HVAC not "engaging"


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Old 03-20-24, 07:19 AM
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HVAC not "engaging"

I just replaced batteries on a White Rodgers thermostat as they had died. After replacing heat pump will not start even though thermostat now has heat/cool settings display. Anyone have any idea why this is happening??



 

Last edited by PJmax; 03-20-24 at 06:38 PM. Reason: resized pics
  #2  
Old 03-20-24, 07:23 AM
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Start by checking the simple stuff.
Try a different set of batteries.
Make sure both switches are fully in the positions you want.
Try moving the switches to a different position and back to where you want.
Look closely at the wire connections inside the thermostat. Are they all in position and tight? Are any wires touching and shorting out?
Check the circuit breaker for both the inside and outside units are not tripped.
Check the service disconnect for both the in and outside units. Sometimes they have fuses that might have blown.
 
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Old 03-20-24, 04:05 PM
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Looks to me like the right switch is set to off. For heat I think you need to slide it one click to the right.
 
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Old 03-20-24, 06:41 PM
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That stat is wired for FAN ON operation which means the fan should be running right now.
 
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Old 03-21-24, 02:41 PM
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Low amp fuse

There is a low amp fuse, usually located near the furnace\air handler that can blow very easily. It's usually 1 or 2 amps. If it's blown the thermstat is on, but can't signal the unit. Look for it and change it if necessary.
 
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Old 03-21-24, 04:01 PM
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Welcome to the forums.

Although there may be a protection fuse it's usually 3-4A and changing the batteries in the thermostat shouldn't cause it to blow.
 
 

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