Here is a recent email I received this weekend:
“I have a repair question for you whenever you got time. I have a 4 ton R22 condenser with a good tested capacitor of 40uf for compressor. However, when thermostat calls for cooling the contactor engages but compressor doesn’t start, I do have good voltage of 240 across t1 and t2 and the start leg coming from capacitor to ground is 120v. However, no amps. I tested each leg to ground and nothing (no grounding). This is the original size of capacitor for the compressor. The compressor was working a week ago but a day ago stop working . Would you call this a bad compressor?”
First note that the technician needs to check the resistance across the leads to the compressor. It may not be shorted to ground but it may just be internally shorted. To test the compressor, I would first check the resistance across the leads. Common to Run (r1), Common to Start (r2) then Start to Run (r3). What you should see is r1 + r2 = r3. Also, check for continuity across the windings this way for any open winding. Make sure the power is off and the leads are disconnected from anything when you do this. If you find an open winding or the resistance isn’t adding up right, then your compressor may be bad. Also do you have 120V on all 4 legs (top and bottom) of the contactor when engaged?
My hunch is that the compressor has an internal short and there is no continuity on one of the leads.
Have you had an air conditioning company replace a capacitor recently? Have you ever wondered ‘how can I tell if the air conditioning capacitor really needed to be replaced?’ This video will show you one way to visibly tell if an ac capacitor has failed. This is not always the case, but if you do see your capacitor looking like this then it definitely has failed. Alexander Heating and Air Conditioning knows air conditioning troubleshooting and replacing a capacitor is always a common question from the homeowner. Warning: hvac capacitors hold an electric charge equal to the high voltage connected to it and can be a severe shock hazard. Do not touch the capacitor. So next time you are wondering what are some of the bad ac capacitor symptoms, you now have one of the most common symptoms to check.
Visit our web site at http://www.alexhvac.com
When they are dirty or every 3 months which ever comes first.
I see so many homes with clogged air filters when I arrive. This can wreck havoc on your air conditioner and heater as well as your indoor air quality. Dirty filters can lead to frozen pipes, dirty blower fans, and burned out blower fan motors.
Risking a $700 fan motor replacement bill over a $6 filter is ridiculous. Buy a box of filters from your local supply store and keep them in your closet. Then change those filters when they look gray or every 3 months. save yourself some agony and money.
Pets and kids will clog your filter faster than a home without pets and kids? Think about it, pets have twice as many legs and move them twice as fast as an adult human. Therefore they will kick up more dust and other airborne particles much easier than otherwise. The airborne particles collect on your filters and halt the air flow to your air conditioner or furnace. This causes the fan motor to work harder and possibly shorten the life of the fan motor.
Do not pay attention to the filter life displayed on the filter packaging. Unless the filter is thicker, such as a 2″ thick filter, most filters only last around a month in the average household. Even if the filter says a 3 month filter, it just means it is a more dense filter that collects more airborne particles. And as was just pointed out, the more airborne particles collected, the more frequent you will need to replace the filter to prevent the loss of air flow.
The problem with the typical central home AC is you have to cool the entire home it’s like having just one switch that turns on all the lights.
This was ok 20 years ago when we were paying like $0.004 per Kilowatthr…But now in Fresno Ca Pacific Gas And Electric is charging over $1 per peak KWH!!
Mini split AC systems and so called Ductless units are being promoted but they cost 3 to 4 times as much as a cenrtal system per ton.
It is way better to use smaller packaged air conditioners AKA window ACs but to mount them outside of a window so you do not see or hear them.
Using soud damping material in flexable ducts or ridgid ducting will allow these not to be heard from inside a room…this is perfect to cool a bedroom on hot summer nights to a cool 75F for about $1 a night
When so mounted there is a clear advatage as you just turn on the zone you are in. Window ACs can be bought from discount Ebay seller for a low as $200 per ton of cooling…or 12,000 BTU
The best part of using this approach is:
1- You never have to replace your old central AC for over $10,000 as is a typical high SEER AC system upgrade
2- If a single smaller zone AC unit fails it can be replaced for about $200 and you do not to hire a HVAC contractor to put the new on in.
3- On those rare super hot day ( like we just had at 112F in Tucson) you can turn on the old central AC until the smaller zone units can take on the cooling load.
4- If you have a typical solar power system it should be able to power 3 to 4 smaller zone ACs . The typical home solar power system is not able to run a 4 ton central AC unit
You can solve that problem with zone damper system by Honeywell. installing dampers at the air handler for each zone then running a thermostat to each zone will improve the dynamic cooling requirements of each zone and is a lot less expensive than buying and retrofitting all those window units. Visit us at www.raleighheatingandairservice.com/articles to learn more.
Interesting DIY Air Conditioners
I’m trying to decide what smart thermostat to get for a new system, and the Nest and the ecobee are the most appealing products I’ve found so far. Most of the problems I’ve read about with Nest systems are in cases where there’s no C wire providing power and so the battery runs down; however, in a new system I can just make sure I do run a C wire so I shouldn’t have any of that type of problem.
So what other considerations should lead me one way or the other?
WHOA! Just because you run a C wire doesn’t mean the thermostat is capable of using that C wire. Note that the batteries (if only two) are only about 3 volts. The R/C combo is 24 volts and may fry your thermostat. The function of the thermostat is just to turn on and off a switch at the appropriate temperature. So all the bells and whistles are the sales tools to get you to buy their brand. My recommendation is a good quality programmable thermostat so you can adjust temperature while at work or at night and save a few bucks each month. If you’re a tech gadget kinda guy, like me, then the Nest is pretty cool from a gadget perspective. The main function is no different than the old mercury switches of long ago; It opens and closes a circuit. – Frank Alexander
Capacitor Failure Symptoms are sometime harder to identify without the right tools and expertise. Capacitors can be found in several different sizes and shapes. There may be one or multiple capacitors included in your ac with regards to the design. While the most popular capacitors are the types found on circuit boards, the ones most associated with air conditioning will be the bigger capacitors that assist start and run your motors. There are several motors present in an conditioner and heater systems:
- Compressor Motor Run Capacitor: Here is the most popular capacitor that fails. Most of the time these are duel capacitors, which means that there are 2 capacitors built into one. A duel capacitor will have three terminals on the top where a single capacitor will simply have two terminals on top.
- Outside Fan Motor Run Capacitor: That is the smaller capacitor found with or part of the Compressor Motor Capacitor. It helps start and run the outside fan that blows air through the outside coils.
- Indoor Blower Motor Run Capacitor: Similar to the outdoor fan motor capacitor, it is a small, single (two terminals) capacitor that will help start and run the indoor blower motor.
- Start Capacitor: Some models include an auxiliary start capacitor that helps jump start the motors. Most are found on the compressor. These are less common.
When capacitors go south, they either go out entirely or they decline in strength. The decline is measured in the “capacitance” units called micro farads. When the capacitors are produced, they are labeled with their specifications capacitance and a range +/- from the design capacitance. This range is the allowable operating range, usually labeled in a percentage range, for the capacitor. If the capacitor starts to fail, the capacitance measured will be outside of the labeled range. Sometimes these are difficult to find any symptoms unless you have the proper tools. Warning, there is a risk of severe shock, so do not try this at home.
If a capacitor goes out completely, or is severely out of its operating range, it may prevent the motor affiliated with it from running completely. If the compressor motor is not working, then the air conditioner will not cool. If the outside fan is not working the compressor may cause problems and will short cycle or cease working. If the indoor fan stops, you’ll find that there is no air blowing through the vents.
For Quick, Honest and Affordable Service, call
Alexander Heating and Air Conditioning
Raleigh Air Conditioner Repair
Holly Springs Air Conditioner Repair