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Definition of one ton of cooling capacity (C) Carson Dunlop Associates & InspectApedia.comAir Conditioner / Heat Pump Starts after Cooling Off FAQs

Why does an air conditioner or heat pump system run only if first turned off for half an hour or more, presumably to "cool down" the motor or other parts?

This article forms part of our series on how to diagnose and correct air conditioning problems like lost or reduced air conditioner cooling capacity, reduced or no cool air flow, reduced or no actual lowering of the air temperature, or an air conditioner that won't start.

Page top: this shade built over an outdoor compressor/condenser unit may be too close to the unit's top, reducing air flow and contributing to condenser unit overheating.

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Air Conditioner / Heat Pump Won't Start When Hot FAQs

These reader comments, questions and answers about diagnosing and fixing an A/C or heat pump unit that won't run or won't start unless the system is switched off for a "rest period" (allowing motors or other parts to cool down) were posted originally

at AIR CONDITIONER WON'T START - home; be sure to review that article.

Air Conditioner or Heat Pump Works After Power is Turned Off for a Rest Period

Trane Heat Pump works for a while after we turn off power and let it rest for an hour

We have a trane R22 heat pump and the blower fan (internal) is acting up. I shut the power (three breakers) to the it and let it rest for about an hour.

Then powered it up and the blower will start when I turn the thermostat from "auto" to "fan on".

The compressor will turn on when I turn it to cool.

However, I don't believe the blower is fully operating as I get marginal airflow.

After an hour or so, the blower fan continues to operate but at a very minimal speed.

I was going to change the fan blower start capacitor but am now suspecting the blower motor too as I don't think the fan should slow down so significantly over time

Would a bad capacitor do this or is both the capacitor and blower motor bad? On 2016-06-01 by JJC

Reply by (mod) - I suspect a bad motor starting capacitor

Your description sounds as if the indoor air handler blower fan motor is overheating and then failing. That could be a bad or failing motor.

For example a bad bearing or a damaged motor winding might let a cool motor (it's been swithed off for an hour or more) re-start but then as the motor heats up the motor winding opens up or a bearing gets hot and begins to bind, slowing the motor.

Replacing the motor starting capacitor is a low cost thing that many HVAC service technicians would try first.

But most likely you need a new blower motor.

See our diagnosis and repair advice

at BLOWER FAN WONT START 

 

Why did my heat pump start working after I turned the breaker off, waited, then turned it back on?

My heat pump has not kicked on the last few weekends although the thermostat showed heat. A friend said turn the main breaker to off, wait 20 min. Turned it to on and approx. 5 min later it started.

Why was that? On 2016-04-04 by Trade

Diagnostic Guesses by (mod) -

Two guesses:

1. you reset the control board and maybe cleared an error condition

2. the compressor was unable to start against high head pressure that relaxed during its time off

See also these HOT WEATHER IMPACT on A/C or HEAT PUMP FAQs

My air conditioner stops working unless I turn it off for 45 minutes

What do I do, my kids are hot over here. My air just stopped working my fan on the unit is working but on my thermostat says low what do I do? I already checked breakers and they're all on.

Before when I turned off the system for 45 minutes or so then turned it back on the air conditioner started up again. - On 2016-06-22 by brandg

Reply by mod: turn it off for 45 minutes, try again, but call for repair

If the outside compressor/condenser is not working or if the system runs but there was a refrigerant leak that lost all or most of the refrigerant, then the system won't cool.

Turn everything off for 45 minutes. Then try once more.

If the outside unit runs and inside blows cool air, repair is still needed but you may get some cooling.

Else use some portable fans to cool things a bit and leave the system off while you wait for your service technician. O

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