Black water tank flush system

[aztrooper]

Dumped my black water tank today and decided to flush it, which I haven't done for a while. I know, I know. No remarks about doing it every time. Hooked the hose up to the flush inlet and turned on the water. Heard the water pressure build up but it did not flow and could not hear it spraying. Turned the water off and on several times but no change. I could hear a clicking sound. Did some research on the internet and found that some have back flow valves so I think that is what I heard clicking. So my question is, where is the sprayer located on the tank and how do I get to it. I read also that using a chemical called Unique RV Digest-it can clean off the sprayer head with out taking it out of the tank. If I can find that, I will try if first. My RV is a 2007 Forest River Georgetown 378XL which we are living in inside our garage while building our house on the other side of our building.

[bubbles]

Your 2007 GT 378 looks the same as my 2012 and access to the tank sprayer is from behind the water heater. You will have to open the hatch surrounding the water heater. It is a pita but doable.

[D W]

I sure hope you allow for adequate ventilation (air exchange) inside that garage.

[Skip12]

Starting with inspecting / replacing the antisiphon valve seems easier and less messy to me. That's where I'd start.

[Flybob]

The back flow valve is normally in the hose connection on the side of the RV or in the wet bay. Occasionally they are installed backward.

[5picker]

I don't know about Georgetowns but all R/V's I've owned the black tank flush backflow/antisiphon valve was under the bathroom sink or behind the shower.



Oh... and don't beat yourself up about flushing EVERY time. There is no need and until just several years ago, (10-15) black tanks never had a flush. Many units still don't.

[bubbles]

Originally Posted by Flybob

The back flow valve is normally in the hose connection on the side of the RV or in the wet bay. Occasionally they are installed backward.

The backflow check valve/vacuum breaker for black tank cleanouts is normally installed inside the unit above floor level (at least 6" above toilet rim) under vanities, hidden in walls etc. There is no check valve at the input port (typically). In the OP case it is probably where mine is located; in the washer/dryer provision closet about 5 feet above the floor.

[jbrosecity]

This is actually pretty common... the saniflush nozzle in your black tank is probably same as mine on several different coaches I had,,, Just a plastic cup which is bolted down into the tank with tiny pin holes in it - lousy cheap design but this the most common approach. Those pinholes plug up easily either with tiny debris particles or more likely hard water deposits. Just happened to me on my new 2019 Forester. Having been thru this before, I instructed the warranty service tech to pull it out, drill all the pin holes out a little larger and as before that cured it 100%. Forest River covered it on warranty, but if no warranty it is an easy fix... I did it on two other coaches in years past. See the diagram below.

[bubbles]

Originally Posted by jbrosecity

This is actually pretty common... the saniflush nozzle in your black tank is probably same as mine on several different coaches I had,,, Just a plastic cup which is bolted down into the tank with tiny pin holes in it - lousy cheap design but this the most common approach. Those pinholes plug up easily either with tiny debris particles or more likely hard water deposits. Just happened to me on my new 2019 Forester. Having been thru this before, I instructed the warranty service tech to pull it out, drill all the pin holes out a little larger and as before that cured it 100%. Forest River covered it on warranty, but if no warranty it is an easy fix... I did it on two other coaches in years past. See the diagram below.

I believe this is what's installed by the factory in the OP's GT 378 but yes does sound like the tank nozzle is clogged.

[Larry-NC]

Originally Posted by 5picker

Oh... and don't beat yourself up about flushing EVERY time. There is no need and until just several years ago, (10-15) black tanks never had a flush. Many units still don't.

Neither our 2007/8 Cherokee 38P Destination Trailer nor our 2002 SOB have flushers.

We've never had an issue.

Larry

[5picker]

Originally Posted by Larry-NC

Neither our 2007/8 Cherokee 38P Destination Trailer nor our 2002 SOB have flushers.

We've never had an issue.

Larry

10-4.

I'm often amazed at the folks that think they need to have crystal clear water running from the black tank after each use. Totally not necessary.

In all the units we've owned with black tank flushes we've only ever flushed every 3-4 times out, if that. More than that is a waste of water. It is a holding tank.

Do I keep some water in it after dumping.... sure.
Do I make sure it's as clean as new... nope.

[RELHUB]

Originally Posted by jbrosecity

This is actually pretty common... the saniflush nozzle in your black tank is probably same as mine on several different coaches I had,,, Just a plastic cup which is bolted down into the tank with tiny pin holes in it - lousy cheap design but this the most common approach. Those pinholes plug up easily either with tiny debris particles or more likely hard water deposits. Just happened to me on my new 2019 Forester. Having been thru this before, I instructed the warranty service tech to pull it out, drill all the pin holes out a little larger and as before that cured it 100%. Forest River covered it on warranty, but if no warranty it is an easy fix... I did it on two other coaches in years past. See the diagram below.

Great Information thanks for posting this
I will keep that for when I have this problem

[Iggy]

Here is some pictures of the location.
I had the same problem and the spray nozzle got plugged with C***P.

Difficult to get to as you need to remove the water tank outer ring from the water tank housing then go under and unscrew the metal L brackets from the frame and lift carefully and prop up.

I removed the nozzle and landed up drilling out the hole and making it a larger hole for spraying.

Good luck.

[bubbles]

In my GT378 the spray nozzle is behind the tank toilet drop so the spray function is worthless. When mine clogged I just punched through the nozzle with a bar to open the nozzle spray holes end completely (made it a flow through). I empty the tank/fill it back up/empty once again and good to go (level indicator is always correct). My nozzle is spun welded to the tank and I didn't want to deal with that also. Yes, for me it was a bummer getting to the nozzle.

[Indy500]

Do all the newer RV,S that have a black tank flush system have the check valve that everyone is talking about?

[Iggy]

Originally Posted by Indy500

Do all the newer RV,S that have a black tank flush system have the check valve that everyone is talking about?

Actually all the water lines that go into the rig have a small spring loaded one way valve.

Iggy

[Hclarkx]

If I can borrow the thread .....

My 2015 Rockwood Ultralite black tank flush seems to work fine (quite an audible spray) but when I turn off the water and disconnect the hose at the black flush female hose fitting on the side of the RV, I get a regurgitation of a cup or two of water under considerable pressure. Is this normal?

[Mr. Dan]

Originally Posted by Hclarkx

If I can borrow the thread .....

My 2015 Rockwood Ultralite black tank flush seems to work fine (quite an audible spray) but when I turn off the water and disconnect the hose at the black flush female hose fitting on the side of the RV, I get a regurgitation of a cup or two of water under considerable pressure. Is this normal?

The vacuum breaker/check valve being discussed is at least 6” (typically) above the top rim of your commode. Without being familiar with your trailer, I’d say you would have 1-2 cups or more of water in the line between that high check valve and your hose connection. I can’t speak to “considerable pressure” but my Wildcat rids itself of that water fairly quickly.

[bubbles]

Originally Posted by Iggy

Actually all the water lines that go into the rig have a small spring loaded one way valve.

Iggy

That's true however, the one for the black tank cleanout is located on the output side of the vacuum breaker/ check valve and not at the input port. Any others are at the input port.

[bubbles]

Originally Posted by Hclarkx

If I can borrow the thread .....

My 2015 Rockwood Ultralite black tank flush seems to work fine (quite an audible spray) but when I turn off the water and disconnect the hose at the black flush female hose fitting on the side of the RV, I get a regurgitation of a cup or two of water under considerable pressure. Is this normal?

This is normal (amount does vary with where the vacuum breaker/check valve (VBCV) is located within the unit). It's your input fresh water coming back out of the line from the VBCV as the vacuum valve closes off the input side of the valve. In fact that's the reason for the vacuum breaker which is vented to ambient within the VBCV. It's not anything from the black tank.