Waste pipe entry into grey tank!

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joncar
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Waste pipe entry into grey tank!

Postby joncar » Tue Oct 20, 2015 2:31 pm

I have struck a problem with the routing of my 32mm waste pipe under the floor, with only one way that I can follow - owing to all of the necessary workings one runs into (mechanical etc)!
I have a 122 litre fresh water tank inside the m/home and am planning having the grey tank - same size, underneath where the spare wheel was located. I was planning on having the inlet on top of the tank, however this is not possible, so would have to go as close to the top (as 'Spinweld' will permit) on the side wall. The depth of the tank is 275 mm, so am not able to lower the tank (90 mm packer) to take the 90º bend as it would be too close to the ground - approx 210 mm. (300 mm when attached to the underside of the chassis with side entry).
I have been told that it is ok to enter on the side - as above, even with same capacity tanks, as the water will only settle along the waste pipe as the tank fills. The reason was explained to me, however I lost the plot along the way. The total run from shower waste to tank is approx 4 m. The only real fall will be at the shower waste - approx 200mm @ 45º where the Hepco valve will be located.
One solution I have is to buy another tank with a smaller depth. I have one in sight @ 200 mm x 1500 long (140 L) but it does not have a baffle.

Would appreciate any feedback, thanks.

John

beanpole
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Re: Waste pipe entry into grey tank!

Postby beanpole » Tue Oct 20, 2015 9:03 pm

Water will find its own level so an inlet to the tank can be in from the side as long as the tank vent is at the highest point.
It may be a bit slow draining when the tank is nearly full but this will depend on the vent size as well.
Always come in from the side, never from the front as the sloshing of the waste when braking will occasionally force its way back up the pipe and with a HepVo it could collapse the diaphragm back into itself. With a water seal it has the potential to push waste back into the appliance.
As you have a 200 m fall from the shower at the front of the pipework, there should be no major problems.
Gordon

joncar
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Re: Waste pipe entry into grey tank!

Postby joncar » Tue Oct 20, 2015 9:43 pm

Thanks Gordon.
I can now proceed with confidence. :D I take in what you say about having the inlet on the side too.

John

joncar
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Re: Waste pipe entry into grey tank!

Postby joncar » Wed Nov 25, 2015 9:37 am

Have now finished installing the grey tank (122 l) and waste pipes (32mm) - as far as I can go for now. All ready to hook up to sink and shower. Did a test run on time to empty the tank and was surprised it took only 3 min :o I then realized that the MH was up on blocks (100mm) on the discharge side, so still some water left in tank - wouldn't be much though. Allowing for that I would say less than 4 minutes to totally empty.

John

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Karmann57
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Re: Waste pipe entry into grey tank!

Postby Karmann57 » Wed Nov 25, 2015 11:06 am

You must have a small drain hose? My 100mm waste hose empties the 100 litre grey tank in about 15 seconds :TU
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joncar
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Re: Waste pipe entry into grey tank!

Postby joncar » Wed Nov 25, 2015 12:53 pm

Wow, that's quick.
My waste hose is only 32mm. Quiet a difference between 100 and 32 mm!
Still I don't think I'm going to upset the person waiting behind me...

John

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idex
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Re: Waste pipe entry into grey tank!

Postby idex » Wed Nov 25, 2015 2:02 pm

4 mins is not too bad. We've been stuck at dump stations behind European and British vans with 1" hoses taking around 20 mins to empty. I suspect they may have had blocked vents also, since we can empty our 70 litre tank via a 1/2" garden hose quicker than that. Normally it takes about 10 sec using our regular 3" hose.
Bruce


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