the check valve on our camper, makes a little vibration sound when we have the hot water running... we got the check valve replaced, and it still does it.. is this normal ?

Are you talking about the City Water Hook Up Check Valve? If so try and take something and push the check valve in from the outside to see if this does not make it stop. Sometimes the check valve will get hung up and not close or open all the way. Good Luck

alrighty thanks we thought of that but didn't know and didn't want to break it.. will try it

well we didnt keep it long enough to do anything