Question
I have a 1.5 hp pump drawing from a lake to irrigate my yard. I have put in a
pressure tank in the system thinking that was the right thing to do. I am
unable to balance the system, as the pump will intermitently start and stop
for short periods. Obviously there is a pressure leak somewhere, but since
the irrigation system is 50 years old. I can't trace the problem. Is apressure
tank even necessary? Can I eliminate the tank and then just let the pump run
when the timer says to run? Thanks


Answer
Thanks for the question.
Yes you can run the pump without a pressure tank. Rather than using a pressure switch to activate the pump you utilize a relay/ contactor. You controller should have a pump start or master valve terminal. When the controller starts an irrigation cycle it puts out 24 volts to this terminal also. The relay commonly referred to as a, pump start relay, switches the high voltage to the pump. The only risk you may have with the present leak is the possibility of losing prime on the pump. If you can leave the pump off for a few days and then turn it on without repriming, then I would say it will be OK.
If you want to try one more thing to locate the leak this may help. Buy some cheap shampoo and put a cup of it in the pump. Leave the pump power on over night and allow it to leak. The next morning you may find a foam bubble in your yard. I've had about 50% success with this method. The other think you may want to look at is the check valve before the pump. That could also be the problem.