2021 T@B 400 cold water check valve

ChrisK

My daughter is having a problem with her 400. It seems like the hot water is getting in to the cold water system. She contacted NuCamp but they said to look for a check valve between the mixing valve and the Alde. The don't seem right. To me, that would keep the cold water from getting in to the Alde but not the hot water from getting in too the cold side. I'd think she needs to look for a check valve on the cold line going in to the mixing valve. Is there one? Anyone know where it is? Am I thinking that through incorrectly? And no, its not just the faucet mixing. It happens for all faucets.

MuttonChops

What model-year 400?  I.E. Does it have the Nautilus System

With non-Nautilus systems having the Winter By-Pass set incorrectly can cause hot water to enter the cold water system.

Sharon_is_SAM

It could be a mixing valve issue.  Does it happen on both city water and when on pump?

There is no check valve on the Alde cold water feed.  Hot water can exit the Alde in this way.  It happened recently and I don’t remember the scenario.  My bet is the mixing valve.

Sharon_is_SAM

@ChrisK - here is the thread I could not remember.  This owner added a check valve as reduced pump pressure from a leak resulted in backflow.

https://tab-rv.vanillacommunity.com/discussion/14162/2021-t-b-400-water-issues-no-water-from-hot-side-of-faucet-hot-water-from-the-cold-faucets

ChrisK

@Sharon_is_SAM Thanks for the info. Looks like we have some work to do on her system. Now she says the pump won't prime which is mentioned in one of those articles. Something is allowing cross feed. I need to figure out what.