Question
Hello,

I just installed a underground sprinkler system in my front yard.  The yard is 40*80 feet.  I have eight spray heads with spray distance of 10 feet at 25 psi.  The water is from my garden hose, with static pressure of 80 psi and flow rate of 10 gallon per minute.  The problem is that water pressure is very low for the system so it barely works.

I have two solutions.  One is to try to find the main water line and to get water from that.  That will involve more digging as the grass is three years old.  The other solution is to get a water pump. At Lowes, I was recommended with a sprinkler water pump with both inlet and outlet pipe size of one inch.  I need converters to connnect the pump to my system at 3/4 inch.  

My question for the pump option is: is it appropriate to change the pipe size for the pump?  How to coordinate the two timers, one for pump and the other for sprinkler?

Thank you very much.

Edwin

Answer
Honestly, with the amount of pressure you are describing, I can't imagine that you would need a pump for such a small system.  First check to make sure that all the valves supplying water to the system are fully open, that your water meter is fully open, and all drains are closed.  If this is already true, and the system is still not working, I would suspect a line sizing problem or there are too many heads on each valve.  A pump can help with this, but your results may not be as good as you would like.  It would be approptiate to change the fittings at the pump to match the line size.  Most timers have a wiring terminal for a pump or master valve that would turn the pump on when the system starts.  However, you probably need a relay switch to operate the pump which is 120 volts from the timer which is 24 volts.