[Chillerman2010]

I have a 350 ton Carrier 19dk that is constantly alarming code 77 which is starter contacts failed to open. I traced the wiring from the aux. back to the I/O board and disconnected, but after reset, the 77 reappears. I've replaced the board, but it didn't make a difference. Also, the damned oil pump runs at random. Anyone seen this mystery before?

 

[milkyway]

sounds like it fail to transion., y delta starter.,

model
serial

more inifo.,.,

 

[heavymetaldad]

Did you run a controls test?

 

[Phisher]

The IOM says to check the (starter aux., starter contacts and the ICR relay). The ICR relay is part of the overload circuit. There is a normally closed contact on the ICR in parallel with the run aux. switch at the I/O board. Make sure your n/c contact has continuity thru it when de-energized. I can see the oil pump continuing to run as a safety if the controls don't see the starter opening.