Checked Coffee Machine unit and found low water flow to tank. Checked fill valve, dispense valve and all hoses and connections. Found right side check valve between fill valve and tank stuck partially closed. Removed and tried to free check valve would not work, will need replaced. 9-6-19 Returned with part. removed old check valve from the right side and installed new check valve. checked operation of unit, okay. customer said the left side was not brewing right either. found that the brew port was blocked with lime. cleaned out port and checked operation, okay. both sides were brewing the same level. also installed customer supplied filter. checked all operation, okay.