Tanks drain slow

**hampal** · 08-16-2020, 02:32 PM

Is it just me? Seems like it takes forever for my tanks to drain. I'm talking black and both grey tanks. I can easily spend 30 minutes at the dump station trying to completely drain all 3 and none are than 1/3 full. Should I not drain completely? Like when things slow to a trickle just close the valve and move on to the next tank. Fwiw the rig is level.

Our rig is a 2020 Imagine 2500RL.

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**Skiddy** · 08-16-2020, 03:13 PM

Something is not right. Tanks empty best when more than 2/3 full IMO. Mine is maybe a 10 to 15 minute event. Black takes a couple of minutes, close the black valve. Then open my grey #1 , which is the kitchen. Meanwhile I hook up the black tank flush and let it run. The front grey is the slowest due to a long flat run. After maybe three minutes I close it. Open the black again for a rinse. Once it looks ‘clean”, close the valve and then go and shut off the rinse hose. This puts a couple of gallons in the black tank to slosh around and clean the tank while driving. The grey #2 , shower is emptied last to “clean” the sewer hose. If I have time, no one waiting, I’ll rinse the sewer hose with the hose that was connected to black tank flush. Tanks are all pretty much empty. Run some water into the greys to slosh around and done. We always drive with about 1/3 in the fresh tank.

**azink007** · 08-17-2020, 12:59 AM

I’ve noticed that as well and it seems to be most noticeable with the galley (grey #1) because it’s a long, relatively flat run. I drain both gray tanks at the same time because after the initial rush of water it just seems to trickle out endlessly. I usually shut it after no more than 5 minutes and just accept that there will be a few pints left in the tank.

**boyscout** · 08-17-2020, 12:40 PM

Originally Posted by hampal

Is it just me? Seems like it takes forever for my tanks to drain. I'm talking black and both grey tanks. I can easily spend 30 minutes at the dump station trying to completely drain all 3 and none are than 1/3 full. Should I not drain completely? Like when things slow to a trickle just close the valve and move on to the next tank. Fwiw the rig is level. Our rig is a 2020 Imagine 2500RL.

Your trailer is pretty new but it's possible that draining tanks when they're not very full is contributing to the problem. It's also possible that because you've apparently drained to the last trickle and (I'm guessing) not added some fresh water back into the tanks after draining them that some solids have accumulated in the tanks or their outlets and/or in the dump outlet pathway.

Water is a very important component in keeping tanks clean and flowing well. Much better to dump them when they're full or near-full - I've actually run water into the sinks and used the black tank flush to increase the water in the tanks before dumping them. Great idea to add something to the tanks; there are various commercial products specifically for tank cleaning and / or you can add Dawn dish soap and water softener (look up "GEO Method" on the internet). For a problem like the one you're having I'd be filling the tanks 2/3 full and adding soap and softener generously, letting it sit for hours, and then going for a drive to slosh it around inside the tanks. And a great idea to add at least five gallons of fresh water (and chemical or soap) to each of the tanks immediately after dumping them, to prevent any remaining solids from solidifying and sticking to the tank or its outlet.

Also consider adding a gate valve to the end of the dump pipe. Many of us have to do this because our dump system won't drain itself completely no matter what we do - stuff gets stuck in the outlet pathway - so several cups or more of sewage await us at the end of the dump pipe after the trailer has been moved to the next site and we're setting up again. We add this valve to the end of the dump pipe:

https://www.valterra.com/product/twi...e-valve-boxed/

No more surprises when we remove the dump cap - they are held back behind the valve - but in your case that valve would give you another opportunity to resolve your problem.

You could put lots of soapy water in the tanks and then pull the dump valves for the tanks so that the soapy water fills the entire dump path all the way to the new gate valve you installed on the outlet. Let that soak for hours or more and then dump and the procedure might remove any solids that are obstructing your dump pathway AFTER the tanks, the piping that carries sewage from the tank to the end of the outlet pipe.

Good luck.

**Postaldaddy** · 09-06-2020, 02:21 PM

The black tank installation on the 2020 375RES is the culprit. The pipe from the black tank actually goes up hill to go over a frame cross member before going down hill to the hose connection. When I can figure out how to post pictures I will show what the repair shop found and showed me.

**livinthelife** · 09-06-2020, 03:29 PM

Originally Posted by Postaldaddy

The black tank installation on the 2020 375RES is the culprit. The pipe from the black tank actually goes up hill to go over a frame cross member before going down hill to the hose connection. When I can figure out how to post pictures I will show what the repair shop found and showed me.

To post pictures you have to have a paid membership.

**J Maguire** · 09-06-2020, 04:37 PM

[QUOTE=hampal;314158]Is it just me? Seems like it takes forever for my tanks to drain. I'm talking black and both grey tanks. I can easily spend 30 minutes at the dump station trying to completely drain all 3 and none are than 1/3 full. Should I not drain completely? Like when things slow to a trickle just close the valve and move on to the next tank. Fwiw the rig is level.

Our rig is a 2020 Imagine 2500RL.

Sent from my SAMSUNG-SM-G930A

I've had three RVs and used them all a lot so very familiar with dumping and keeping the tanks operating well. I'm also using the same location to empty as I did all the other RVs. My new Grand Design is horribly slow when emptying!