Page 1 of 2 12 LastLast
Results 1 to 13 of 24
  1. #1
    Join Date
    Apr 2010
    Location
    Ontario
    Posts
    474

    Charging by sight glass

    When charging a refrigeration system by sight glass and its been off for hours, the case is warm. Do you clear the sight glass as soon as you can when you first restart the system, or let the case/product come down to its design temperature range and then finish charging to clear the sightglass.
    ENJOY THE RIDE

  2. #2
    Join Date
    Mar 2010
    Location
    Morgan Hill Ca.
    Posts
    1,219
    Quote Originally Posted by Peztoy View Post
    When charging a refrigeration system by sight glass and its been off for hours, the case is warm. Do you clear the sight glass as soon as you can when you first restart the system, or let the case/product come down to its design temperature range and then finish charging to clear the sightglass.

    Technically when the case is "warm" the system is overloaded, the sight glass is not there for charging, your thermometer is....

    In all seriousness, it depends on much more than what you wrote. Receiver?, TXV?, Cap tube?, type of refrigerant?...

    Not as cut and dried as you are trying to make it.

    GT
    If a day goes by and you have learned nothing, I hope you got a lot of sleep.

  3. #3
    Join Date
    Jan 2010
    Posts
    6,300
    Is it a indoor or outdoor condensing unit ? This could make a big difference.

  4. #4
    Join Date
    Apr 2010
    Location
    Ontario
    Posts
    474
    TXV, receiver, R22, reach in cooler.
    I was thinking when you first start up the txv would be fully open because of the high load.
    Later as the cooler comes down to temperature the txv would be more closed, the liquid line would have more refrigerant backing up in it, the sight glass would then clear when the system was running in its normal range.
    ENJOY THE RIDE

  5. #5
    Join Date
    Apr 2010
    Location
    Ontario
    Posts
    474
    Air cooled condensing unit in the ceilling.
    ENJOY THE RIDE

  6. #6
    Join Date
    Jan 2010
    Posts
    6,300
    Is it a pump-down system ?

  7. #7
    Join Date
    Mar 2010
    Location
    Morgan Hill Ca.
    Posts
    1,219
    Quote Originally Posted by Peztoy View Post
    TXV, receiver, R22, reach in cooler.
    I was thinking when you first start up the txv would be fully open because of the high load.
    Later as the cooler comes down to temperature the txv would be more closed, the liquid line would have more refrigerant backing up in it, the sight glass would then clear when the system was running in its normal range.

    This would be accurate.... Hence why I said the system would be overloaded.. So I guess to answer your question, the charge should be verified when the box is close to set point, which in essence is where it will be running most of the time.

    GT
    If a day goes by and you have learned nothing, I hope you got a lot of sleep.

  8. #8
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,622
    Quote Originally Posted by Peztoy View Post
    TXV, receiver, R22, reach in cooler.
    I was thinking when you first start up the txv would be fully open because of the high load.
    Later as the cooler comes down to temperature the txv would be more closed, the liquid line would have more refrigerant backing up in it, the sight glass would then clear when the system was running in its normal range.

    Correct
    Officially, Down for the count

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

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  9. #9
    Join Date
    Jul 2007
    Location
    Mount Airy, MD
    Posts
    7,281
    Thread relocated to the refer section

  10. #10
    Join Date
    Feb 2001
    Location
    Anaheim, CA
    Posts
    65
    Make sure that this system does not have a suction to liquid line sub-cooler. I once had trouble clearing a sight glass on an R-12 system in the same manner. I discovered that the sub-cooler had internally ruptured and hp liquid was short circuiting into the suction line.

  11. #11
    Join Date
    Jul 2012
    Location
    Western KY
    Posts
    1,221
    Txv needs full column of liquid regardless of box temp. Full glass is not nessisarily full charge with receiver. Hot box and warm ambient charging to full glass will leave you grossly undercharged.

  12. #12
    Join Date
    Aug 2012
    Location
    willowick ,oh
    Posts
    261
    I see everyone forgot the fact that its a reachin. It more than likely has a factory charge on the nameplate. If not then call the manufacturer. And dont say im just topping it off. thats like putting a bandaid on a compound fracture. If the unit is twenty years old with its second compressor in it then give a nice quote to fix it properly.Pull the charge and give it the factory charge. Dont rely on sight glasses. Especially when it was added in by the hack before you.

  13. #13
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,595
    Quote Originally Posted by heresjohnnyb View Post
    I see everyone forgot the fact that its a reachin. It more than likely has a factory charge on the nameplate. If not then call the manufacturer. And dont say im just topping it off. thats like putting a bandaid on a compound fracture. If the unit is twenty years old with its second compressor in it then give a nice quote to fix it properly.Pull the charge and give it the factory charge. Dont rely on sight glasses. Especially when it was added in by the hack before you.
    That is not necessarily true. I have a freezer at a gas station that is a reach in display case with the condenser outside. It is most certainly not a factory charge situation.

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