Ill try to explain. There was a small 240v blueline subpanel feeding the kitchen circuits. This sub panel was fed from a 40 amp 2 pole breaker in the main panel. The kitchen splits are fed from the blueline sub panel with 2pole 15 amp breakers. The kitchen receptacles have a black and a red and the tab was not broken, they worked for all of their devices.If the tab is not broken you couldn't possibly have 240V split receptacle. One leg or the other is not making it to the receptacle. There is either a joint not made up somewhere between the breaker and the receptacle, a break in the wire, or you have matched the wrong breaker to that receptacle.
No I thought this too but its impossible to use a 2 pole breaker and get 120V.I've never worked with a blueline panel but I googled some pictures of the breakers. They look like a half space breaker where a 2 pole breaker could be plugged into a single bus stab like a federal stablok. Is this the case?
Op didn’t touch the blue line panel though. He came in and swapped the main panel. I’d put good money on that blue line panel has never had 240 volts. As far as we know the only thing in this circuit that’s changed is the breaker feeding the sub panel so almost certainly that’s where the problem was.One of the breakers of the split in the blue line panel was tripped, but it didn’t show, the breaker looked to be on but wasn’t. Common problem with those old breakers.