To placate her, I had the oil company run diagnostics on the boiler, and they found it in safe and working condition.

They typically have better diagnostic skills.

I had 3 people take a look at it, all 3 of them took like 2+ weeks just to do a diagnostic because of how busy summer and HVAC problems are here.

So, I figure out how to make it work without using their diagnostic software and continue to work until the next glitch.

@Robert Melcher totally agree.... they've already burned the kitchen down and wouldn't own up to responsibility..... i doubt they'll start now.they've mysteriously also said the kitchen ceiling has chipping paint, and might be due to a dripping faucet, so I need to go now.....I'll probably make the preliminary diagnostic, and call in the plumber knowing they'll complain

Partially this seems to be driven by our legal system in the US which is driving cost for malpractice insurnace.Years ago I was invited to a presidents club meeting of a company selling equipment for cancer tissue diagnostics.

Agree with Dana Hoffmann Think of the walk through as a diagnostic.

Because we specialize in manufactured housing and most home inspectors don't know enough to inspect them properly, we have an employee who is properly trained who we pay plenty and we ended up buying a whole lot of diagnostic equipment for and supplying a vehicle to.

Needs good diagnostic skills and be responsive as I would like this addressed quickly. 

It might make sense to change the thing, but tell your tenant if they start seeing the same issue as they did with the last dishwasher then you will have to charge them for any further diagnostic visits.