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    high head pressures (5 Posts)

  • Paul Paul @ 5:31 PM
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    high head pressures

    i have run into several goodman r22 units 15 to 20 years old that seem to have high head pressure on hot days.most in range of 270 to 325 and no complaints of cooling problems and good super heat, temp. drop condenser splits ctc. any thoughts?condensers on top of cabinet are hot and cleaned and or checked coils.just curious as the market is saturated in homes with these 10 seer condenser units with piston coils and have seen many with this higher head pressure and hot condenser but cooling ok.is this something with this model? i dont see this with other brands at same age area.i cant believe all these would be non condense ables, dirty coils etc.
  • Spence Spence @ 8:47 AM
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    Hot OD Units

    My best guess at the moment, since your SH is within reason, is that you have a relatively small condensing coil with not much surface area. Since about 85% of the coil should be condensing, the superheated vapor (about 15%) would have to be quite high to allow enough time for the ambient air to convert it to a full column of liquid (about 5%). And, some of the older coils did not have multiple passes either. With this in mind, one could assume the hot gas going into the coil could easily be 225 degrees or more; higher with a hotter day. As an experiment, check the hot gas line temperature before the pass manifold and then check each pass that enters the coil and compare it to units that are the same vintage yet not frying like the Goodman.
  • Techman Techman @ 10:31 AM
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    hi pressurers

    Why not go to your truck and get the garden hose/nozzle, take the cond unit apart wash it inside to out, then out to in, for 4-5 times, reassemble, start and run, wait 10 minutes for the wet cond coil to dry and compare readings! Then you will see! I agree ,check the discharge line temp( 1"-6" away from the comp), 225*F is the MAX temp allowable ,according to Copeland! At higher temps the oil starts to break down  ,along w/ the comp.
    This post was edited by an admin on August 3, 2013 10:33 AM.
  • RJ RJ @ 12:43 PM
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    coil cleaning

    Techman has the right idea,  even though the cond. coil looks clean,  washing out the coil with a hose and some coil cleaner will alot of times drop the head press.  15-25 psig,  watch all that dirty water run out
    RJ
  • unclejohn unclejohn @ 10:29 AM
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    If you look

    Real close at those Goodman coils from that era the fins are not flat. They have little perferations in them so the air passes through the fins as well as over them. Sounds like a good idea but really tuff to clean. No matter which way you hose out the dirt and lint [ why is the dryer vent always next to the condenser ] hang up on those holes.
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