2nd Time Leak at Hot Water Mix Valve Assembly in 2020 T@B 400

johnfconway

Was able to locate drip. All 4 connections to brass 4-way are tight. Would have to take this apart to see if brass is compromised on underside.

Winterized using thorough blowout technique. Our normal lowest winter temperature is 15 - 18 degrees, once or twice. This year we hit 9 degrees. One apricot tree is not happy.

Has anyone had a leak at this fitting? Using blowout technique, could enough water have pooled in brass fitting to have frozen and cracked the brass? Cannot feel any crack on bottom side.

Sharon_is_SAM

@johnfconway - @BrianZ had a bleeder screw leak here:  https://tab-rv.vanillacommunity.com/discussion/6811/need-help-mixing-valve-leaking

johnfconway

Thanks @Sharon_is_SAM. Not sure what did the trick, but leak has dissipated after tightening a second time. While in there a board was off, and I posted it with photo to gauge if it really needs to be there.

BrianZ

Our mixing valve bleeder screw hasn't leaked since using the blue Loctite I mentioned at the end of the link @Sharon_is_SAM posted.  On the other hand, just tightening lasted 3 years, and it's  only been a year since the Loctite application & a new washer.  Although, without having to tighten it each year, I'm expecting it will be less likely to crack the washer, as happened last year.

johnfconway

johnfconway said:

Was able to locate drip. All 4 connections to brass 4-way are tight. Would have to take this apart to see if brass is compromised on underside.

Winterized using thorough blowout technique. Our normal lowest winter temperature is 15 - 18 degrees, once or twice. This year we hit 9 degrees. One apricot tree is not happy.

Has anyone had a leak at this fitting? Using blowout technique, could enough water have pooled in brass fitting to have frozen and cracked the brass? Cannot feel any crack on bottom side.

Another leak started on recent trip. This time it may be the plastic nut (into brass) on the left side. It's really tough getting just enough torque on these nuts without breaking something. Also, not much of a gasket for sealing. Just out of curiosity, has anyone been in situation where you had to replace the brass 4-way fitting?  Thanks!

johnfconway

All 4 plastic nuts gingerly tightened to the max. Unlike postings for T@B 320 mixing valves, the set screw for the plastic mixing valve is removed from water. Makes me wonder if the large brass fitting is cracked this time on the underside.

johnfconway

Somewhat well hidden is bleeder screw under the right side plastic connector (in photo taken from inside trailer). Left side if you are accessing through flip-up door on outside. Thanks to @ericnliz and @BrianZ for posting in different thread for 320. Removed screw and sure enough the little gasket was split and green from metal reaction. Will get new gasket and Loctite Blue 242 for threads. Then partially fill water and Alde tanks and pressurize to see if that was leak source. Hopefully it is not the brass fitting!