Posted: 5/28/2009 8:28:54 AM EDT
| Where to they usually put the temp sensor that causes it to cycle? I wanna insualte it so the a/c part is on when I have it on. This is an older A/C unit, so I dont care about the wear and tear on it. |
| If you find the control knob that turns the temp up/down and follow the thin capillary tubing that comes out the back you should find it..... BUT if all you are trying to do is make it come on and stay on all you have to do is jumper over the thermostat and it will never shut off..... at least until the compressor croaks. You could take the 2 wires off of the control and wire it to a toggle switch and when you click it ON it will be ON and when you want it OFF just hit the switch..... if I understand your question correctly anyway. |
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Two problems here. First, the occasional cycling helps keep the evaporator from freezing up (the radiator-looking thing in the front of the unit), usually right behind the filter. The radiator-looking thing on the back of the unit (outside) is the condenser. You'll actually see ice building up on the evaporator. If you put the unit on it's coldest setting and it's full of Freon, then the cycling should be minimal.
Second is the problem with power outages. When the power flickers, even for a second, the unit delays the compressor from starting up to avoid building up too much head pressure. If the compressor loses power and then immediately re-starts, the pressure hasn't had a chance to bleed-down and is REALLY hard on the compressor. It's also unsafe to direct-wire, because if the unit freezes up or the freon runs too low, the low-pressure and overheat circuits are disabled and you could wind-up with a flaming wall.. |
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Quoted:
Two problems here. First, the occasional cycling helps keep the evaporator from freezing up (the radiator-looking thing in the front of the unit), usually right behind the filter. The radiator-looking thing on the back of the unit (outside) is the condenser. You'll actually see ice building up on the evaporator. If you put the unit on it's coldest setting and it's full of Freon, then the cycling should be minimal. Second is the problem with power outages. When the power flickers, even for a second, the unit delays the compressor from starting up to avoid building up too much head pressure. If the compressor loses power and then immediately re-starts, the pressure hasn't had a chance to bleed-down and is REALLY hard on the compressor. It's also unsafe to direct-wire, because if the unit freezes up or the freon runs too low, the low-pressure and overheat circuits are disabled and you could wind-up with a flaming wall.. I've been in the HVAC/Refr. business for 30 years now and my only reply to your "problems" are: Problem 1 BS A properly charged unit runs a 40-45F evaporator temperature and if I remember my science class correctly ice doesn't form until 32. IF it is low on charge it definitely will ice up, and a thermostat won't keep ice from forming or shut it off..... and on top of that, these older units were NOT equipped with low pressure controls to protect against leaks. Most older units don't even have pressure taps that you can put a set of guages on. As for the "overheat circuits and flaming wall" the only over temp/over amp device in these units are the compressor overload, It makes no difference at all whether it gets it voltage from a thermostat or a switch in it's operation. problem 2 BS Older window units like he has don't have ANY short cycle time delays built in. Most residential units, except high end models, don't have time delays either as they are built into the electronic thermostats instead. If the power flickers it doesn't matter either way whether the circuit is made through a thermostat or a toggle switch at all. Granted if this were one of the newer electronic board equipped model it would make a difference, but not with an older type like he describes. IF you are in the HVAC Service Business you probably ought to go back to school, and maybe pay attention this time. |
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Quoted:
Two problems here. First, the occasional cycling helps keep the evaporator from freezing up (the radiator-looking thing in the front of the unit), usually right behind the filter. The radiator-looking thing on the back of the unit (outside) is the condenser. You'll actually see ice building up on the evaporator. If you put the unit on it's coldest setting and it's full of Freon, then the cycling should be minimal. Second is the problem with power outages. When the power flickers, even for a second, the unit delays the compressor from starting up to avoid building up too much head pressure. If the compressor loses power and then immediately re-starts, the pressure hasn't had a chance to bleed-down and is REALLY hard on the compressor. It's also unsafe to direct-wire, because if the unit freezes up or the freon runs too low, the low-pressure and overheat circuits are disabled and you could wind-up with a flaming wall.. Listen to this man. They don't put a lower temp limit on it just to keep you from being comfortable. You may not end up with a flaming wall, but the freezing up is a definite possibility. I've seen it happen... |
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The issue isn't how the compressor comes on or off, it's whether it shuts off when the room gets cold.
I've seen, more than once, where a unit will NOT freeze when the temp stays at a reasonable temp, say 70+. But get the temp down lower, and the coils start to frost over, airflow is restricted, more ice, then you're looking at a solid block of ice over the coils. I've seen that happen in central air units, window-mount units, and the units with rooftop compressors. |