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  1. #1
    Join Date
    Mar 2007
    Posts
    2

    Starting up outdoor walkins

    Just wondering if anyone has a rule of thumb, when starting up an outdoor walkin box with an air cooled condenser what your head pressure should be corresponding to the outdoor air temp?

  2. #2
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,080

    The rule of thumb is.....

    ....charge it until you clear the sightglass, look at your discharge pressure and that's what it's supposed to be.

    There's actually a bit more to it than that like whether or not you have a Headmaster and such, but that's it in a nutshell.

    If all else fails, read the installation instructions.

  3. #3
    Join Date
    Mar 2007
    Posts
    2
    Not to be a pain but, hypothetacally speaking, what if there were no sight glass or installation instructions? No head master controll either...???

  4. #4
    Join Date
    Aug 2006
    Posts
    442
    What is your outdoor ambient? Must have some type of fan cycle control.

  5. #5
    Join Date
    Aug 2006
    Posts
    442
    What refrigerant?

  6. #6
    Join Date
    Dec 2006
    Location
    Litchfield,Il
    Posts
    565
    I would definitly charge it in the morning and the condensing station should have a data plate that states the correct charge being that it is a new unit. When the sun is high and the temp is boiling -- getting a correct reading is a bastard--
    If your not getting the results you desire then change. People change from either desperation or inspiration.

  7. #7
    Join Date
    Jan 2006
    Location
    Near Atlanta, GA.
    Posts
    14,433
    Quote Originally Posted by assp8 View Post
    Not to be a pain but, hypothetacally speaking, what if there were no sight glass or installation instructions? No head master controll either...???
    It would depend on the type of refrigerant, outside temperature, load conditions, and the size of the condenser in relation to compressor capacity.

    That's about all I can tell you without specifics.

    Oh and...unless you live in a very warm climate you need some type of head pressure control.

  8. #8
    Join Date
    Aug 2006
    Posts
    442
    Quote Originally Posted by luskys a/c View Post
    I would definitly charge it in the morning and the condensing station should have a data plate that states the correct charge being that it is a new unit. When the sun is high and the temp is boiling -- getting a correct reading is a bastard--
    Most condensing units Ref. wise do not have a weight stamp on it

  9. #9
    Join Date
    Mar 2007
    Posts
    1

    need help with heat controller 90% ( roll out fault)

    i did a call for a friend, also self employed, but only installs. he put in a heat controllerglua or gldh 120.000 btu. flashing rollout, reset, unit put in 1-month ago, place is gutted, unit in attic. guy owns place says it never worked right. they called me back tonite same thing. i read install instructions, furnace mounted horizontal to right discharge, but on instructions it says important, do no not install horizontal right only left side supply. drain from secondary exchanger was left as if installed upright, drain from secondary is on very top left side. secondary drain is not at bottom of burner area, where the install instructions say when horizontial install only can be install with left side supply. the roll out thats popping is bottom one in horizontial position, inducer motor is below secodary x-changer, could this be the cause of rollout, bottom 2 burners in secondary have water creating cloogged xchanger causing rollout. al,ost all my work over last 21 years has been heat pumps, and 80% furnaces. thanks hope you can understand post, in a rush

  10. #10
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,080

    Hypothetically???.........

    Quote Originally Posted by assp8 View Post
    Not to be a pain but, hypothetacally speaking, what if there were no sight glass or installation instructions? No head master controll either...???
    If it were my job to start up this system, first I'd place a curse on the SOB that neglected to install a sightglass and a head pressure control.

    Then I'd download the instructions and install them myself and do the startup.




    Now back to reality............

  11. #11
    Join Date
    Dec 2006
    Location
    Litchfield,Il
    Posts
    565
    Yeah, I wondered -- it makes sense due to different run lenths- I think they should have a scale plate.
    If your not getting the results you desire then change. People change from either desperation or inspiration.

  12. #12
    Join Date
    Aug 2006
    Posts
    442
    they are too cheap to provide the ref. instead you get dry nitrogen

  13. #13
    Join Date
    Dec 2006
    Location
    Litchfield,Il
    Posts
    565
    I have never installed a outdoor walk in. Does the mfg. send you some type of guide to what charge would be adequate to how much copper you have down?I mean - if the remote unit was further away from the box than the norm.?
    If your not getting the results you desire then change. People change from either desperation or inspiration.

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