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  1. #1
    Join Date
    Jul 2011
    Location
    Delaware
    Posts
    29

    Is there an add-on Ice Sensor for existing home AC units?

    The reason I ask is that my elderly Mother lives alone in her house in Florida, and too often she has suffered no-cooling due to icing of the A coil.

    Most of the trouble for the last 3 years was due to an improper T-sat installation where the service did not change the dip switces for a single stage t-sat. The fans speed stayed on the low setting, and icing was every 5 mos on average.

    Now, after the compressor was beat to death, she has a new system as of last year, and once again no cooling due to a 6" thk build-up of ice on the a-coil, that took overnite to defrost, and in total, made for a day and a half of humid 85F in the house!

    It seems to me that a simple resistive or K-type temperature sensor could be mounted on the side of the A-coil where the ice starts to build, that turns off the compressor only until the ice melts, to prevent the extreme build up that she has now. She would notice the rise in temps, especially since I got her a hand held radiant gun with "lazer targeting" to read a typical flow temp off the grill (not exact grill temp due to distance).

    Any help would be greatly appreciated,

    Kevin

    PS: I installed an undersized 2.5T Sears unit with precharged lines 25 years ago on my home in Delaware, and never had a leak ...... but never had Florida anual temp & humidity.

  2. #2
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,006
    Call some local contractors & see if they will install one.

    The coil should not be icing-up; have them check the airflow CFM & the refrigerant charge; something is causing the icing-up, unless she is operating the thermostat at too low a temp when its cool outdoors; perhaps at night.

  3. #3
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Sounds like you probably have either an equipment issue or low airflow from undersized ductwork or a oversized unit.

    Can you adda freeze stat? Yes, they clamp on to the lineset and interrupt the call for cooling to the outdoor unit. But it's a band aide. You shouldn't need it.

    You mgith start wit ha less restrictive air filter. Thsoe filtrete filters are oftne too restrictive. Also the coil might need ot be cleaned.

    Also, newer equipment

  4. #4
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,470
    Freeze stats are used for low ambient cooling applications. Your problems seems to be either a refrigerant or airflow problem. Have a tech come and look over your system and see what they suggest or find wrong.

  5. #5
    Join Date
    Jul 2011
    Location
    Delaware
    Posts
    29
    Thanks for the reply udarrel.

    She has a contract with Aztil, who install the new matched system last year.

    I had them check the fan speed and it was correctly on the high setting (2 speed).

    Running with it cold out is not a problem in Florida right now.

    The tech just stopped by and turned the compressor back on (was just on fan to thaw the ice overnite). I had Mom check the outdoor condensate discharge and it's dry. It's about 85 in the house with about 90% rel humid. Either the pans are filling or there is still ice-up.

    So there is a standard ice sensor that I've described?

    Thanks again

  6. #6
    Join Date
    Jul 2011
    Location
    Delaware
    Posts
    29
    I know it should not happen. They have been down there about 20 years, and the 2 prior 5T systems never had icing issues, so I think the duct sizing is ok.

    I know the sensor should not be needed, and I hope after it is installed it is never needed. But when you are 1000miles away, a "should not need it" device sounds perfect for me right know, after a 6" build=up.

    The filter is a cut porous material with low resistance to flow. There is a germ type filter with matrix + UV light.

    Last readiings by Mom were 69 exit ducts ( from relative floor reading) and 80 in house.

    Thanks for all the replies.

  7. #7
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,006
    It is difficult to get enough airflow CFM for a 5-Ton residential A/C.

    Equipment may be oversized with inadequate airflow; or the charge may be somewhat low; could be other factors as well.

    As motoguy128 suggested, use filters that have less resistance pressure-drop to get more airflow.
    Also; Filters may not be getting replace often enough!

  8. #8
    Join Date
    Jul 2011
    Location
    Delaware
    Posts
    29
    She/they have had 5T units for 20 years w/o icing issues until the last 3 years, when a new AC 5T system was installed and the made a mistake on the dip switch settings that kept the airflow too low. This another new 5T unit installed last year. It had a low charge, and tech filled it this morning .. another teah is going to find the leak.

    The filter is not pleated ... cut porous sheet. Replaced on maint sched.

    Thanks for the tip on the Freeze stats. It should not be needed but I sure want it after par boiling my 89 yo Mom for 2 days in the Florida's summer heat ! Basically she was told a tech would be there this morning, first call .... one shoed up to fill at 12n, not to fix. The fixer is supposed to be there at 3:30 ( 12n promised).. we'll see.

    If she had a freeze stat, she would have noticed the temp rise and made a call before ice was excessively thick.

    It must be brutal to be an AC tech in Florida !

  9. #9
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,006
    Elderly folks ought be provided priority as high heat conditions can threaten their lives!

  10. #10
    Join Date
    Jul 2011
    Location
    Delaware
    Posts
    29
    All of you that suspected the duct size might be too small for a 5T unit win a prize ... She has a 3T unit ! My bad, ex GF had a 5T.

  11. #11
    Join Date
    Jul 2011
    Location
    Delaware
    Posts
    29
    The Tech found a leak where the power cable enters the sealed compressor. System was topped off and new compessor is scheduled to be installed 1st call tomorrow. I told the dispatcher that it was imperative not to let the appontment slip, as the it will be leaking a long night, and I don't want to start the ice build-up cycle.

    I hate to bother you more, but why did a 1 year old compressor start leaking like that? It's a Rheem system, and I think they put the compressor in last year, vs a new outdoor unit. Damage during installation?

  12. #12
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,470
    Maybe the same thing that killed the other compressor.

  13. #13
    Join Date
    Jul 2011
    Location
    Delaware
    Posts
    29
    Quote Originally Posted by jtrammel View Post
    Maybe the same thing that killed the other compressor.
    Don't think so.

    Shortly after they (Atzil) installed a new system with a new programable t-stat, 3 years ago, my Mom asked them to put her old analog t-stat back in. After that, she had two years when the A-coil froze up every 5 months on average.

    I found the dipswitches on the air handler were not reset when they put the old t-stat back in, and the blower had only run at low speed. Running with ice all the time shook the heck out of the compressor, and the tubing attached to it, resulting in lots of tubing leaks. It even shook the ancor bolts loose and on the floor of the outdoor unit.

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