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I have installed a 2 zone system in a small yard. The supply is from the city water plumbed from the house to my valve box. I have 52 psi on the supply pressure from the house, but when I activate one of the zones, it barely has any pressure to the heads. I can't figure out why I am losing so much pressure to my heads. I am using pop-ups and some rotary heads on this system. 3/4" poly pipe as my main line and down to 1/2" funny pipe to each head. The system is brand new and we haven't laid any sod yet so I am able to inspect the whole system. I am open to any ideas as to why I don't have adequate pressure here. Leaving the pressure gauge in the system, when a zone is activated, I end up with 30 psi on the supply pressure...could that mean that I have too many heads per zone? There are 6 heads on each zone. Thanks for any input.