Keeps tripping breaker when running ac

What was the voltage that you measured? Are the units 220 volt or 120 volt. Units that size are usually fed by 220 volts. What is the current rateing of the circuit breakers? Are they a double breaker with a handeling capacity of 20 amps or are they 15 amps.

You didn't mention if they ever worked? Are you feeding 120 volts or 220 volts to the two units?

Good luck,

Marty

Few reasons, Low voltage coming in, due to long , undersized extension cord, or low power from where plugged in. If it runs ok on fan only, then "moans" and pops breaker when set for cool, it may be a bad capacitor to compressor, if all voltage etc checked out good. A weak breaker may also be cause but not usually.

Sounds like a bad contactor. The contactor will be near the compressor on the roof.

Make sure the condensor fan is blowing through the condensor on the roof. It sounds like the compressor is fighting high head pressures after running a bit.. After so many attepts, or if it suceeds in operating the load trips the circuit breaker.. Make sure the condensor is clean and air is passes through it from the fan. Just for clarifiication the condensor is the coil that gets hot and the evaporator is the coil yat create the cold air. Good Luck, and if you will, let me know how it turns out. Good Luck. Ned

CHECK FOR ELECTRICAL POWER @ l1 CONNECTION,IF YOU HAVE NO POWER CHCK THE FUSE,AND INSURE THE THERMOSTAT IS SET FOR COOLING OPERATION. IF THE UNIT HAS LEAKED FREON, A LOW PRESSURE SWITCH HAS OPENED, PREVENTING THE UNIT FROM OPERATING TO PREVENT DAMAGE TO THE COMPRESSOR. DO YOU HAVE A MANIFOLD GAUGE, AND ARE YOU CERTIFIED TO WORK WITH REFRIGERANTS? IF YOU ARE IN COMPLIANCE,HAVE TOOLS AND TEST EQUIPMENT WE CAN PROCEED FURTHER.

check the condensor fan in the rooof unit. It's the fan blowing on the cpil on the roof.. If it failed, the head preasures can becme excessive andwork the compressor hard causing the breaker to trip. Let me know and good luck, Ned_

seems that if it runs for 5 minutes there shouldnt be any shorted wires I would say your breaker needs replaced

Take a current reading on the compressor and the fan motors to see witch one is pulling the high current.

Check your CONTACTOR - the black "block" where all the line wires connect. Sometimes they stick. It's a cheap part, although make sure you take a pic of the contactor with all the wires attached BEFORE you take the wires out to get a replacement.

Ice on the coil is caused by 3 things; 1, low freon charge. 2, inadequate air flow across the coil, this can be a filter or dirty coil (I think you addressed these) or the fan isn't blowing enough air over the coil. 3, the unit is running continuously. A heat pump has another cause, that is something defective in the defrost system, like the sensor, reversing valve, control board or relay. If the breaker is tripping its because the compressor is over amping. There can be an obstruction blocking the fan or something like #2. Or the compressor is going out. If the breaker doesn't trip on other settings, like cool, but trips on heat, then I would look at the airflow.