unions and pex

My house is plumbed with pex, but the water heater connections are made with with 18" runs of copper flex. I noticed there are no di-electric unions installed between the flex and the tank nipples. I'm replacing my water heater next week and will add unions if necessary. Was the plumber correct to omit the di-electric unions in this case?

its ok...

they are used when dis similar metals are touching


i your case, its all plastic, so it dont matter...

no electralysis can happen..


anymore I install my heaters with quick connects
from the copper plumbing to the heater,,

I beleive they extend the lifetime of th heater..

quick connects are like dialectric unions on .....steroids......