07-23-2016, 04:44 PM
A capacitor can lose strength (capacitance) although they typically just fail. A bad capacitor can prevent a compressor from starting. A bad fan capacitor can result in higher amperage usage which can cause excess heat.
My Dometic AC units use a dual capacitor which is 2 microfarads / 20 microfarads. This dual capacitor has three sets of connections HERM, FAN and COM. The HERM connects t the compressor, the FAN to the condenser fan motor and the COM to the contactor and provides power to the capacitor. On mine, the brown wire goes to one side of the FAN connector, the Large Red wire and the small red wire to the HERM and the Big Yellow wire, Cream wire and small white wire to the COM. NOTE: a charged capacitor can get your attention (shock you) if you touch the wrong terminals. There are ways to test a capacitor but you must have a multi meter that has a setting for MFD and an adequate test range. My Craftsman Professional model 73756 does but most of my others don't. Remove the leads, attach one lead to the Fan connector and one to the COM connector and is should read at least 2 micro farads. Then test between the COM and the HERM and it should read at least 20 micro farads. It is possible that you have two separate capacitors but mine has a single dual capacitor and that is what the wiring diagram shows.
My Dometic AC units use a dual capacitor which is 2 microfarads / 20 microfarads. This dual capacitor has three sets of connections HERM, FAN and COM. The HERM connects t the compressor, the FAN to the condenser fan motor and the COM to the contactor and provides power to the capacitor. On mine, the brown wire goes to one side of the FAN connector, the Large Red wire and the small red wire to the HERM and the Big Yellow wire, Cream wire and small white wire to the COM. NOTE: a charged capacitor can get your attention (shock you) if you touch the wrong terminals. There are ways to test a capacitor but you must have a multi meter that has a setting for MFD and an adequate test range. My Craftsman Professional model 73756 does but most of my others don't. Remove the leads, attach one lead to the Fan connector and one to the COM connector and is should read at least 2 micro farads. Then test between the COM and the HERM and it should read at least 20 micro farads. It is possible that you have two separate capacitors but mine has a single dual capacitor and that is what the wiring diagram shows.