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  1. #14
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    476
    No this isnt unseasonal for Wisconsin. I was under dressed probably. It was in the teens today. And I didnt front seat the suction service valve but I should have cause that would do it to.

    So from my experienced friends at hvac talk.com The head pressure is on the low side. You all seem to agree so I will go with that.

    Do you guys think this unit is possibly still undercharged since without a headmaster we would be condensing around 50 degrees. Possibly thats all the condenser can flood with the charge and thats the pressure translating to the Reciever. In this scenario the site glass could possibly still be full of liquid correct? You would think though after adding 10 lbs this would do something to the head pressure. I dont understand how I only have 22# in the suction line and 12 degrees superheat. At that low pressure I would think super heat would be high. I guess thought the suction pressure was a little higher when I initially started charging and the cooler was in the 40s than when I was done and it was down to temp.

    Oh another thing my original concern was the frost snow layer on the ditributors. There covered to the coil. Then theres just some light frost on the coil. Nothing major yet. Im always a little worried and anxious. Thanks, Dan

  2. #15
    Join Date
    Jan 2007
    Location
    maine
    Posts
    792
    Quote Originally Posted by dangpgt97 View Post
    No this isnt unseasonal for Wisconsin. I was under dressed probably. It was in the teens today. And I didnt front seat the suction service valve but I should have cause that would do it to.

    So from my experienced friends at hvac talk.com The head pressure is on the low side. You all seem to agree so I will go with that.

    Do you guys think this unit is possibly still undercharged since without a headmaster we would be condensing around 50 degrees. Possibly thats all the condenser can flood with the charge and thats the pressure translating to the Reciever. In this scenario the site glass could possibly still be full of liquid correct? You would think though after adding 10 lbs this would do something to the head pressure. I dont understand how I only have 22# in the suction line and 12 degrees superheat. At that low pressure I would think super heat would be high. I guess thought the suction pressure was a little higher when I initially started charging and the cooler was in the 40s than when I was done and it was down to temp.

    Oh another thing my original concern was the frost snow layer on the ditributors. There covered to the coil. Then theres just some light frost on the coil. Nothing major yet. Im always a little worried and anxious. Thanks, Dan
    If you front seat the suction the unit will pump down and if the pressure rises your valves in the compressor are bad and its probably not ur LLSV.. I just wouldn't shoot down the LLSV as the problem till i tryed that..

  3. #16
    Join Date
    Oct 2007
    Location
    The rainy state
    Posts
    172
    Does the condensor fan cycle with the comp? does the comp have a crankcase heater/ working? as to the frost on the distrubitor this should not be a problem if there is enough time from when the unit cycles off to back on. how much differentail on the control?

  4. #17
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    476
    I read you loud and clear on that. It could go either way I kinda just made an assumption while i was on the job. Thanks though for bringing that up. Didnt think of it and the check is very easy and could save me from wasting time ecspecially with the king valve not gonna work. Dan

  5. #18
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    476
    Yep the Condenser fan is one with the comp. Actually i never checked the crank heater. With a pump down it may not have one. Control is set to 25 psi cut in or high event and the differential is set to 20 psi. Unit dosent take real long to hit high event on off cycle. Thanks to you guys again. I know you all work long days already. Dan

  6. #19
    Join Date
    Oct 2007
    Location
    The rainy state
    Posts
    172
    even if it is a pump down it should have a crankcase heater, the reason i asked about the condenser fan cycling, i have seen outdoor units with the condenser fan running all the time. this creates problems with the refrigerant actually condensing at the comp. what cycles the LLSv? T-stat in the box? if so the differential you want is 10 deg. keep plugging along

  7. #20
    Join Date
    Jan 2007
    Location
    maine
    Posts
    792
    Quote Originally Posted by chilly123 View Post
    even if it is a pump down it should have a crankcase heater, the reason i asked about the condenser fan cycling, i have seen outdoor units with the condenser fan running all the time. this creates problems with the refrigerant actually condensing at the comp. what cycles the LLSv? T-stat in the box? if so the differential you want is 10 deg. keep plugging along
    10 degree diff on the t stat??????????

  8. #21
    Join Date
    Oct 2007
    Location
    The rainy state
    Posts
    172
    yes since he has no time clock for defrost. just like any undercounter cooler.

  9. #22
    Join Date
    Jan 2007
    Location
    maine
    Posts
    792
    I run almost all my coolers with 4 degree diff and no time clocks.. if the unit is sized correctly you r fine.. Ive never run an under counter with a 10 degree diff eather.. just use constant cut in stat

  10. #23
    Join Date
    Oct 2007
    Location
    The rainy state
    Posts
    172
    myself i had better luck with a t-stat similar to Penn Johnson a19bbc2 stat with a max setting of 8 deg, letting the pressure control run as low pressure cutoff and not try to control temp. the undercounter example was a bad example

  11. #24
    Join Date
    Jun 2005
    Location
    Las Vegas NV
    Posts
    1,152
    Quote Originally Posted by chilly123 View Post
    myself i had better luck with a t-stat similar to Penn Johnson a19bbc2 stat with a max setting of 8 deg, letting the pressure control run as low pressure cutoff and not try to control temp. the undercounter example was a bad example
    Dang chilly, I'm trying to think this out. The A19BBC-2 is a coiled air bulb t'stat. If your measuring supply temp, not return temp, then your setup is basically like a t'stat with a wide differential measuring the actually coil temp (embedded in the coil). Your just using a LPC and T'stat to do the job.

    Am I correct?

  12. #25
    Join Date
    Oct 2007
    Location
    The rainy state
    Posts
    172
    I use that stat in the return air,( behind the coil) for example if i want a 35 deg box temp I would set the stat for a 35 deg return air temp. with a max 8deg setting on the stat that puts me at 43 deg box temp at control cut in should be more that enough to defrost the coil. personally i prefer having a time clock. always like to be sure the dang thing will defrost. the down side to using off cycle defrost is if somebody monkeys with the t-stat the coils freeze up

  13. #26
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    476
    Its just a thermostat that controls the LLSV and a low pressure control cut in cut out. Im sure it does most likely have crank case heat. Thanks, Dan

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