Trane compressor running backwards

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Baltimore, MD
My sister lives in Florida. She says it been very hot this year.
She has a two year old Trane a/c system.
The compressor will occasionally make a strange noise. She called the company that did the install and they told her occasionally the compressor is running backwards due to the power going off and back on very quickly.
They told her they can install a timer for $400 that might fix it.

Are they talking about a DOB timer like an ICM203?

Is there something else that might work better?

Thanks for your time!



The wife is still training me.
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Orlando, Florida
This is a two week old post so I’m not sure if it was fixed. The timer is normally performed by the thermostat. When the AC is turned off by the thermostat there is usually a 3 minute period before the thermostat powers up the compressor. This is to allow time for the head pressure to reduce, thus it prevent the compressor from running backwards.

It this a heat pump? What told her the compressor is running backwards? It might be in heat mode during the problem scenario.

If the thermostat runs on batteries it will not know that there was a power outage so it keeps the circuit closed (usually the yellow wire). Another fix is to install a WiFi thermostat. These require five wires because the c-wire must be connected to the thermostat. The Red wire is the 24 volts and the c wire is the return so the thermostat has power from the air handler where the transformer is. You lose power, so does the thermostat. On power up there will be a delay. Honeywell makes a nice unit and cost around $180-$200. Any DIYer should be able to install one.

Depending on the age of the home there may only be four wires to the thermostat. If the thermostat is near the air handler running another wire could be possible.

One last thing, some Trane units required a proprietary thermostat. A model number of the air handler and a picture of the thermostat will help.