Question
I have just switched out a timer for the irrigation system. On one line the water pressure is diminished when the sprinklers come on compared to when I manually turn it on at the valve. Is there a problem with the valve do suspect? Have you any experience with this problem? Thanks

Answer
It could be a few things.  Was there any problem with the pressure on the line before the new controller?  If not, it sounds like the valve is not opening fully.  It is normal for you to have more water when you manually open the valve...when opened by the solenoid automatically it opens to about 85% of capacity.  Manually it opens to 100%.  If the valve is fairly old, it might be worthwhile to replace it.