My boiler heats up to 180 but I have no psi according to the gauge

Gauge could be defective. If not the altitude or as some call it pressure is caused and controlled by the cold water feed line that is attached to the boiler. Usually there is an automatic feed valve that is preset for your system so it does not over fill and cause too much pressure. Now the fill valve could also be bad so you will have to check things out before just adding water.