I have old Carrier condenser 5 ton 3 phase split unit. The Furnace is running and signal to start Ac good. I replaced the capacitor (single capacitor) and nothing started. I can manually start the unit at the contact switch. The compressor start but fan does not run. I wired the capacitor by power to one side and motor & Compressor on other. If correct how do I check the motor.
A three phase compressor does not use a capacitor! The fan can be single phase however even though the supply is 3 phase. Call an HVAC tech before you cost yourself more than you are trying to save!
Your 3 phase unit should not have a capacitor. I'm guessing it's single phase. If it's a single capacitor than the compressor should not be going to it also. To test the motor, common to start plus common to run should equal the ohms you get between start and run. For instance, 1.2 ohms+ 2.2 ohms= 3.4 ohms. Follow the wiring diagram on the inside of the door, send model number!!
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SOURCE: home unit 3 ton won't run
The small capacitor is for the fan motor the other for thecompresor .You can try conecting a booster (or hot start) in paralel to the comp.capacitor .If this doesnt work you have to replace the compresor.
SOURCE: COMPRESSOR NOT RUNNING, HOT
The high side/low side pressure equalization you describe is normal for a compressor sitting idle.
If you have an ohm meter you can check the compressor windings for opens and shorts. If your compressor is 3 phase as you state (this would be very unusual for a residential unit) you should have continuity across all 3 phases and no continuity to ground. Take the compressor out of the circuit before you check.
If the compressor does have crankcase heat, it should have been left on for at least 24 hours before starting the unit. Another cause for failure could be overcharging which could have resulted in refrigerant slugging back to the compressor.
Does the unit have any low or high pressure control safeties? If so, check them too - some have resets. You said the condenser fan ran so it's not likely the breaker blew, but check anyway and also check to make sure you have available power on all 3 phases.
SOURCE: My ac fan went out on a carrier ac unit. Need wiring help
use a seperate capicitor for the fan only pick up 1 leg of power from common side of the compressor cap and the other from the contactor or the board in a heat pump situation
SOURCE: I had to change the compressor of my 2 ton
I would say control board. Get on Samsung web site and go to technical support and get there 800 number. I have called several times and they can walk you thru it. Just have your m They model number handy. They can also tell you wether you need a service tech or not. Be sure to ask for free estimate. Rus
SOURCE: carrier 48NMX042 IFM wont stop, condenser fan motor and compressor wont run
Ok first thing is it sounds like a wiring problem. So first step is to make sure the thermostat is properly connected. Which... the main thing here is there needs to be 24v dc power coming from your control board (transformer) going to the thermostat..generally that is the red wire. All the thermostat does is connect that "red" wire (power) to one of the other wires to complete a circuit. So make sure you have 24 volts... (generally about .5amps) . if you have power than switch thermostat to fan only should energize the green wire only. then switch to ac and move temp low enough that the ac should turn on and that should energize the yellow wire. for sure one of those wires is incorrect now or the fan wouldn't be on OR THE THERMOSTAT IS NOT CONNECTING THEM AND IT IS BAD. Now about the compressor and fan.... those same wires run out to the compressor unit... ok the yellow for ac.. greeen does not go to compressor unit that is for fan only (vent).. red carries the same 24 volts... one difference here is that most carrier units only have the one transformer....so you run the red wire is the +pos 24 volt..and then a "common " wire is needed which is the Ground or neg... that wire on a carrier is brown usually but could be different depending installer. The orange wire goes to the pump reversing valve it is always energized when on ac mode...when heater is on in the winter it is heat pump and is not energized so just connect the orange and yellow together... tell me more specifics if this doesn't help and i'm sure I can help you... thanks Chuck
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