My apartment has five Marley C Model TA2ANWC, double thermostat, 22 amps 120-277 baseboard heaters. All are wired with 10-2 AWG.

One double circuit breaker is marked with two 60s and the three units work fine.

The other double circuit breaker is marked with two 50s and operates the other two baseboard heaters... BARELY!! A wall thermometer only reads 70 degrees when resting on the unit 10 minutes compared to 120 degrees of the other heaters in two minutes.

Common sense tells me the circuit breaker is the culprit. I was taught how to replace breakers but never taught about the numbers. My out of town landlord is dragging his feet to correct the issue and we have single digit wind chill temps. I need to get the two units working.

First you need to check the ofending circuit breakers to see if they are really bad. You will need a electric meter/tester. When activated each leg of the 220 volt breaker should show 120 volts or there abouts. When jumped across the two terminals it should read 220/240 volts or there abouts.

From your description the baseboard heaters might be operating on 120 volts so I am confused as to the exact wiring and without being there this is the best info I can give.

If the heaters that are having a problem are heating at all it could be the circuit lost one leg of the 220 volts. It is also possible that the thermostat or limit control could be defective.

The owner of your dwelling unit is responsible for repairs especially heat so if he does not want to fix it call a repair person pay the bill and deduct it off your next rent payment.