Greetings, this is definitely the first time I’ve seen this. Not sure if it’s acceptable with this size pipe/run combination. Definitely going to notate the sag in the horizontal run and inadequate rise but wondering specifically about the connection at the draft hood.
What do you think?
Calling out the plastic pipe near the flue?
It could use some sheet metal screws. I always like to screw the draft hood to the water heater too.
Missing draft hood adapter… they just stuck an elbow right onto the hood. Pex should never be piped directly to a water heater. Amateur installation.
In UPC. It is allowed in IPC.
It depends on the PEX used, regardless of code. Some PEX specifically instruct you not to do so others allow it. However, I’m not going to spend time figuring out what PEX was used. To me, PEX is PEX. If I see PEX piped directly, it’s going in the report. If you wish to ignore it, it’s up to you 
What about the tape on the b-vent connections? In school we were taught that was a no no because it hid connection and any defects with it from view. With everything else in those images it wouldn’t be surprising to find some pipe joints are only held together with tape.
Tape belongs on a dryer vent, gas vent should be 3 screws per connection if single wall or twist-locked if b-vent, supported as necessary by proper straps/brackets.
Encourage home inspectors to ignore local codes and assume something is incorrect based on their “feelings” is ignorant and unprofessional.
You have a regular track record of quoting codes with no reference. The majority of the time you are incorrect. You always assume the OP lives in po dunk Minnesota. Codes vary state to state.
Good one!
Love is in the air 
Morning, Brian. Hope this post finds you well.
There is a first time for everything they say.
I like to turn to InspectAPedia ® for rules and standards.
1: Clearance is suspect. 1" inch for B vents but the manufacturer has the last word. 
Hard to do without a label.
2: Draft hood style/type and connection.
Did you try to move the draft hood to ensure it was secure to the water heater cabinet?
3: Flue support. I do not observe any hanging support straps for the flue pipe.
4: Flue Slope. The vertical flue run is not sloped.
Got some great posts from members.
Thanks for sharing.
Robert
I prefer lowriders myself:-)
Robert did you slam that truck yourself?
No unfortunately. I downloaded the image from google.
Here’s my work ride. Colorado 16 Midnight Edition with cool air intake. Lowride the unit in 2022 hopefully.
We have a High Horse and Jeffrey doesn’t!..Nyah, Nyah, Nyah… 
Can’t help but to luv an old crotchety guy like you. 
