The property management company explained to me that they believe he is not liable because when he did the work he never interacted with the pressure valve since it is not located near the igniter that he replaced. 

The success of a big center like that is the property management and how well they interact with tenants and maintain the center. 

Again, the BiggerPockets store has some books for this or you can learn by watching podcasts, reading blogs, and interacting on the forum.

Let's get @Dave Foster in here...I have not heard the 'two year' restriction after purchase on all 1031s...it may only apply to related party exchanges? 

@Dave Foster

IPX1031 is one of the biggest players, @Dave Foster should be talked to as well!

If not buying a multifamily you need to find the right lay out to interact with tenants as little as possible.In regards to resources, check out meet ups in your area and connect with locals you'll find the most common use strategies and you can start narrowing down your options. 

There was a lot of learning and fine tuning of my system/process along the way: make your listing as accurate and transparent as possible - are bathrooms shared, is it noisy at night, what is unique/peculiar about your place, what is provided for guests, what is kitchen policy, how many nights is an ideal stay, how will you be interacting with guests etc. 

So much knowledge and interaction.  

@Dominique Yuan  I tagged Dave Foster on your questions is a local expert that handles 1031's and should be able to give you an answer.