On my N2U Jayco we tried to use the water pump to sanitize the the pipes. The pump turned on but wouldn’t pump. Looking at trouble shooting I saw the screen filter could be clogged. However, after looking all over the pump system on this almost 17 year old camper, I do not see a screen filter. Is it possible that one was not installed on a camper of this age? We bought and plan plan to install a new pump. We used the city water on on maiden voyage and thankfully had no issues with the water!