Shower hot water goes from hot to cold to hot to cold

[Caroline-FUN]

I have a 2011 189FBS. The hot water in the shower rotates every few seconds from hot to cold to hot to cold so I can’t get a shower. This is after I have had the hot water heater on for 20 minutes.
Something like this happened to me 4 years ago when i bought this trailer and it had something to do with the outside shower, but I can’t remember what the fix was.
So frustrating. Can anyone give me some suggestions please.

Thank you,
Caroline

 

[dustyone-FUN]

Make sure your outside shower faucets are turned off. Also check that your bypass valves are fully open or closed. The bypass valve is fully closed and the inlet and outlet valves are fully open.