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Wednesday, April 11, 2012

Home A/C Inspection

It is that time of year to get your A/C inspected.

Now, you could call the nearest HVAC certified contractor to come out and give your system the once over and charge you for many things he did not actually do.  He will tell you your charge was low and he had to clean the condenser and there was a mouse nest in it and they ate some wires or a part was bad...you get the idea - basically the equivalent of an auto repair shop taking advantage of people .
OR you can save a lot of money by doing it yourself.  

Here is a list of things to look for and check out.

The first thing you should do is give your condenser a good visual inspection. The condenser is the unit that sits outside your house, it houses the compressor that moves the refrigerant around the cycle.  The condenser should be level within 10 degrees, this will keep the oil and refrigerant where it is supposed to be.  Take the cover off of the electrical connection box and look for bare wires, mice like to make nests in here and chew the wires.  Open the disconnect box and look for mice nests and bare or loose wires.  Look the fan blades over for any damage. Look at the fins for damage and cleanliness, use a light bristled brush and clean any debris that has accumulated on the surface of the fins. Look at the suction line insulation and make sure there isn't any missing.

Check to be sure your condensation line coming from the "A" coil housing on your furnace is still connected and is still going to its drain. The "A" coil is the evaporator that the refrigerant travels through and is turned from a liquid to a gas as it absorbs the heat from the ambient air passing over the fins. 

 Look at the filter and be sure it doesn't need to be changed.  If there isn't sufficient air flow the evaporator coil inside your furnace will freeze up and there will be no cooling.

Now you should be ready to start the unit up for the first time this season. Switch the selector to cool on your thermostat and set to the desired temperature.  Be sure the disconnect is turned on. The condenser may take a minute to start up so you should have time to get outside by it to listen to how it starts.  listen for any growling or any noises that would indicate a hard start.  This will indicate that your compressor motor is nearing the end of it's life.  Watch to make sure the fan starts and runs at it's full speed.  Feel the suction line under the insulation and make sure it feels cool.  Also feel the liquid line and make sure it feels slightly warm, this could take a few minutes.

If there are inspection ports on your furnace before and after the evaporator, you can check to see what the temperature differential across the coil is, it should be approximately15° to 20° difference for a  regular DX coil in home Central A/C.  If there is not, you can make some by drilling a small hole after the plenum.  the plenum is the piece of duct work that sits directly on top of the "A" coil. thi   This should only be done if you are very confident of where the coil ends inside of the duct work.  If you accidentally puncture the coil you will loose the refrigeration charge, possibly hurt yourself, or others, and need to replace the coil, which is not cheap.  I do not recommend this if your are not confident.  However if you are confident and proceed, just put a small 1/8" hole in the plenum and push a meat thermometer or any thermometer that will fit in it, and see what the air coming from the coil is.  The thermostat will tel you what the temperature before the coil is.

If the temperature difference is way to low you probably WILL nee to call in an expert.  Be sure if you do that they can present you with a HVAC certified contractor license or logo of some sort before you let them touch your system.  there are a great many wanna be contractors out there, they may be cheaper but their work is cheap also.

I hope this will save you some money and that it may have taught you something along the way.

Please feel free to comment or ask any questions, and we will do our best to answer them.