Class C wont take water

[Randy]

I have a 2014 Melbourne 29D that will not take water- It worked fine up until taking out of storage this spring. No matter what valve setting I use, city water-fill water tank-sanitize lines nothing. Water does make it inboard of the check valve (slightly), when I depress it about 8 ounces of water comes back out. The valves turn smoothly and feel normal. There are no relevant downstream bypass valves in this unit. I winterize it myself, and have since new, consider myself proficient. Any ideas?

[wabirch]

Can you get low pressure air into the line, disconnect from pump and see what it is getting through?

[Randy]

Thanks wabirch-- I have not started diagnostics yet, hoping for a response from someone who has experienced this-- Air is a great idea, (not as messy as water) The 6-8 oz of water that comes back after a fill attempt may indicate it is only making it in a foot or so?