Results 1 to 5 of 5
  1. #1
    Join Date
    Feb 2004
    Posts
    8

    lg dehumidifier defrost issue

    I have a lg d/u about 7 years old.it is cycling into defrost about every 8 minutes.the evap coil is lightly frosted just proir to defrost.initally I felt it was a refrigerant issue.its a r22 unit.I recovered unit,flushed and weighed in the correct charge,with no change.(and yes I'm epa cert).I get a suction pressure of 50 psi, a line temp of 27 deg.in a normal a/c sytem that would certainly be a problem but I know d/u's work differently.does that pressure seem low for a d/u?
    has anyone else had an issue with defrost control cycling in and out rapidly like this .is it more likely that a sensor or defrost control is failing or is the unit cycling because it frost's up to quickly.also when its in defrost the fan turns off.the compressor keeps running and the reversing valve engages.the manual says the fan should stay running during defrost and the compressor shuts down.so why have a reversing valve?

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,642
    What is the temp/%RH of the air entering the dehu?
    What are your expectations of ^F/%RH?
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    Feb 2004
    Posts
    8
    air temp is 73, rh is 54%.

  4. #4
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,642
    If the coil is freezing on 80-90% of surface, expect air flow problem. Mabe fan is on low speed or ? If coil is not covered with frost, try a little more refrigerant. Also, is it possible that your meter is not accurate? You may have a lower %RH than you think.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  5. #5
    Join Date
    Feb 2004
    Posts
    8
    thanks for the reply,however its not an airflow issue,nor is it a r/h% issue.the coils are lightly frosted on the ends but never completely over.after checking the obvious, I installed a peircing valve and checked the charge.I felt 50 psi was to low.rather than just topping of I recovered ,installed service valves and weighed in the factory charge and got the same pressure.our other d/u's frost on startup but go away after a few minutes.this never gets to that point it goes into defrost before it levels outs.I did add 2 oz,( only 8.5 factory),and the pressure only climbed a few psi.the more I think about it ,I'm leaning towards a defrost control issue.its been a good old unit but it might be time for retirement.the parts end up costing more then a new unit.

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