Drainmaster Electric Sewer Dump Valves.

[Bill Lampkin]

I have a love-hate relationship with these Drainmaster valves. Love 'em when they work, but boy are they a pain when they don't. I took a big leap last year and replaced both with Drainmaster's new Pro Series 3" valves:

https://drainmaster.com/rv/pro-series-smart-electric-waste-valves?gclid=CjwKCAiA1rPyBRAREiwA1UIy8CZjva6t357cEp9bPGRKLP6Xngakkmymu3QwZ1LYPEwnpP0cKAtbPxoCFDcQAvD_BwE

They look similar, but the new model valves seem to open and close with more authority. The main problem for me with the old style valves was that after some use, the valve would refuse to open (or close). I initially thought that the motor was fried, but I found that by loosening the flange screws just a 1/4 turn, the problem would go away for a while. Access to those screws, for me, was a big problem. I modified my wet bay by cutting the white back panel into 3 sections to allow easier access to the valves. And I made up a long allen key so I could operate the emergency override when needed, thru a hole in the back panel.

The new style valves come with a new switch panel; The advantage is that 12v power now connects directly to the valve, and the switch acts as a relay, opening and closing the valve. Last summer was the first time we had no problems with our dump valves since we bought the coach in 2015.

[Bill Lampkin]

One more tip; Use the black tank flush each and every time you dump your tanks!

[David T. Richelderfer]

Bill - It sounds like you and I had the same experience with the older style gate valves.  They seem to be a bit weak, especially as you say if the four bolts are a bit too tight.  Both of my gate valves are sticky.  I have to push the open/close switch over and over until the gate will finally move.  After that, it seems to work okay until I don't open it again for a week or two.  Until I read your post I didn't realize DrainMaster had a new and improved gate valve, the Pro-Series S2VT valve.  As I understand their description, the new valve has full 12v connected directly to the valve instead of the 12v having to travel through the toggle switch causing a voltage reduction.  That fix makes some sense!

I would order a pair of the S2VT valves right now... but getting to them behind that stainless panel for replacement takes me some weeks or months to work up to.  lol

[Bill Lampkin]

Access to the valves was the biggest issue, not so easy for you to section your stainless panel for better access. On the Drainmaster website, there is a photo of the new valves mounted in front of the wet bay back panel. They just extended the tank drain in front of the  panel, then tied both drains together with a 'wye' right above the sewer hose connection. Well, a picture is worth a thousand words.....Anyway, that fix would not work for me, as the maniblock valves are in the way of the black tank drain. One could relocate the maniblock valves, oh well, here we go.

The new style valves do seem to work better, and the new switch design lets you add as many dump valve switches as you like, so you can operate the valves from inside the coach, if you wish. THe switches act as a low side switch, just like your water pump has several switches you can use to turn on the water pump. I'm not willing to put in a remote switch, as doing so without being sure the sewer hose is connected and tight is not a sight I want to envision!

[Frank Bergamo]

Gentlemen, I found that if I dump with coach plugged in or the coach running, the higher voltage allows the “lazy” valve to work better. Hope this helps.

[Lee Welbanks]

What happens is the top works of the valves get full of crap,soap residue and what ever else gets run through them, when I still had them in the coach I have taken them out and flush cleaned both valves and re-lubed them and with that they would work for awhile and then hang up again. My main problem is that Monaco mounted the valves flat/horz which is a absolute no no with a gate valve and the top works of the valve fills up with junk. There is no way to re-pipe the tank discharge sides to solve the problem. I just took the valves out and put manuals in, I going to install two cable operated valves here pretty soon, I got the high end cable operators that have SS cable and sealed jacket, we'll give that a go and see what happens.