Is it necessary to flush new supply lines for shower installations? How is this done? What is a flushing port?

Thanks

If you're connecting to old pipes it's a good idea to flush the supplies out just to be safe. If all the piping's new it's not mecessary. Flushing out the supplies can be done in one of two ways,( there is no flushing port). 1) Just before you connect the supplies to the valve hold a pan or bucket up to catch the water and turn the water on for a few seconds **or** 2) install the shower valve and before you turn the water on to test, open up the valve and remove the cartridge. Nolw turn the water on for a few seconds to flush the supplies. Nor reassemble the cartridge and test the valve. Good luck, Tom