It really depends on how conservative the Democrats in his district are. Take the US Senate for example, Manchin has a reputation for being a blocker on anything the Democrats want. But when you look at his voting record he votes in line with the democrats something like 85% of the time.
What Manchin is really doing is considering the people in his state and voting accordingly. The Democrats in his state are fairly conservative, but largely support the things the party wants. Manchin's votes reflect this and as such he always wins when he runs.
If Zac's distract is like West Virginia (I think that's Manchin's state), then his antics will not make him friends. If his district is a little more ~progressive~ then they'll go for him even more.
It also depends on him being challenged in the primary, if he is than someone thinks he's not doing a good job as representative. If he isn't challenged then he'll probably win again. A lot of people just vote for the party, especially an incumbent no matter how objectively awful they are.