Pump Tank Siphon Systems

12 volt and manual pumps

I have been experimenting with several pump types to use in conjunction with the pump tank accessory. The pump tank accessory, to review, is a reservoir that holds the urine until it can be pumped out to a holding tank. The pump tank isn’t necessary in situations where gravity feed will empty the tank, that is situations where the holding tank or drain field is below the toilet all the time. There are a few situations where the holding tank or drain field sits above the toilet or where the drain line must clear a hurdle that is above the toilet. Most sailboats have the holding tank mounted higher than the toilet because they don’t have room in the bilge. Also, Granny in the basement installations and most below-ground prepper bunkers will need to pump the urine uphill. In those cases, the pump tank is a good accessory to have. The pump system can be manual or electric.

Originally, I experimented with a reciprocating, hand operated, transfer pump to move the urine out of the pump tank. I started with a cheap Harbor Freight hand transfer pump and soon discovered that they didn’t last long enough to make them practical. I moved up to a more expensive commercial hand transfer pump and the jury is still out on it. I simply haven’t used it enough to judge, but I don’t rule it out. So far the leading contender for hand pumps is the Sierra Premium Primer Bulb.

It is made from a plastic that is supposed to be impervious to odor transfer, being designed for gasoline. That was my major concern for using anything rubber or plastic – that it would absorb and transfer the smell of the urine over time. Most plastic hoses do. But even if that is the case over time, they can be replaced with little expense or effort. It has a built-in check valve and it has also gotten good reviews everywhere I have viewed it. It’s biggest downside is that it is ugly and many people don’t want to operate a hand pump after using the toilet. If you are arthritic they can be difficuly to squeeze. It could be installed in a small housing and a lever attached that would compress the bulb with less effort. That would resemble more closely what the common marine head looks like. I am still working on that so look for another article soon. I will link it when it is finished.

But if you want to simply press a button and have modern technology drain the pump tank for you, here is how you do it. You will need the items below, specifically a 12 volt or 110 volt fuel pump depending on the power source. You will need plastic tubing which can be vinyl hose or black fuel line hose if you don’t want to see if things are moving along. You will need a “horn” or “momentary” button and you will need the reducers necessary to attach the tubing/hose to the fitting on the holding tank. The nipple on the pump tank fitting is a 3/8-inch barb fitting. I suggest using the same diameter barb with the fuel tank to simplify things. You can use a compression ring hose clamp or a screw type hose clamp. They usually are located next to the tubing at the store. I will show you how to make a wire hose clamp using only pliers in this article (here).

When you put it all together it should look like this.

If you are wanting to use 110 volt the simplest thing to do is to buy a 110 volt fuel pump. Consult a licensed electrician before installing it. I guess I have to say that.

When all that is done, you can use the toilet a few times before having to empty it but tell guests to flush it each time or you will overflow it for sure. It is also good to rinse the line with a small amount of water to help reduce the buildup of scale. You can use vinegar to flush the line and that should help. Look for more articles on this topic in the future. It has a lot of possibilities and I encourage you to post your installations along with any issues you had or spectacular successes. Especially the spectacular successes. Please feel free to make constructive comments or ask questions below.

Copyright 2019 – C-Head LLC – All rights reserved on all content.

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