I have an air conditioner that is probably 15 years old now. The problem is when I turn it on after it has been off for a long period of time (several hours) it takes a long time for the outdoor unit (compressor?) to start running. The outdoor unit has a large fan in the middle with cooling coils around the perimeter and cooling fins. It had been running just fine up until three summers ago. Two winters ago, my heater went out and I had it replaced. The following summer (last summer) I went to turn on the air conditioner for the first time and it took so long (30 minutes) to come on that I thought it was broken or not wired up or a fuse blew. I checked all the obvious things like the set temp was below the room temp. The wall unit has a red light that glows when either the heater or air conditioner unit is operating. I figured the heating & cooling guys forgot to hook something up. Having a bit of electrical know-how, I went and checked the outside fuses and other things and could see the outdoor unit had voltage going to the outdoor unit.

Just today, first time turning on the air conditioner for the year and same behavior. Here is the interesting thing though. Once the unit kicks on, it cycles normally. I can hear a small click (relay closing) on the inside thermostat unit each time the termostat cycles on/off. I can then hear the outside unit kick on within a few seconds of hearing that click (normal).how much does a small hvac unit cost On mild days, I turn the air conditioner off and it may be off for a day or two but then turning it on for the first time, I can hear the thermostat click but the outdoor unit takes 30 minutes on average to come on for the first time.capacitor in ac circuit I don't have a schematic for the unit but I can't imagine an outdoor relay taking that long to engage if it's a relay problem. energy efficient ac and heating units

Also the outdoor unit has this blanket around the motor. I tried removing it when this problem first began but the unit seems sealed up. The guys that put in my new furnace insist they did nothing that would have caused this but want $85 to come look at it. Anyone recognize this behavior? There is probably an old capacitor in the electronics which dried out over the time and now takes a long time to gain the necessary power load. If you are familiar with electronics you can check yourself for capacitors which looks bloated or otherwise funny and replace them. I know that when a capacitor fails to start up it can cause the compressor to overheat and it will simply be slow to start. Therefore switch off the power, and after it gets cool, replace your capacitor for proper operation. And if you are in a hurry, you could pour some fresh water to the compressor to cool it. If your outside unit isnt cycling on and you have line voltage coming in to L1 and L2 first thing I would check is the contactor you say it does come on.

If its cooling when it comes on the your condensor fan and compressor are working fine.Delay Timers and the Air Conditioner Condenser - Air Conditioners are big HVAC refrigerators. Air Conditioners and Heat Pumps use the HVAC refrigeration cycle to transfer heat from a place where it is not wanted (inside absorbing heat with the evaporator coil) to a place that makes no difference (outside using the condensing unit)(in the cooling cycle). The heart of any HVAC air conditioning, heat pump, or refrigeration system is the compressor which pumps the refrigerant through the HVAC air conditioning system.When the refrigerant leaves the compressor it is compressed and therefore a higher pressure than it was before it entered the compressor inside the condensing unit. This pressure remains constant (give or take under certain conditions) until it passes through the metering device where the pressure and temperature are reduced. This low pressure remains constant (again give or take under certain conditions) until it again reaches the compressor inside the condensing unit and is compressed again.

Pressure Equalization in the Condenser When you turn the air conditioner condensing unit off these pressures equalize within five minutes. The equalized pressure is often referred to as static pressure to HVAC professionals. The high side pressure on a hot day can be as high as 300 P.S.I. in some systems. If your HVAC system is not equipped with a delay timer and you turn the system on within five minutes of turning it off, the compressor inside the condenser must start against that higher pressure. That is not good for the compressor and could possibly damage it.ProblemThe HVAC air conditioner condensing unit compressor should not be started unless the air conditioning or heat pump system is at the static pressure. I have responded to calls where the air conditioner or heat pump condensing unit was not equipped with a delay timer and the air conditioning or heat pump condensing unit was inadvertently started before the pressures were allowed to become static. Often the compressor inside the condenser is locked up, the run capacitor is shot, a fuse is blown, the compressor is damaged mechanically or electrically beyond repair, or a combination of any of these things mentioned.

HVAC Condensing Units and Compressor Mechanics – Delay Timers and the Air Conditioner CondenserIf the homeowner is lucky, the only thing wrong is the capacitor or fuse. The capacitor for your compressor can be replaced for a minimal cost compared to replacing a compressor. If the compressor is locked up there is a chance that it can be unlocked (note the word chance). A hard start kit and a good rap with a hammer can sometimes do the trick. If this doesn’t unlock the compressor then you will have to replace the compressor or the air conditioning or heat pump condensing unit. It is often in the homeowners best interest to replace the condensing unit. Before this happens to you, call the company you often deal with to maintain and repair your HVAC system(s). Ask to speak with the HVAC service manager or HVAC technician that has worked on your HVAC equipment. Ask them if your condensing unit is equipped with a delay timer. They should be more than happy to answer your question…………and if they are not sure ……check to see if the condensing unit is equipped with a delay timer.