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Re: Size and number of duck bills
Posted: February 17th, 2021, 8:50 pm
by Viper
Ya the VG4 is the J style pump that takes 2" valves. The VG2 is the pump we're all used to seeing more of (S series) which takes the 1-1/2" valves. Depending on the setup, the S series might be mounted on top of the tank or completely separate of the tank. The J series would always be mounted to the tank as it becomes an integral part of it.
Re: Size and number of duck bills
Posted: February 18th, 2021, 5:07 pm
by tgebler
Thanks. You are clearly the marine sanitation guru on this site. I have learned alot.
Re: Size and number of duck bills
Posted: February 18th, 2021, 7:00 pm
by Viper
No I stink at that

Re: Size and number of duck bills
Posted: February 19th, 2021, 4:53 am
by thatchh
I have a 2004 396 aft cabin. My two vacuflush pumps have small tanks separate from the main holding tanks, and they each take 4 1 1/2" duckbills. There should be no other pumps, unless you have overboard discharge pumps. Those would not affect your toilet flushing as previously stated. I have added a couple of pictures of my pumps in case it jogs your memory. They are the same for and aft. The forward pic is not very clear. I was actually taking a picture of something else at the time. It's possible if you have your Carver manual with the bill of materials, that it might tell you what units you have. There is a separate list in my manual for items with serial numbers.
Re: Size and number of duck bills
Posted: February 19th, 2021, 9:40 am
by tgebler
Thanks, I have ordered the valves and will give it a go when the weather gets warmer. I figure sicne it is a dirty job, I may as well make all the changes at one time. I do have two discharge pumps.
Re: Size and number of duck bills
Posted: February 19th, 2021, 10:03 am
by Viper
Remember you're working with bio hazardous waste, it can be dangerous. Put on a couple of layers of good nitrile gloves and you should be wearing full face protection in case anything sprays out while you're doing this, which can happen under certain conditions. Have a ton of rags on hand and a bucket or bag to put them in. Spread a bunch of rags under the fittings before you undo them. Unthread the fittings slowly to release any pressure that might be there and allow any vacuum to equalize to atmosphere. There shouldn't be too much in there when you open it up unless there's a problem but it pays to be prepared.
I lightly lubricate the base of the valves so they slide a bit when you're tightening the fittings back together. I find that if you install them dry, they catch and twist inside the fitting. This causes them to distort and open up which will cause the system to leak. When that happens, you'll think that since you just replaced the valves the leak must be elsewhere and spend an eternity trying to find one that doesn't exist. Dish soap works fine.
Oh and don't forget a clothes pin.....for your nose
Good luck
Re: Size and number of duck bills
Posted: February 19th, 2021, 11:18 am
by tgebler
Thanks!!