Leave drains open

[MAMalody]

Question. In freezing weather should my grey water drains be left open? I have a 2003 3575RL.

[rldriver]

Mike, when we spent last winter in Ephrata Washington we kept our front grey water tank open all the time, and it got down to -10F. Our drain was steep and only about 3' long.

I think I would be concerned if it was a long hose with a short elevation drop that the water could freeze and cause a problem.

Dick

[H. John Kohl]

I agree with Dick. I would want to control when that water was running through the pipes for a couple reasons. I do know warmer water freezes faster then colder water. If the shower or washer was draining it would be warmer. Also I feel those types of draining events are more of a drizzle than a good gush and could have a bigger chance of freezing up and clogging up by the layering effect. The big gush from a tank dump has more force and you can pick when it happens hopefully in the warmest part of the day even if it is below freezing.
These thoughts are my opinion and I do not have technological information to back them.

I am waiting to here from those who brave the freezing in their Montana. Icehouse, comes to mind.

[stiles watson]

We have been in weather that freezes almost every night and sometimes does not thaw during the day. We leave our gray tanks closed. I figure I need them to finish the cycle when dumping the black. My sewer line is the 1" Sewer Solution. Before retiring for the evening, I have to remember to chase the water from the line to prevent freezing in a low spot.

I posted about the problem with wash water overflow due to a frozen spot in the discharge line. I also disconnect the Sewer Solution pressure line and the tank wash line after draining the tanks. It is a bit more trouble to deal with the freeze hazards of cold weather, but I would not leave the tanks open. Our overnight temperatures have ranged into the lower 20's at times. There appears to be no threat of tanks freezing. We keep out thermostat at 61 at night and that still pumps enough heat into the belly to prevent freeze up.

The heat tape and insulation on the fresh water hose is a must. I am parked between two Class A buses. It has been interesting to watch these guys thaw out frozen fresh water lines because they don't check the weather or use heat tape.

[ols1932]

For all the obvious reasons about freezing when water trickles, I don't recommend leaving any of the drains open. It's much better to have the liquid from a tankful running out at one time because it will get to the sewer quicker before it has a chance to freeze. Also as previously mentioned, you really need the grey water to back flush the black water tank when dumping.

Orv

[Icehouse]

We leave our gray tank open all the time. Caveat, we do not use a cheap sewer hose. We went to a rubber supply store and purchased one of those black and green rubber hoses used by elephant trucks to suck out city drains. Next, our sewer line drops nearly straight down (for a total of about 2 feet) straight into the ground. (This is due to some VERY clever and fancy parking by Bernie). Our internal lines and valves are heat taped and we haven't had a problem. Today is way below zero and the only problem we had was our convenience center getting a little chilled. Hair dryer solved that.

Moral of the story: if you have one of those blue or red hoses, I'd leave my tank closed and dump all at once. Also, if you have to walk it out, I'd never leave it open to trickle or drain. Trickling will cause BIG problems.

On edit: I agree wholeheartedly about needing the gray tank to flush the line after dumping the black tank. We use our galley for that. I don't know if you have a separate galley tank or not. If not, another reason to leave your gray tank closed.

[sreigle]

Having once had ice accumulate until it totally closed off the sewer hose, causing water to back up into the dump pipes and then freezing those under belly dump pipes, I'll never again leave any tank valve open during freezing weather. Just my preference but I sure don't want to risk another occurrence of that problem.

[MAMalody]

The reason I asked the questions was because the park I am in, the combined opinion is that you leave the gray water open and close the black with some antifreeze added to it. I agree with the logic expressed above. I have been keeping my gray drains closed along with the black. I do keep the valve that I installed at the end of the rv drain system. I have had trouble with the galley gray water valve freezing. It is outside the basement. I have put some antifreeze in that holding tank to see if that helps. It was RV antifreeze so it may not do much. Any other input is welcome.

[sreigle]

Good point, Mike. I also leave that extra valve open, the one I added at the end of the dump pipe. Someone noted on another thread that that valve will freeze closed if left closed in freezing weather. They are correct.

I had that galley tank valve freeze once, also. Filling the tank with hot water took care of it. But that only works if have enough available capacity for the hot water and not so much cold water that it renders the procedure ineffective.