Grey and Black tank valves

Help!!! I have been RVing for many years and dont think I am doing anything wrong before having to look in owners manual (lol), but it seems I can not get black tank to ever drain past 3/4 full. I have a Cyclone 4250 with two places to drain tanks, Gray water tank 1 box and Gray water tank 2 box. Both have 2 valaves. I am assuming if you open all four valves, both gray tnks and black tank will drain at same time. I seem to have good flow coming out of drain pipe. Why isnt the black draining more than 3/4 tank? I am thinking, possible clog or bad sensor. I dont know, but dont want to get caught on a trip where I cant use toilets. Please tell me what each valve does in each tank box. And how do I specifically drain black tank so I can tell if it is sensor or clog? Thank you very much. Hank Miller

Re: Cyclone 4250 Gray and Black tank vavles

Hank,

If you're judging by the tank sensors, know that they are extremely unreliable; particularly the black tank sensor. A bit to TP stuck on the sensor will give a false reading. Most people judge when to dump the black tank either by calendar or by the "burp" that starts when it's about full.

If you add a twist-on clear adapter on the sewer outlet, you'll have a much better idea of what's happening when you open the gate valves. You'll find additional help in our owner-written Water Systems Guide.

Re: Cyclone 4250 Gray and Black tank vavles

Look up the "Geo Method" and give that a try. See if that cleans out the tank and helps clear up the gauge. I may take a couple of times. And I suggest draining the black prior to opening the gray.

Re: Cyclone 4250 Gray and Black tank vavles

To see if your black tank is drained if the toilet is just over it, turn off the water, flush keep the ball open and look in the tank with a flashlight. If you don't see anything it is at least empty. Not clean but empty. Also make sure you have a tight hold on the flashlight.

John

Re: Cyclone 4250 Gray and Black tank vavles

Lynn1130 said:

Look up the "Geo Method" and give that a try. See if that cleans out the tank and helps clear up the gauge. I may take a couple of times. And I suggest draining the black prior to opening the gray.

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Yes . . .

Empty the black tank first, then use the water in the gray tank to back flush into the black tank to remove any clogs that might be building up.

Re: Cyclone 4250 Gray and Black tank vavles

Don't ever think that one time of draining is enough. Install the clear 30* elbow so you can see when the water runs clear. Normally take me 3-4 times to get everything out. Open the valve with the spritzer on until you have a trickle of water. Close the valve and let to spritzer run about 5 minutes and drain it again. You will be surprised how much more "stuff" comes out. Word of caution..NEVER EVER leave the spritzed on and walk away. Really bad stuff can happen.

Re: Cyclone 4250 Gray and Black tank vavles

One procedure that works for me is before a trip add one cup of Spic and Span and about 10 gals of water to the tank. Drive to your destination and after hooking up flush the black tank. Add more water with the valve closed and flush it again. Cleans out old residue in the tank. Do it again as you move to the next stop. At some point of the continued use of this process the water will come out clear with only suds.

Re: Cyclone 4250 Gray and Black tank vavles

JohnD said:

Yes . . .

Empty the black tank first, then use the water in the gray tank to back flush into the black tank to remove any clogs that might be building up.

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I guess I should have continued with . . .

Do that a couple of times to make sure you have loosened up any sticktites . . .

Then after doing what I said above in the quote . . . flush the black tank several times to finish the cleaning.

Re: Cyclone 4250 Gray and Black tank vavles

Lynn1130 said:

One procedure that works for me is before a trip add one cup of Spic and Span and about 10 gals of water to the tank. Drive to your destination and after hooking up flush the black tank. Add more water with the valve closed and flush it again. Cleans out old residue in the tank. Do it again as you move to the next stop. At some point of the continued use of this process the water will come out clear with only suds.

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Ohhh, I like that idea, but would that mess up a septic system??? So many of the parks are not hooked to city sewer.