If your air conditioner was not keeping your house cool during the recent heat wave or if your summer electric bills are higher than your neighborsâ, your problem might be an overcharged air conditionerâone that has too much refrigerant.
If an air conditioner is undercharged with refrigerant, it will not perform well, so contractors at installation sometimes will overcharge a system to save time. To get the pressure just right involves testing the system for temperature and pressure differential between the outgoing and incoming refrigerant lines at the compressor. This test can be done only when the AC is running, and the test takes at least fifteen to twenty minutes to complete. To save time, some contractors will guess at the amount of refrigerant to charge the system with, and they will add a little extra to be sure the system is not undercharged.
If your air conditioner is not keeping up on days when temperatures are in the mid-90s, overcharging may be your problem. The most reliable check for this is temperature and pressure gauges on the high and low sides of the system, but since most people donât have these, feeling the outlet tube from the condenser unit is a good indicator. The outlet tube is the one that is not insulated. After the unit has been operating for fifteen to twenty minutes on a hot day, that tube should be hot, but not too hot. By that I mean, if you can hold on to it and not burn your hand, it is all right. If you can not leave your hand on the tube, it is too hotâprobably over 150°. This is a pretty good indicator that your system might be overcharged. The reason for this is that an overcharge of refrigerant will cause the pressure in the system to increase and with it the high side temperature. This will cause the system to operate less efficiently than it was designed to run and will cost you more to operate. It is much like driving a car that is out of tune; it will use more gas.
While you are checking the outlet tube for heat, look at the inlet (suction) tube. This is the one that is insulated. The insulation is there to keep this tube from sweating because it is bringing the cold refrigerant back from the evaporator and will attract condensation from the air just like a cold drink will. If this insulation does not extend all the way up to the metal condenser unit box, you should add some foam insulation. You should also check the other end of this tube, where it goes into the furnace. If the insulation does not extend all the way to the hole where the tube goes into the furnace, this tube will sweat and drip water onto your furnace. Wrap some foam insulation over the bare tube.
If you suspect your air conditioner is not efficiently cooling your house and you find that the outlet tube from the condenser unit is very hot, you should have a service man check the pressures on your system and adjust the refrigerant.
Urban legend
Sun City has one of the most efficient grapevines of any community in which I have lived. Unfortunately, it propagates bad information as well as good information with no prejudice. The latest one is that if your cell phone battery is low, you can press *3370# and your cell phone will restart with its reserve power and give you a 50% increase in battery power, allowing you to complete a call. This reserve will get charged the next time you charge your phone. This sounds like a nice feature that you should store with your cell phone in case you need it. Donât bother; it doesnât work.
This feature is a misunderstanding of a Nokia code function for Half Rate Codec, which provides 30% more talk time on a battery charge at the expense of lower sound quality. However, this option is enabled by pressing *#4720#. The *3370# actually enables Enhanced Full Rate Codec, which provides the best sound quality but at the expense of shorter battery life. These codes only work on Nokia phones.
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