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I heard that if you do not mind interruptions to your A/C unit, you do not need to pay around $100 for annual service. Is that true? Or will something bad happen if I do not get annual maintenance for my A/C unit?
 

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I heard that if you do not mind interruptions to your A/C unit, you do not need to pay around $100 for annual service. Is that true? Or will something bad happen if I do not get annual maintenance for my A/C unit?
If you aren't one to clean condenser units that may operate in adverse conditions, check condensate drain line function ( if applicable ) and you can find a tech that's willing to take his time, be thorough with a check-up, and write up his findings, it can be a good investment.
 

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maintenance is important but once a baseline is established there's no reason to put gauges on the unit year after year - a little refrigerant is lost each time.

it's still important to keep things clean, check drain lines, electrical/capacitors, etc.
 

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I'd be amazed if they're putting gauges on something for $100 (and if they are, I don't want that guy 'servicing' my stuff). my bet that would be a new air filter and maybe leaf blowing out the condenser. a proper coil wash probably takes more time than the $100 would cover.
 

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As noted above, clean the condenser coils with a hose and mild cleaner and make sure the condensate drain isn't clogged by putting some bleach down it. The pros will say do this every year but I believe that 2 is OK unless you have a very dirty environment. Otherwise if it is cooling and hitting the set temp you are good to go. The more anal among us will also check the temperature differential across the evaporator coil to see how the unit is performing. Also as noted above, gauges not entirely necessary unless your other checks suggest you have an issue.
 

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In NY we can hose off the condensing unit and ignore everything else and they last 20 to 25 years. In FL we get annual maintenance and they last 10 years.
 

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The more anal among us will also check the temperature differential across the evaporator coil to see how the unit is performing.
A normal differential can anywhere between 10 and 25 degrees depending on fan speed and humidity so it's not a very valid test alone. with other data it's useful.
 

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You can go two years in most areas unless whoever mows your yard decides to windrow it toward the condenser unit.

My newer high efficiency unit with its close fin spacing needs cleaning annually but it's easy to do with only a soft bristle brush, no sprayer or chemicals needed. It does require dismantling the housing for access though... takes about an hour and a half for the round trip. All the debris stay on the surface and doesn't get deep into the fins... comes off easily.
 

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Yup... when my A/C only system is working properly it sits around 19 degrees. If it dropped to 10 I'd be steaming and it would never shut off in summer.
No, when the humidity is very high the capacity shifts from actual cooling to dehumidification.

If the return air is like 70%+ humidity, a low temperature difference is very normal.

As the humidity level drops off, the difference increases.

You can also have a lower drop if the fan speed is set higher than normal but the unit is working just fine.

Rules of thumb can get you in trouble.
 

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No, when the humidity is very high the capacity shifts from actual cooling to dehumidification.

If the return air is like 70%+ humidity, a low temperature difference is very normal.
The latent heat that humidity represents fools lots of people into thinking there is something wrong with their A/C when it can't seem to keep up in the early evening when the humidity rises typically just after sundown. I have heard that a lot in the form of, "My god man, it's cooler outside than inside and the A/C just keeps running and doing no good." :wink2:
 

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My old condensing unit in NY had a cage around the coils Allowing for easy brushing the coils. My new unit has a louvered steel enclosure so I can’t get near the coils without taking it apart. I put window screening around it and the screen keeps the coils clean. My HVAC guy said it is ok as long as I keep it clean. I brush it off regularly (every day when poplar trees are shedding).
 
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LOL... we are talking about generalities here and steady state operations in "normal" conditions. Rules of thumb work just fine for that. And please don't assume that I don't understand the impact of humidity and latent heat on evaporation and condensation. And another good way to see how your system is performing is to watch your indoor humidity during a cycle, especially when you start it up after being away when the house is humid inside. This responds far quicker than the drop in temp and it should tick right on down.

No, when the humidity is very high the

capacity shifts from actual cooling to dehumidification.

If the return air is like 70%+ humidity, a low temperature difference is very normal.

As the humidity level drops off, the difference increases.

You can also have a lower drop if the fan speed is set higher than normal but the unit is working just fine.

Rules of thumb can get you in trouble.
 
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