Important info for winter time use and over pressure of solar powered water pumps.by mark fuqua on 02/19/12
Probably the largest cause of failure we see in solar pumps during the winter is over pressure. Over pressure can be caused by several different problems in a solar pump installation. Probably the largest cause is lack of or faulty weep or drain hole in the drop pipe in the well during freezing weather. There must be a small hole in the drop pipe in the well below the frost line to allow the water in the pipe to drain when the pump shuts off so the water can't freeze in the pipe and cause the pump to come on against a frozen pipe. If the pipe doesn't drain and freezes solid with ice and the pump comes on it is like pumping against a valve that is shut off and causes the pump to create extreme pressure and damage. Even a properly installed weep hole can become clogged due to dirt or debris or hard water being pumped through the pipe over time. Please check your weep hole at the beginning of ever winter. Also the pipe going to the tank must be allowed to drain properly. There should be no loops, low places or sags in the pipe that delivers the water to the tank or the pipe can freeze solid and have the same effect of damage as a plugged or non-existant weep hole. Please make sure your pipe going to your tank can drain properly. If you have installed some type of valve or shut off on your pump delivery pipe, please make sure that the valve can not be turned off while the pump is pumping. This is a direct restriction to the pump and will cause damage. Unless you have installed a pressure tank and switch as is used with many ac pumping systems, you can not close the valve while the pump is trying to run. Attention to these important details can save solar pump users many dollars in repairs to their solar pumps. Thank you.