In my basement I have a sump pump that pumps up about 6 feet to the
outside away from the house. That pump does not have a back flow value
which has caused me no problems. Any water flowing back has been less than
a gallon. During the worst rains the pump operates for 40 sec every 15
I just purchsed a Watchdog battery operated backup sump pump that I am
getting ready to install. I will be tapping into the existing outflow
line which is a 1 1/4\" PVC. QUESTION: I purchased two back flow valves
to put in but do I really need to install any?? I am concerned with water
standing in the line durning the months that the pump isn't used and also
concerned with it freezing during the cold days durning the end of winter
and beginning of spring.
Any help you can provide would be greatly appreciated.
Thanks in advance.
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I'm also using an electric sump pump without a check valve and never had
any problem either. In my case the water head is 8', then it drops
vertically 4' on the other side of the wall and then slopes 4'+ more
towards the end of the pipe. In my case I think the 4' drop is enough of
backflow prevention. It is not a sealed connection on the other side, so I
think I'm pretty safe from the water siphoning back in case the end of
the pipe ever gets submerged into a freaky high flood waters.
In any case, the amount of water that comes back is slightly more than you
estimate. Just by doing math on the size of the pipe, 1-1/4\" pipe holds
approx 1.5 gallons of water in 6' length. But if your sump basin is large
enough, it won't be a problem. Depending on how your discharge pipes are
laid out, freezing may or may not be a problem (in my case all the pipes
outside are lower than the highest point, so there is never any water in
pipes on the outside) but I think that the valve is not even sealed
enough to prevent all that water from seeping back into the basin anyhow,
especially when the pump only fires occasionally. Yet it adds resistance
to the water. It's also another part to fail or get clogged.
I've never seen the check valve to be REQUIRED. There are some backup
prevention requirements for sump pumps operated by the drinking water
pressure (read about these, never saw them) but they're talking about the
drinking water backup for obvious reasons, not the sump pump discharge
If anyone else knows a very good reason to have the check valve installed,
I'd love to hear that as well. Just like yourself, I have a valve sitting
on a shelf, it's just never been installed.
Well, I do have a battery backup but it protects a secondary, smaller pump
that's set about 8\" higher and has its own switch. The secondary pump
has no check valve either, at least I can't see it on the outside
(although it can be built into the pump, I think), it makes me wonder how
this system even works because they both discharge into the same pipe and
at least one pump would have to have a valve else all the water would just
come right back through the other pump. Maybe when the main pump gets
going, the water is just flying straight past the \"T\" and most of it
reaches the discharge while only some of it returns through the secondary
pump. I'll have to revisit all this, now I'm glad I took part in this
discussion else I would not have looked more carefully. Come to think of
it, it does take a rather long time for the main pump to empty the basin,
maybe this secondary pump business is just messing things up.
Since I have not set this system up (came with the house), I think the
reasoning was that the 3/4hp secondary pump would last twice as long on
the battery backup as the 1.5Hp main pump and it won't fire for a few
more minutes (until the basin fills 8 more inches) in hopes that power
will come back up sooner. In fairness, all blackouts have been very
temporary so far - nothing longer than a few minutes. What was the reason
behind not using check valves despite there being two pumps - that I
can't tell and I'm now thoroughly confused about the matter myself :)
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