Hi everyone

I've been a lurker on these forums and this is my first post. So I picked up an older Isomac Millenium that wasn't heating up for a good price. Took it to a repair shop and had the heating element replaced. I was told it was tested and working perfectly. Brought it home and turned it on, left it to heat up. Came back and to my surprise, it had made a giant mess! Big puddle of water underneath. But it heat up fine. So I opened it up and saw that one of the tubes that goes from the reservoir to the boiler had literary melted! Not sure if it's an intake or exhaust. Any ideas what could cause this? I'm gonna take it back to the shop but just though posting this here might give me some insights before he charges me for an arm and a leg for something that could be a simple fix.

Probably would be good to see some photos.

I'll take some photos later but basically the side of the tube that's facing the boiler is like burnt. It's black and the part closest to it has burnt off and melted completely, severing the tube