Installing Vacu-flush

Hey there. I suspect I know the answer to the following question - but just a quick check before I start work on the installation ....

I am replacing my Raritan Crown head with a Vacuflush in the forward stateroom (I know some of you will disagree with this - but I have my reasons). I am just wondering whether you think it is necessary to install a vented loop in the system?

I suspect the answer is yes, and the place to put it is between the through-hull and the holding tank evacuation pump, but honestly I am wondering if it is really necessary. Given the pump and all the valves (all of which will stop back-flow if functioning correctly), I think there is very little chance of water coming back in - so I am really protecting against a leak around the vicinity of the evacuation pump (possible - but only a bit more possible than a hose leak around the vicinity of the through-hull). Also - I hate to think of the cr*p sitting in the hose between the holding tank evacuation pump and the top of the vented loop.

Regardless, unless everyone tells me there is really no need, I think I will put one in. Better safe than sorry.

Let me know what you think - and whether (and where) you have them on your vacu-flush system.

Thanks!

Murray

If I read this correctly, you are talking about the the overboard discharge pump.

In my set-up, I used a Sealand T series pump. I plumbed from the holding tank to a thru-hull previously used as overboard discharge for the old head system. I did not use a vented loop. I have had no problems, but I only open that thru-hull when I am actually going to pump the holding tank overboard. The rest of the time I keep it closed.

Since the bowl uses fresh water and the system needs to build vacuum, there obviously wouldn't be one in the system prior to the holding tank.

Quote:

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Originally Posted by hattitude

If I read this correctly, you are talking about the the overboard discharge pump.

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Indeed - that is what I meant by holding tank evacuation pump.

Thanks - Murray

I installed a VF in my Krogen and followed the installations instructions and there was no mention of a vented loop. My present system on my Hat has none either. Ron

A vented loop is required when the discharge end is underwater....like in the discharge line from a toilet overboard...if the overboard discharge is at the water line, no real need for a vented loop...

i have a vented loop between the Sealand overboard discharge and the thru hull but i dont' think it's needed.

although i wonder if water could make it back past the bellows and duckbills of the pump, especailly since the T series pump only has one pair of DB, vs the two pairs on the standard vac pump.

it's good practice to close the seacock anyway, as long as it's accessible... and if you dont' have a key switch on the overboard pump, it must be closed to be legal.

now with a impeller macerator, i think a vented loop is a must if you're discharging under WL.