Air Conditioner Trouble Shooting
Posted: Sunday, April 01, 2007
by Terry Manlick
HVAC Maintenance & Supplies
Before you call a air conditioning service repair man to check your air conditioner that's not cooling you may want to check some of these possible causes. First and most obvious is to be sure your system air filter is not restricted. In many cases this will cause your evaporator or indoor coil to freeze up. If the system has a fan v-belt make sure it is not cracked broke or slipping. If the evaporator coil is froze up you may notice condensate leaking in and around the furnace, air handler or window type A/C unit. Another more apparent sign would be actually seeing ice build up on the coil or refrigeration lines connecting the evaporator and condenser.
It is possible that a power surge or electrical storm could also cause a breaker to trip and once you reset it the system will be fine. Another common cause for the condenser not functioning is a broken or shorted low voltage wire. Mice and other rodents will tend to chew though these wires. The low voltage wire is typically a small two conductor wire that runs along side the refrigerant lines. If the condenser is running but not cooling you may want to clean it. This can be done by turning off power to it, then wet it down with a garden hose. Apply a air conditioning coil cleaning solvent to the coil surface. Convenient aerosol spray cans or mixable powder form can be purchased online at HVAC Maintenance & Supplies. Allow the coil to soak for 3-5 minutes then flush out with a garden hose. Be sure the water pressure is not so high that it damages the coil fins. A coil fin tool, also available online can be used to straighten the fins. Repeat this process until the water starts to flush out relatively clear. Safety glasses and rubber gloves should be worn when using coil cleaning chemicals.
If your air conditioner is a portable window type you can carefully remove the units outer casing, apply coil cleaner to both evaporator and condenser coils then flush with water. Most dirt will build up on the inside of the condenser coil that can not be seen with out removing the units outer casing. These tips may not resolve all your air conditioning problems but I can tell you that as a service technician myself these are some of the most common problems I have encountered.
Information provided by Terry Manlick with HVAC Maintenance & Supplies. Other maintenance articles as well as hvac maintenance products such as filters, v-belts, humidifier filters and coil cleaners can be found online at www.mainsupplies.com
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More commentsI'm working in a contractor company. I have a problem in the aircon unit we repair.The refrigerant compressor has high ampere after the cut-off time .you mean when he start..
how to know the motor compressor is loose compression
Can anyone help? Terry??? TYRich from Vegas: I have two Lennox units, one for upstairs Model 12ACB60 and one for downstairs Model 12ACB48. I came home from work to find the house warm and checked the thermostats to find them both at 76* but the house temp at 85*, I went to the unit outside and had my wife turn stat off then back on where I seen contactor pull in but no compressor. I checked breaker in garage was tripped, I reset it and it ran for about 15 min and while I was looking at upstairs unit the downstairs unit shut off w/ a hissing sound coming from it for several minutes. Not sure if it was some sort of pressure relief valve? I checked breaker for upstairs unit and it seems to be on and ok but no compressor on that one. I cleaned my Metal filters about 1 month ago so I dont think they are problem. I changed start/run CAPS in 2008 on 1 unit and 2005 on the other. Contactors contacts look ok. Im an elevator tech profession, so i have TS skills and try to do annual PM's to keep these things from happening. Which direction would u go from here? BTW, I have not done any PM's in 10 years to furnace unit/evaporator in attic besides change PC board last summer and fan blower on 1 unit. Thanks...can u send reply as well to richribera at gmail dot com TY agaian.
Rich from Vegas...concerning those two AC Lennox units. I changed the run/start caps as well as burnished the contacts on the 24vdc contactors and one started up and is still running fine after 12+ hrs...the other shut off after 15 minutes...here was the symptoms. Once unit started, over the next 15 minutes the big pipe (suction) kept getting colder and colder while little pipe was warm...after 15-20 minutes I noticed a different sound coming from my outside compressor unit...I looked at the heat exchange unit where the pipes enter the duct which goes to Evaporator and they were NOT frozen...cold but NOT frozen, however the little pipe was extremely HOT...couldnt touch it for more than 1/2 a second w/out burning your hand... what does this mean? Is it compressor issue? Blockage in TXV, low on Freon or something else?Thanks in advanceChemically clean the out door / Condenser coil. Is the out door / Condenser fan running at the proper speed? What is your suction and head pressure.Terry
changed filter and checked drain vent but ac keep freezing so i have to turn it off and wait till all the ice is gone b4 i turn it back on can anyone give me a hint on what to do?Clean evaporator coil. Check freon level.
hello window unit on low fan or low air does not work at all,on med speed air or fan grrrror humming if i physicaly turn fan on med possision all systems go air perfect brrrrr.
My HVAC unit starts to blow cold air and then stopd after 3 mins. Don't know what to check.Any advice would be more than welcome!!
my unit is short cycling?
My ac unit i think took a surge from a storm. A local handy man stoped by and took a look said it was the capacitor on the blower motor. which we replaced for 10 $ however still comes on and blows cold for a while and then kicks off. But then comes back on and blows cold the on time is getting longer but I can tell something is not right cause it pulls the lights dimmer in the house when it kicks on.May need a hard start added to your compressor.
Hi, i have a trouble in one of my AC the high side getting a low temperature . my gauge manifold reading in high side is only 90psi in low side is 62 psi when i add freon the motor turns loose and late sunction..can you about this ?
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