black tank flush question

[SMellard]

Great information. at least I know where I can start looking.

Thank you

[Hoopy Frood]

Would/could there typically be a limited amount of leakage until the unit seals under a higher pressure?

Yes, but if it leaks, it's time to replace it when possible. It won't cure itself. The OEM units are usually plastic and pretty low quality.

[Rabbit]

This type vacuum breaker should seal with very little pressure. Even then it’s normal to get a few drops of water out of it. The higher the pressure it takes to seal, the more water will escape, to the point of squirting out.

[Second Chance]

Great information. at least I know where I can start looking.

Thank you

@SMellard -

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Rob

[jbailey]

Florida2022 - The tech is correct, all trailers that have a plumbed black tank flush have some sort of check valve, either at the tank or eleveated above the tank and black tank flush hookup depending on type of valve. My personal expeirience in my years caming is that I have NEVER had seweage back up to the valve or past it.

What does amaze me is what people do with the hoses they connect to the dump site water spicket. Hoses in toilets, hoses in sewage hoses, dropped on the ground, and all sorts of crazy unsaitary activity. Therfore the safest course of action is to set the expecation to have a seperate and distint fresh and flush hoses to eliminate potential contamination.

Ben

Hi all, I'm new here. Just purchased a Grand design BHS367 in July 2022, and took it out for my first winter camp in October 2022. My issue is with the process used for the Black Tank Flush by a technician I had recently hired to help, as I don't know what I'm doing at all. I was greatly disappointed to read the Manual Later, which was also stated in this thread above by trailrydr , that retyped exactly what the manual states:

Sewer Tank Flusher Steps:
1. Connecting the sewer hose and attaching a garden hose –
not your fresh water hose – to the sewer tank inlet (see
photo).
2. Open the water supply to full pressure to flush tank.
3. When the water runs clear from the sewer hose, shut off
the water supply and disconnect the garden hose from the
water source.

When the technician performed this part, he used my heated fresh water hose, which cost quite a bit. I asked if that was the method, and he said that these units are built with a safety feature that will prevent black water coming back out through the inlet, he said the there's a trap pipe that is at a much higher elevation than the black tank, to prevent the black water from coming back out and getting into my fresh water hose.

My question is does anyone else know this to be true, I'm afraid to continue to use my fresh water hose after this procedure was done.

Thank you,
Florida