Hi All, I'm buying a home built in 2013 that uses a tankless Rinnai water heater. I know the current owner's never flushed or serviced the unit, and I'm trying to decide the best course of action. 1) The seller can hire a plumber - probably the cheapest they can find - to service the unit and provide us with receipts. 2) I can get a credit for the service and hire whomever I want - a competent plumber - to take a look at it. My concern is that since it's never been flushed or serviced at all, if I get a credit, I'll hire somebody good and they'll tell me it needs to be replaced, by which point the house and the water heater will be mine and I'll be on the hook. Can someone knowledgeable let me know what the likelihood is that a six year-old Rinnai tankless unit that's never been serviced will be in bad shape? Thank you!