Bryant A/C not working

My friend has a older bryant ac that is not working. First the capacitor was bad changed that and the starting capacitor since it was all corroded. Then I found the contactor was bad (lots of wear on the connecting plate) so we changed that out. I checked the low pressure switch and its seems to be good. I checked the compressor by olming the three terminals and adding the two terminals up our numbers were off by .4volts. I still can not get this unit to run any help or fresh ideas would help thank you.

 

If you take a small plastic or wooden object and press in on the contactor (with the power on), does the compressor come on? Have you checked to see if you have 24VAC at the low voltage (thin) wires on the contactor when the thermostat is calling for cooling? Have you checked to see that you have 240VAC across the two thick wires on one side of the contactor? You should have 240VAC on one side of the contactor, and either 0 or 240 on the other side depending whether the contactor is engaged (240VAC) or not (0).

If you have 240VAC present at the contactor but not 24VAC, one thing to check is the time delay relay. I have a 1992 Bryant AC unit and a few years after it was installed, the unit would intermittently not come on. It turned out the time delay relay had gone bad. I jumpered it and installed a digital programmable thermostat, as the digital thermostats have the equivalent of the time delay circuitry built into them. It keeps the compressor from turning on too soon after having turned off. Normally, there is a time delay of 5 minutes.

 

I have 26volts at the low voltage side of the contactor and 122volts on each leg of the contactor. When the thermostat is calling for cooling the contactor low voltage pulls in and I get power on the other side. There is a start relay is that the same as a time relay? How do you wire the unit without that in place there are three wires going into that relay one black, one blue, one yellow.

 

If you're measuring 26V at the low voltage side of the contactor, and the contactor is engaging, it's not the time delay relay, as that is in the low voltage control circuit. If the time delay relay wasn't working, you wouldn't get 26VAC at the contactor.