4
    Join Date
    Sep 2007
    Location
    NH
    Posts
    1,148

  5. #5
    Join Date
    Jun 2009
    Location
    Upstate SC
    Posts
    1,439
    Are you changing cores or sealed driers? Couldn't you just put in a service port while you're doing the work?

    Sorry guys if none of this is relevant..... See edit
    Last edited by jdblack; 02-11-2010 at 08:05 PM. Reason: Didn't realize I was in ice making section

  6. #6
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,567
    You ain't gonna get a micron vacuum, but you will get most of the air out.


    I think you'd be better off pumping it down as other have suggested.

  7. #7
    Join Date
    Jun 2004
    Location
    Location:Raleigh NC
    Posts
    9,619
    I agree with pumping it down and/or also adding a service port
    If you help others then you are a Success

  8. #8
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,399
    I can pump it down to the reciever, no problem. The problem is pulling the vacuum. neither valve provides access to the filter/drier when they're in the position that isolates the filter. I could midseat the service valve, but that would require that the solenoid can prevent backflow.

    heres some pictures that I took a long time ago for another reason. If you combine what you see in the two pictures, you can figure out the piping arangement.


    Name:  IMG_1923.jpg
Views: 156
Size:  198.2 KB
    Name:  IMG_1925.jpg
Views: 137
Size:  153.3 KB

    I'm thinking the best thing to do might be to just braze a schraeder fitting right into the liquid line between the two valves.

  9. #9
    Join Date
    Sep 2001
    Location
    Rochester, New York
    Posts
    1,385
    Too bad they don't make liquid line driers with access ports.

    I've pulled many a vacuum against a liquid line solenoid valve with out any problems. I don't recommend, but it's surely been done before.

    Is it possible to just front seat the suction valve on the compressor once you pump it down??? If not, I'd do like you say, and install a valve in the liquid line.

  10. #10
    Join Date
    Feb 2010
    Location
    butler pa
    Posts
    1,073
    just sweat in an acess tee

  11. #11
    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.

  12. #12
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,399
    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.

  13. #13
    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.

Page 1 of 2 12 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