Arrived at location on 4/23/21 to service Cleveland Steamer 394. Spoke to the chef. He said that there was a bang and a flame shot out the back. Verified delayed ignition. Turned on. Filled ok. There was a bang and a flame shot out the flue. Intermittent spark. Getting 24v to module. Ignitor was burnt. Need new ignitor and module. Will obtain and return. Prices given to customer. Installed parts. Turned on. Filled and heated. Steams ok. Did not bang or make unusual noises. Back in service.