Replies

1. 
   MarkH | Jul 31, 2011 10:17pm | #1

   I would replace the guts on the toilet, because it is malfunctioning.  As I understand, the fill valve in the toilet empties into a standpipe, and cannot draw water from the toilet tank.  So they do have a vacuum break on the toilet.  I don't understand how yours is drawing water from the tank, but it won't hurt to change the valve.

1. 
   DanH | Jul 31, 2011 10:27pm | #2

   Yeah, pretty sure that current code requires some form of backflow prevention in a toilet tank fill valve.  Wasn't always true 30-40 years ago, but replacing the fill valve with a modern unit should fix the problem.  Fluidmaster makes a good (and cheap) replacement unit.

1. 
   DoRight | Aug 01, 2011 09:36am | #3

   Many thanks to Mark and Dan

   Thank you.

   I figured that would be the case.

2. 
   rdesigns | Aug 01, 2011 05:19pm | #4

   Does your toilet have a submerged fill valve? They were sold as a replacement fill valve about 10 or 15 years ago, and may still be sold in some places.

   They do not have a float valve; they work by shutting off the flow when the level of the tank water above them creates enough pressure to close the diaphragm that shuts off the water. They are illegal in every code I know of, and would allow the siphonage you desribe.

   The normal, legal type of ball cock, or float valve, has its outlet located up above the water line so that the only time the valve opens is when the water level drops enough to let the float device drop, which in turn allows the valve to open. This means that lowered level of water is not high enough to be sucked back into the piping system via the fill valve because it is always located above the water leve.. So, in answer to your question--no, toilet fill valves do not have some kind of backwater preventer added to them. The way they are made precludes the possibility.

   However, Fluidmaster and some other manufacturers do make an adjustable-height ballcock whose height can be raised or lowered according the depth of the tank. If someone installed one these in your toilet, but did not extend the height so that the filler valve is above the water level of the tank, then it could be submerged and thus allow tank water to be sucked back in under the wrong condidtions.

3. 
   [email protected] | Aug 05, 2011 07:05pm | #5

   Why the pump?

   I'm not sure that replacing the float valve is going to work.  The new valve that is desinged to prevent back flow by kkeping the outlets above the water level in the tank, just might let air in and cause the pump to cavitate.  You may need to install an actuall backflow valve in the line to the tank to keep that from happening. 

   If you are going to keep the pump, you might want to plumb it so it feeds the house and the sprinkler system.  You just need to be sure the discharge pressure is below 80-psi. 

   I think you should check into why the pump is there.  My thirty year old house had a similar setup when I bought it.  The static pressure from the meter is 85-psi.  Run a sprinkler with out the pump and it dropped to about 15-psi. 

   I undid the plumbling to get at the 1-inch galvanized steel pipe that feeds the house.  I found that the interior had rusted enough that I couldn't insert my little finger in the end.  So the actual diameter was about 3/8-inch and the friction factor was huge.  Since there was about 125-feet of line between there and the meter, there was no way to maintain pressure to run the sprinkler without a booster pump.  But that isn't really the right solution. 

   I ended up running a new 1-inch pex line to the house from the meter.  The sprinklers now work without the booster pump.  The pressure drops to about 65-psi with every faucet and hose bib wide open.