Black Tank Flush Check Valve - B & B Molders Model 571
Just passing on some info regarding above. 2 weeks ago I noted a slow leak from the noted valve (which in my 2011 Mountain Aire Mod 4336 is located in the rear bathroom, under the sink and towards back corner of the cabinet). It is a black plastic molded item with a plastic inlet line and a 90 degree outlet with another plastic line. There is a check valve in between the two connections. The purpose of the valve is to allow black tank flush water to enter the tank but not return. In my case the check valve was not sealing properly when the black tank water line was connected to the flush system in the water bay even when the outside faucet was turned off. The residual water in the line would leak past the check valve and drip inside the bathroom cabinet. I removed the valve itself, soaked it in vinegar for a few hours and then poured olive oil into both the inlet and outlet connections of the valve. I assumed the valve might have been suffering from hard water deposits but that is just a guess. Later in the day I reconnected the valve and it leaked a very small amount when the black water line was pressurized as well when it was not pressurized. As a result I emailed B & B Molders of Mishawaka, IND and they were quick to phone and email me back. They advised they had very few failures of the valve and would send me a new one free of charge, no shipping charges and a self addressed envelope to return the old valve. I was very happy with their response and the in-depth phone call I had with them to try to diagnose what caused the failure. I should add that the sales manager advised that water pressure of less then 7 psi might not allow the check valve to seat properly and therefore residual water in the water line inlet might bypass the check valve but I had never noticed a problem in the past when I left the line connected and faucet turned off. A new part is approx. $29. I asked about using brass valves which are on the internet at about $64. I was advised that the plastic molded part should not be any less reliable then brass. I thought this information would be of value to other owners. I suggest you may want to keep an eye on your black tank flush check valve when using the system to prevent any disasters from occurring in your bathroom cabinet from a leaking valve.
Darrell Madill - 2011 Mountain Aire 4336