On 5/30/2016 9:55 AM, Kurt V. Ullman wrote:
I have a line of about 5 heads. The ones farthest away from the valve are
working perfectly. The 3 closest to valve only go part way up and if I manually
pull them up, they often stay up even after the water is turned off.
The farther ones working would tend to argue against pressure issues. Does
it seem the best idea to just replace those three or is there some other
diagnostic trick I should try first?

Swap them. See if the problem moves with the heads or follows the location.