Removed lid to steamer ,took all three probes out and replaced them with new ones. turned unit on and unit filled and contactors pulled in. unit heated for about 3 min then cut out with timer on. llco. satisfied. traced to pressure valve not closing. adjusted to proper setting and unit stayed steaming. checked timer per Sean kitchen manager. he said wasn't timing down. when contactors pulled out no power to timer. timer timed down and buzzed now. unit is operational job complete.