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Central air issue...

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So i have a very old system (not sure of the brand since all the labels are completely gone or faded). It is 29 years old system that is probably about 1.5-2T (again all labels are completely faded and unreadable). The system worked fine without issue until this summer, when it started to cool insufficiently. I noticed one spot along the line feeding into the inside coil that is uninsulated had a big ice chunk on it from condensing and freezing i am guessing, also the line feeding on the outside unit was pretty frosty. I had 2lbs of R22 added, but that only seemed to increase the pressure by around 10psi on both hot and cold side.

The system did seem to work better, but a few days later it seems to be having same issue. Is there are leak or could there be some clog somewhere in the refrigerant lines?

I have a clean air filter in and I cleaned the blower hamster wheel well to ensure that is working fine too.
neilc

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,419
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    Probably a leak somewhere -- at that age, not surprising. However, that said, at that age and using R22 you will go broke tying to recharge it and keep it in good shape.

    Maybe it's time for a new one? Maybe even a heat pump?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    HVACNUT
  • mattmia2
    mattmia2 Member Posts: 9,734
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    Sounds like you need a better tech. Was the is only on a small section of the evaporator and the rest warm? Is is an orifice or a txv system (probably orifice at that age)? Depending on system type what was the superheat or subcooling? What was the airflow through the indoor coil? If it is an actual leak then probably time for replacement unless it is obvious and simple to fix. If it is an airflow issue because of a problem with the blower or the fain then that is probably worth fixing.
    genericnj
  • genericnj
    genericnj Member Posts: 74
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    thanks @mattmia2 I remember your name from another issue you helped me with in the past!

    Honestly I know very little about this system, I looked at the evap coil on the inside of the house and it wasn't covered by ice and had some water below it and looked clean. But one of the lines running to it had frozen condensate on it. I'm going to have another tech come in and take a look. Unfortunately this is in a rental unit that loses me money each year but I cannot sell it because i would lose even more so this is just a painful hassle...

  • HVACNUT
    HVACNUT Member Posts: 5,858
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    You can't legally add R22 knowing there's a leak. It's 29. Replace it, along with the line set or you won't be able rent it or sell it.
    pecmsg
  • mattmia2
    mattmia2 Member Posts: 9,734
    edited July 2023
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    If the system contains under 50# of refrigerant you can charge a leaking system under any circumstances. If it is over 50# it can only have a certain leak rate. We don't know that it has a leak, it sounds like it may be an airflow issue(and also is now overcharged) but we don't have enough information.

    https://www.epa.gov/section608/stationary-refrigeration-leak-repair-requirements

    BTW, a cheap tech is going to cost you more than a tech that knows what they are doing here.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,607
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    problem is with a 29-year-old unit most techs will "gas and go" it's not right they should find the leak if it has one and either fix it or if it's in a coil, they may deem it unrepairable. And as @mattmia2 said we don't even know if it has a leak, it may well be a fixable problem.

    your location is important in the northeast units can last 40 years because they only get run hard for a few months......maybe not even that this year.

    if your down south and have a 29-year-old unit its probably time to replace it ......if the fix is expensive,

    bottom line.... not enough information
  • pecmsg
    pecmsg Member Posts: 4,881
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    HVACNUT said:

    You can't legally add R22 knowing there's a leak. It's 29. Replace it, along with the line set or you won't be able rent it or sell it.

    with less than 50#'s you can keep adding until the bank account goes empty!
    HVACNUTSTEVEusaPAmattmia2
  • genericnj
    genericnj Member Posts: 74
    edited July 2023
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    The unit is in northeast (NJ). Before adding 2lbs r22, the pressure was just below 50psi and after 2lbs was about 58psi. the Unit services 3rd floor apartment of a condo building. It has never had any freon added to it in the 29 yrs. The evap coil was not frozen and was clean with water on bottom of it. Just the line feeding to it had a spot with chunk of ice where it was uninsulated. There is also water drpping from behind the siding where the lines go up to the apartment, but the lines going to the outside unit were not frozen. Also, cleaned the blower and changed filter in case there were restrictions, but that did not help. Sorry I don't really have much more info, or if I do, i'm not sure what info may be relevant.
  • genericnj
    genericnj Member Posts: 74
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    SuperTech
  • MaxMercy
    MaxMercy Member Posts: 514
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    your location is important in the northeast units can last 40 years because they only get run hard for a few months......maybe not even that this year.

    Good point. I'm in the Northeast U.S. and both my units (two story, two systems) are 30 years old and still running perfectly. A fan here or there, a couple of capacitors, one relay (they call them contactors these days?) and they're still humming along. The upper floor of course gets more use and the bottom very little since coolish dry air settles on the first floor (we keep the windows closed when we run the upper air), but the upper floor gets maybe 6 weeks total out of the year, the bottom half that or less.

    John
  • HVACNUT
    HVACNUT Member Posts: 5,858
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    pecmsg said:
    You can't legally add R22 knowing there's a leak. It's 29. Replace it, along with the line set or you won't be able rent it or sell it.
    with less than 50#'s you can keep adding until the bank account goes empty!
    That doesn't make it right. If it's a leak, find and repair. If it's in the evaporator or condenser, replace If R22 IMO.
  • mattmia2
    mattmia2 Member Posts: 9,734
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    Was that cap on the access valve always missing? if the caps aren't out on and seated with a wrench the charge will eventually leak out of the access valves.(same goes for the caps on the service valves)
  • pecmsg
    pecmsg Member Posts: 4,881
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    HVACNUT said:
    pecmsg said:
    You can't legally add R22 knowing there's a leak. It's 29. Replace it, along with the line set or you won't be able rent it or sell it.
    with less than 50#'s you can keep adding until the bank account goes empty!
    That doesn't make it right. If it's a leak, find and repair. If it's in the evaporator or condenser, replace If R22 IMO.
    Releasing refrigerant isn’t right. 
    Your point?


  • mattmia2
    mattmia2 Member Posts: 9,734
    edited July 2023
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    pecmsg said:

    HVACNUT said:

    You can't legally add R22 knowing there's a leak. It's 29. Replace it, along with the line set or you won't be able rent it or sell it.

    with less than 50#'s you can keep adding until the bank account goes empty!

    HVACNUT said:


    That doesn't make it right. If it's a leak, find and repair. If it's in the evaporator or condenser, replace If R22 IMO.

    I posted the link to the epa information page which has a link to the actual rule.
  • mattmia2
    mattmia2 Member Posts: 9,734
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    MaxMercy said:


    A fan here or there, a couple of capacitors, one relay (they call them contactors these days?) and they're still humming along.
    John

    It is a power systems vs electronics things. In power systems they tend to be called contactors, in electronics they tend to be called relays. Size is a factor too, no one is calling a 2 a control relay a contactor.
  • pecmsg
    pecmsg Member Posts: 4,881
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    mattmia2 said:
    pecmsg said:
    You can't legally add R22 knowing there's a leak. It's 29. Replace it, along with the line set or you won't be able rent it or sell it.
    with less than 50#'s you can keep adding until the bank account goes empty!
    That doesn't make it right. If it's a leak, find and repair. If it's in the evaporator or condenser, replace If R22 IMO.
    I posted the link to the epa information page which has a link to the actual rule.
    The rule is
    less than 50#’s total charge keep recharging. 

    I don’t agree

    i also don’t agree with releasing refrigerant. 

    Those are facts
  • mattmia2
    mattmia2 Member Posts: 9,734
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    So the suction line was icing, it wasn't icing near the evaporator (indoor coil).

    I am far from the expert on this but i'll take a stab.
    That means there was still liquid refrigerant at that point.
    I think that would have to come from either overcharged or insufficient load on the system. in this case either the blower not running at the right speed, blower clogged, inlet side of the evaporator clogged with dust, bypass if outlet to inlet somehow, registers closed off or blocked with stuff or even paint.

    what did they measure for airflow through the coil and temps of the return and discharge?
  • pecmsg
    pecmsg Member Posts: 4,881
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    Any ice on the suction line means it’s below freezing. That’s an issue. 
    Short of refrigerant. 
    Restriction air flow. 

    Can’t see from here. 
  • mattmia2
    mattmia2 Member Posts: 9,734
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    pecmsg said:

    Any ice on the suction line means it’s below freezing. That’s an issue. 

    Short of refrigerant. 
    Restriction air flow. 

    Can’t see from here. 
    How can starving of refrigerant cause icing on the suction line? Wouldn't it be all vapor somewhere in the evaporator?
  • pecmsg
    pecmsg Member Posts: 4,881
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    mattmia2 said:
    Any ice on the suction line means it’s below freezing. That’s an issue. 
    Short of refrigerant. 
    Restriction air flow. 

    Can’t see from here. 
    How can starving of refrigerant cause icing on the suction line? Wouldn't it be all vapor somewhere in the evaporator?
    Short of charge the suction pressure drops below 32*. The coil freezes!
    MaxMercy
  • pecmsg
    pecmsg Member Posts: 4,881
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    pecmsg said:
    mattmia2 said:
    Any ice on the suction line means it’s below freezing. That’s an issue. 
    Short of refrigerant. 
    Restriction air flow. 

    Can’t see from here. 
    How can starving of refrigerant cause icing on the suction line? Wouldn't it be all vapor somewhere in the evaporator?
    Short of charge the suction pressure drops below 32*. The coil freezes!
    Low air flow can cause the same symptoms 
  • mattmia2
    mattmia2 Member Posts: 9,734
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    pecmsg said:


    mattmia2 said:

    pecmsg said:

    Any ice on the suction line means it’s below freezing. That’s an issue. 

    Short of refrigerant. 
    Restriction air flow. 

    Can’t see from here. 
    How can starving of refrigerant cause icing on the suction line? Wouldn't it be all vapor somewhere in the evaporator?

    Short of charge the suction pressure drops below 32*. The coil freezes!

    sure, i see how it would happen in the evaporator, part of it is frozen and it is warm after that point. Because of the low suction pressure the temp of the liquid refrigerant is below freezing. I don't see how liquid refrigerant would make it to the suction line if the charge is low because it has all evaporated before it exits the evaporator. I'm not saying it isn't possible, i just want to understand how if it is.
  • pecmsg
    pecmsg Member Posts: 4,881
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    It freezes as it comes in and continues at it goes thru!

    If the pressure is "Above" the SSP it wont freeze!