Help draining Black/Grey tanks

[JPz]

I have a brand new Montana High Country 334BH. This model has an extra 1/2 bath in the rear bunkhouse. I did not get a very good run thru on this from the dealer (I assumed it would be similar to my old 5th wheel). I simply do not know how to drain everything. There is a outlet to hook the sewer hose to around the middle/front of the unit then a second one at the rear. In the Water center there is a black and a grey valve, a few feet away from that by the first sewer connection is a small door that leads to another valve. Then, there is yet another valve on the frame, behind the slide near the rear sewer connection. We took it out on it's maiden voyage recently, when it came time to dump, we pulled up to the first connection, pulled the grey in the water center, then the black, then the extra grey one on the frame (I assume is the Kitchen), when finished, pulled up to the rear sewer connection, once again pulled the grey and black in the water center, then the last valve on the frame near the rear. When all was completed the panel read 2/3 full on black2. Is this the correct process for this unit and how do I clear the black2 tank? This is quite a setup, and also why are there valves underneath, these are very uncomfortable to get to when dumping.

[rohrmann]

Typically, you drain the black tank(s) first, then the grey tanks, so the grey waste water makes the inside of the hoses a little less nasty, than draining the black tanks last. If you know which grey tank contains galley waste, that one probably should be drained before the other grey tank.

[AZ Traveler]

Jeff,

First, welcome to the forum!

Your black tank fill indicators are very unreliable and basically useless. It only takes a piece of TP stuck in the tank to give a bad reading. Once you use your rig you will get a better idea of how often you need to dump.

[RMcNeal]

Once you drain the black and gray in the convenience center, and the galley gray tank, then pull up to drain the rear black tank, you do not need to pull the valves in the convenience center or galley tank again. The rear black tank for the half bath has its own valve. You can either put 2 hoses on the 2 outlets with a wye connector to the sewer or do them separately, but the rear black and the other 3 front tanks don't connect to each other.
Sorry if I misunderstood, but it appears you were saying you moved up and hooked to the rear outlet then pulled the front 3 valves again. Not necessary. Those tanks are done.

[Smlkripp4]

Originally Posted by JPz

I have a brand new Montana High Country 334BH. This model has an extra 1/2 bath in the rear bunkhouse. I did not get a very good run thru on this from the dealer (I assumed it would be similar to my old 5th wheel). I simply do not know how to drain everything. There is a outlet to hook the sewer hose to around the middle/front of the unit then a second one at the rear. In the Water center there is a black and a grey valve, a few feet away from that by the first sewer connection is a small door that leads to another valve. Then, there is yet another valve on the frame, behind the slide near the rear sewer connection. We took it out on it's maiden voyage recently, when it came time to dump, we pulled up to the first connection, pulled the grey in the water center, then the black, then the extra grey one on the frame (I assume is the Kitchen), when finished, pulled up to the rear sewer connection, once again pulled the grey and black in the water center, then the last valve on the frame near the rear. When all was completed the panel read 2/3 full on black2. Is this the correct process for this unit and how do I clear the black2 tank? This is quite a setup, and also why are there valves underneath, these are very uncomfortable to get to when dumping.

Have you figured this mystery out? Even our dealer has no idea of the correct answer. We actually have a black tank #2 flush in the main water cabinet but when connected it’s as if water goes no where. So frustrating and we really don’t want to stick a hose down the back toilet I didn’t spend this much money to have to flush like that

[Delaine and Lindy]

Not familiar with your 5th wheel. However, I always empty black tank first, then the grey tanks. I then run water back into the black tank and drain, put more water back into the black tank, drain again, repeat until the black tank water runs clear. Don't forget to put 3+ gals back into the black tank. Never leave the water running into the black tank. Don't ask why! Good Luck.

Happy trails.

[rider71]

On my '03 Big Sky I have 3 tanks. The galley tank drain valve is outside close to where the galley is and I leave that open all the time. The T handle is pretty obvious, easy to reach, with a longer rod that goes up into the belly. Whatever you do, do not let any kind of grease that can solidify go down the kitchen sink drain... not even butter. Wipe your dishes down first, they should look almost clean when you wash them. (For the new rv'rs ).
The black and grey water tank drain valve T handles are located in the forward storage area on the wall underneath the sliding storage trays. Open the large storage door and look down and forward (toward the hitch) and they're pretty conspicuous and both T handles should be marked. Pull the Black first making sure your hose isn't kinked or sagging so that it drains smoothly, it should positioned so that it's in a relatively straight line on a down slope to the ground waste receptacle. Close the valve by pushing it in when you hear the waste stop flowing. Then pull your grey tank T handle last so that the grey water flushes any debris left over from the black tank and close that valve by pushing the T handle in.

Before using your toilet again (especially #2) be sure to run a few gallons down the toilet by holding the pedal down - 30 seconds to a minute should do it, then drop some black tank digester and deodorizer as general maintenance and you should be good to go.

[DutchmenSport]

Your description is a little confusing, but it sound like:

You have 2 valves forward, and 2 valves farther toward the rear (middle).

The front 2 valves handles in the convenience center and they are connected to a single discharge pipe.

There are two valves handles (in the middle or farther to the rear). One is behind a little plastic door and the other valve handle is through the frame. But both are connected to the same single discharge pipe.

You have 2 discharge pipes, one toward the front, one toward the rear. Is this correct.

If so, the procedure is simple. When pulling up to a dump station, you dump the front discharge outlet first. Connect a single hose, dump the black tank first, the grey tank second.

Now pull forward and align the second discharge pipe with the dump station. Again, hook up a single hose and dump the black tank first, then the grey tank second.

Put everything up and move on.

If parked at a campsite that has a sewer connection you may want to get a sewer hose Y and hook both outlets together so you don't have move hoses so much. This works well at sites with sewer hook-ups, but at dump stations, a single hose and moving the camper forward works best.

About the sensors, they don't work. Don't depend on them. Time and experience will help you become aware of how much is in your holding tanks and when it's time to dump.

[LeftOverParts]

I recall seeing a video that someone made during their factory tour in Elkhart. The rep giving the tour showed how the front tanks are mounted and recommended raising the front of the 5vr when emptying the tanks to get a steeper slope on the drain line. Applying this thinking to a rear tank, if dumping while attached to the truck, depending on how the OP’s trailer rides (ie nose high) and where the drain ports are, the trailer might not have much slope at the back of the rig to get a good drain.