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Posted by Dave Solly on August 22, 2005, 1:31 am
>
>>I have lived in this house since it was new, 20 years ago. This past
>> week, during the late afternoon, I would get condensation coming from
>> the air outlet closest to the air handler and right after the coil. I
>> remember reading on this group that this is probably caused by icing
>> of the coil. remembering that low air movement across the coil could
>> cause this, I changed the filter and this time used a filter that
>> would allow more flow ( I had one of those super duper ones that
>> wouldn't let any pollen through). For the next day or so, that seemed
>> to fix the problem. Now today, It has started again. I turned the AC
>> off for about an hour, then turned it back on and no more
>> condensation dripping from the outlet. I know, however, that it will
>> probably return in another couple of hours. It is presently 100
>> degrees outside. The humidity is about 40%. Inside the temp is 77
>> degrees with a humidity of about 33%.
>>
>> This is the situation. The compressor is out side. Everything else is
>> inside in the attic. Over the life of the AC, the filters have NOT be
>> changed out on a regular basis. For the first 15 years or so, I used
>> the el-chepo filters. Usually, when I did remember to change them,
>> they were clogged up with dust. Last year I had someone come out to
>> do a checkup. This was the first time in about 10 years. He measured
>> the flow from the vents and used the gauges (I have no idea what the
>> measurements were but he said the readings all looked good). He also
>> checked the temp of the air coming out of the vents. All was good for
>> the unit I had. He of course tried to sell me a new high effency
>> unit, but when we finished talking, the payback would be after I was
>> dead.
>>
>> So now I'm thinking that one of two things is wrong. Either the coil
>> is clogged up and won't allow enough air to flow through the coil and
>> it therefore freezes up, or the freon level is low(?). There seems to
>> be good air flow coming from the vents and the air is cool, but can
>> the air get around the coil? Or is it possible that some of the coil
>> is clogged and that's where the ice starts to form, and then it just
>> gets worse from there?
>>
>> I know I'm going to have to call an AC guy out, but I'd like to have
>> an idea of what else the problem could be.
>>
>> Thanks.
>>
>> Dave
>>
>>
>>
>
> Dave...first of all....ignore the comment about the stat being too
> low...turning the stat too low on a properly charged system does
> NADA...the system knows only on, or off, and going too low will NOT
> cause freezing on a properly charged and operational unit in summer
> temps...PERIOD.
>
> Now, you probably answered your own question, but its impossible to
> see it from here, however, your lack of normal service is screaming
> clogged coil....DO NOT LET YOUR AC GUY PUT ANY REFRIGERANT IN THE
> UNIT TILL HE INSPECTS THE COIL!!!!
> Most guys will come out, with only a manifold and a nice green tank
> and start juicing the unit..they never go inside, never take a lineset
> temp, never take a RH% reading indoors, never get a dew point...never
> do any of that and start to overcharge the unit, and then, WITHOUT a
> scale, they start to dump refrigerant into the unit and then, with NO
> WAY to know what they put in the unit, they proudly proclaim its
> working, and charge you for 3lbs of refrigerant that they got for next
> to nothing and charge you $45 a lb for it.
> Low airflow across the coil, due to dirt, mold, etc, will cause the
> pressure readings at the manifold to be, or appear low. (BTW, those
> pressures...mean NOTHING to a trained tech...hes looking for temps
> anyway) A dirty blower wheel will cause the same thing due to lack of
> airflow..lack of airflow, means lack of heat being transfered to the
> coil, and thus, lower pressures. IF the units not been serviced, its
> worth your while to get the evap properly cleaned, the condensor
> properly cleaned, and THEN have the tech look for the issue..chances
> are, if it is low, and the ONLY way hes gonna know is to check the
> coils, clean the coils, and go inside and take temp readings for
> starters...then its got a slow leak. Any legitimate company will check
> the coils while they are servicing the unit for leaks..and use a
> detector thats of decent quality...not soap unless its a question of
> moisture setting the detector off..and if hes got a decent one, like
> CPS, or LeBold, that wont happen anyway.
> 9 out of 10 leaks are at the service ports and can be repaired in
> seconds, not hours normally.
>
> Now...things you want to see..
>
> 1-Checking the evap coil, and cleaning if needed.
> 2-Taking temp readings of the suction line and return air temp indoors
> BEFORE adding a damn drop of refrigerant.
> 3-a SCALE under that green refrigerant jug, so he knows EXACTLY how
> much he put in....
> 4-a leak check if he adds any refrigerant.
>
> You will want to ask him how hes gonna check the charge, and if he
> says, by pressure, you can tell him to get on down the
> road..superheat, or subcool, and HE wont know till he checks your
> metering device in the evap.
>
> Now...if you want a gas-n-go.....then let him do whatever he wants,
> and dont do anything but pay him whatever he asks...LOL
>
>
>
Thanks for the info Steve. I'm printing it out.
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