Page 1 of 3 123 LastLast
Results 1 to 13 of 33

Thread: strange system

  1. #1
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107

    strange system

    I got a call,a walk in cooler in a convient store not cooling.found out that R short.charged to clear sight glass.the box temp cool down to 34F and cycling ok.
    Look at the system carefully,it has one comp but two condensers connected in series. One cond is water cooled,the other one ( is air cooled. One receiver downstream of the condensers. Two evap coils connected in parallel.each coil has a tev but both of the bulb not attach to the suction line but hang to sense the air.low side pressure only stay at 38psi max when the box temp at 40F. The SH was 36F at the comp, 25F at the evaps. It has no high side port to check pressure. The tevs covered with ice,but the coils were not.
    Anyway,the box temp is ok now,but this system so strange to me. Anyone has any idea? Thanks.

  2. #2
    Join Date
    Aug 2011
    Posts
    9
    is that a txv or tev

  3. #3
    Join Date
    Nov 2009
    Posts
    382
    Quote Originally Posted by coolair8 View Post
    is that a txv or tev
    Either way is acceptable to describe a thermostatic expansion valve.
    "Don't wish it were easier, wish you were better"

  4. #4
    Join Date
    Nov 2009
    Posts
    382
    Quote Originally Posted by markvilleman View Post
    I got a call,a walk in cooler in a convient store not cooling.found out that R short.charged to clear sight glass.the box temp cool down to 34F and cycling ok.
    Look at the system carefully,it has one comp but two condensers connected in series. One cond is water cooled,the other one ( is air cooled. One receiver downstream of the condensers. Two evap coils connected in parallel.each coil has a tev but both of the bulb not attach to the suction line but hang to sense the air.low side pressure only stay at 38psi max when the box temp at 40F. The SH was 36F at the comp, 25F at the evaps. It has no high side port to check pressure. The tevs covered with ice,but the coils were not.
    Anyway,the box temp is ok now,but this system so strange to me. Anyone has any idea? Thanks.
    It does sound a little strange. I have not seen a water and air condenser in series on a conventional system.

    Did someone hack it in as the system required more condenser surface?
    Was it piped to use either or? Even though that wouldn't be the way to do it properly.

    The world may never know what someone was thinking...

    But to the expansion valve issue, Think about what the purpose of the valve is and how it operates. The thermostatic element is one of the forces needed to make the valve operate properly. The bulbs need to be properly mounted and the superheats set as well as insuring that they are the proper size. For that matter, I would do a quick check to insure the system components are matched as well as the load.

    I am questioning the expansion valve sizing if the bulbs are hanging loose and you have 25* of superheat, especially if you have ice on the valves and the coils are clear. Are the valves too small??? Distributor/orifice sizing issue??? Some time needs spent figuring that out.

    Sounds like you have some work ahead of you on this one.

    BTW, what is the refrigeratant? How about temps and pressures? More info would be handy.
    "Don't wish it were easier, wish you were better"

  5. #5
    Join Date
    Jan 2010
    Posts
    5,812
    Sounds like a HACKS idea of heat reclaim.

  6. #6
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,308
    It's not common but I have seen a few. The water cooling is added as an afterthought once they find out the room the condensers are in is too hot for the condenser to operate properly. I'm guessing the tev's are sensing air because they may be undersized and the last guy to work on it figured by having them sense air they would stay wide open. You confirmed that with a25 degree evap SH.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    It was working when I left...
    Liberalism-Ideas so good they mandate them

  7. #7
    Join Date
    Jan 2010
    Posts
    5,812
    So there using water & electric to do condensing ? Sounds very energy efficient.

  8. #8
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,081
    With regards to the water-cooled condenser, my guess is this one was added after-the-fact, and was not a factory setup. They work pretty well if done right.

    Yes...they used to make what was called an Air & Water Cooled Condensing Unit. They were intended as a water-saver because many systems back in the dark ages were water-cooled using city water. When municipalities started billing for water usage, they became quite popular.

    Obviously those expansion valve bulbs hanging loose is a hack job. Verify that the valves (and the distributor nozzles) are properly sized and set up for R22 MT.

  9. #9
    Join Date
    Jun 2007
    Location
    Williamsport, PA
    Posts
    164
    I would keep working on this system. The txv bulbs flapping in the wind is a big red flag. I would check to see that all parts of the system are matched then go from there. The superheat should be next to nothing without the bulbs attached to the suction line. IMHO if you walk away from this system you will be replacing a compressor soon. Only way to get the most life out of the compressor is if it is operating of a properly set up system.

  10. #10
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    BTW, what is the refrigeratant? How about temps and pressures? More info would be handy.[/QUOTE]

    It's R22. It doesn't have anything for high side pressure measurement.

  11. #11
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    Quote Originally Posted by 2sac View Post
    It's not common but I have seen a few. The water cooling is added as an afterthought once they find out the room the condensers are in is too hot for the condenser to operate properly. I'm guessing the tev's are sensing air because they may be undersized and the last guy to work on it figured by having them sense air they would stay wide open. You confirmed that with a25 degree evap SH.
    The room is not very hot,but small.And a lot of stuff inside.

  12. #12
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    Quote Originally Posted by icemeister View Post
    With regards to the water-cooled condenser, my guess is this one was added after-the-fact, and was not a factory setup. They work pretty well if done right.

    Yes...they used to make what was called an Air & Water Cooled Condensing Unit. They were intended as a water-saver because many systems back in the dark ages were water-cooled using city water. When municipalities started billing for water usage, they became quite popular.

    Obviously those expansion valve bulbs hanging loose is a hack job. Verify that the valves (and the distributor nozzles) are properly sized and set up for R22 MT.
    the TXVs might be undersize since ice build up on them. But, I didn't see ice on the evap. If the TXVs didn't feed enough R to them, the suction pressure and temp would be lower, then ice will build up very fast, right?

  13. #13
    Some have good ideas. Get the system in the condition you know it should be in. Then you can start your troubleshooting. Sometimes the tech or the customer didn't fix the probleml

Page 1 of 3 123 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