Python No-spill (backflow Prevention?)

[allieharicot]

I just purchased a Python No-Spill from petsolutions.com. My dad took a look at it and is thinking that it is unsafe and if the pressure adjusts from the sink in any way, we will contaminate our drinking water in the sink with backflow. I searched high and low on the internet, and through these forums, not finding an answer.

I did find an item called a "check valve". Would this do the trick to prevent backflow into our faucet? I'd rather not drink fish poop. Is it possible to hook up one of these valves to a standard faucet?

Thanks to anybody who knows anything about this subject at all.

 

[england]

ive never used these but would not imagine for a second it would contaminate your water supply
ive had swallowed many times mouthfuls of tank water and iam still alive actually just pinched myself to check....yep iam alive

 

[allieharicot]

ive never used these but would not imagine for a second it would contaminate your water supply
ive had swallowed many times mouthfuls of tank water and iam still alive actually just pinched myself to check....yep iam alive

Even still, as long as I live under my parent's roof, I have to be 100% sure there is no chance of backflow before I can even hook it up, or I have to send it back. (Which I do not prefer.) My dad taught a class on hydrolics subbing for my Grandpa's class a long while ago, and if he feels it is risky, I trust that. So I'm going to assume there is a risk of backflow unless somebody else has done research and can explain why not. Thanks for replying so soon though! And the humor is fun. haha

 

[Inchworm]

Hi allieharicot

I've been a moderator on this forum for around 5 years, and have read an awful lot of threads in that time, but I've never heard of anything like that happening.

I use one myself and can't imagine the water pressure dropping so low that it would do that. But then, I'm using city water and the pressure is good. Are you getting your water from a well that doesn't pump to fast?

 

[Tolak]

Water follows the laws of gravity. If you were working on your tank, with the faucet lower than the tank, and the water pressure suddenly went to zero, it would siphon out the bottom of the faucet adapter if you were draining, not defy gravity & go upwards.

For filling keep the output of the python above the water surface if the faucet is lower than the tank surface. If the faucet is higher than the tank surface water will not defy gravity & go upwards, if that is the case there is no worry no matter what the situation.

The bore of the python hose is way to large to involve capillary action.

 

[greenbottle]

for backflow to occur the pressure in your drinking water system would have to be less than that of the waste water coming from the tank.

as most drinking water is supplied at a good high pressure there would have to be a major fault which would effectivly cause a vaccumme (spelling!) in the drinking water system to allow backflow to occur.

as a scientist i can say that as long as your drinking water flows at a good normal pressure (even just gravity driven) this will not happen. Any pressure which is sufficient to cause a backflow would cause the python system to fail (i.e. break and send water everywhere!- this could not even happen as the syste is not sealed).

 

[Schmill]

Agree with the above, for the backflow to occur you would have to be filling the tank, (for the faucet to even be open), and the syhphon pressure from the tank would have to exceed the water pressure in the faucet. The only condition I could see this happening would be if you are on incredibly low water pressure from a well or something that suddenly dropped to zero, or else if there was an actual fault with the mains water supply, again causing pressure to drop to zero.

Still, all the above only confirms what has been written above. As you supposed in your initial post, if you REALLY want to be sure that it's even less likely to happen you could fit a checkvalve between the faucet and the python, but it's pretty much uneeded.

 

[allieharicot]

Agree with the above, for the backflow to occur you would have to be filling the tank, (for the faucet to even be open), and the syhphon pressure from the tank would have to exceed the water pressure in the faucet. The only condition I could see this happening would be if you are on incredibly low water pressure from a well or something that suddenly dropped to zero, or else if there was an actual fault with the mains water supply, again causing pressure to drop to zero.

Still, all the above only confirms what has been written above. As you supposed in your initial post, if you REALLY want to be sure that it's even less likely to happen you could fit a checkvalve between the faucet and the python, but it's pretty much uneeded.

I think a checkvalve would make my father more comfortable with my using the sytem. What size would you recommend for the python? If anybody flushes the toilet in our house while I'm using it, the pressure drops to next to nothing, so that does impose a threat after reading the above. We have good city water pressure, just not with multiple items at once on the same level of the house. We can have our dishwasher and clothes washer go at the same time as they are on different levels and I think it stays about the same, but just not when anybody flushes or uses one of the other sinks in the bathroom upstairs, on the floor the tank is. Thanks everybody for your input!

 

[Paavn]

unless you have the python somehow connected to the bottom of the tank, there's not nearly enough water pressure for the water to back flow, i cant even get the python to drain my tank unless my water faucet is running.

and if you think the water has back flowed into the faucet just let the water run for a little bit and its all flushed.

 

[Duck1976]

For yor water to flow into your drinkiing water (ie back up the tap) it would basically have to flow against nature (fluid dynamics & gravity) and would be being sucked into the tap (ie through a vacuum etc..).

If this were happening in your house I'd be more worried about the internal plumbing than putting a check valve on the python.

 

[Schmill]

I think this is more a case of satisfying 'dad' with a checkvalve, than it is convincing the OP about the science and dynamics involved.
We've all had these discussions, no matter what you say to your Dad, whatever figures, scientific facts & reasoning you use, they won't be happy unless you do it their way.

A checkvalve is 99.99% not needed unless the water pressure goes negative, (ie. the tap starts sucking), but if fitting a checkvalve will mean that the OP's Dad gives them the green light to use the python, then thats the answer