A/C slow respond to thermostat setting

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  #1  
Old 08-11-00, 07:26 AM
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I noticed today that my A/C came on for a brief second and went off. I tried to set the thermostat at a lower temperature, and it took a 5-10 min before the A/C would come on. So I turned it back on at a higher temperature, and it took about 5-10 min. before the A/C would be off. I think there is something called a RELAY (??) which would transmit the temperature reading from thermostat to A/C. Do I need to call the technician to replace it? Thanks for any replay.
 
  #2  
Old 08-11-00, 09:54 AM
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I'm not an HVAC man, but our heatpump has a built-in 5-minute delay, and I think that it is normal. Don't worry about it, unless it stops doing its thing. Good Luck!
 
  #3  
Old 08-11-00, 12:08 PM
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quote:<HR>Originally posted by OldGuy:
I'm not an HVAC man, but our heatpump has a built-in 5-minute delay, and I think that it is normal. Don't worry about it, unless it stops doing its thing. Good Luck!<HR>


Thank you. How long would the delay device last? Ours is about 10 years old.
 
  #4  
Old 08-12-00, 12:18 PM
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If it's as new as 10 years old, the time delay is as likely as not to be a solid-state circuit attached to the fan relay or part of the main system controls in the air handler. Short of an electrical surge, it should last as long as any other solid-state device.

There are a couple of older technologys for providing a time delay, but they are all fairly rugged as well.
 
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Old 08-12-00, 02:43 PM
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Curious????

Why would his unit come on for a few seconds and shut off? The time delay only to keep it from starting too quickly in between , right? to protect the compressor? What would make it shut down as soon as it comes on, without moving the t.stat. Possibly the compressor overheating and kicking out on the overload?
 
  #6  
Old 08-12-00, 09:44 PM
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Hi Everybody:

First- the Time Delay. Many units have a delay timer to prevent compressor short cycling. It's a Delay on Break type of timer. Translation- when the t-stat initially calls for the compressor to run, the timer closes and allows it to start. When the t-stat is satisfied and shuts off the compressor, the time delay begins. If the t-stat again calls for the compressor to run within the time delay period, [ usually 5 minutes] the compressor will not start until the REMAINDER of the timing period elapses. If the thermostat calls after the delay period has timed out, the compressor starts. The delay period begins after the thermostat is satisfied and BREAKS the circuit. If you ever have to replace one of these timers, be sure to get the right kind. You would not want to use a Delay on Make timer.
Second- it sounds like angelt might have a digital thermostat. They will not respond to setpoint changes right away like an electomechanical type thermostat will. If the quick on/off only happened once. I wouldn't worry about it. If it continues, it should be looked into. Thanks. John.
 
 

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