Posted by Scott Hildenbrand on September 29, 2007, 11:53 am
Ook wrote:
<S>
>
> Are you sure it's bladder elasticity, and not air pressure behind the
> bladder, that is giving you pressure? A bladder can't hold pressure - it
> would burst. Bladder tanks rely on the air behind the bladder, not the
> elasticity of the bladder, to maintain pressure when the pump is off.
>
> I irrigate a 1/3 acre garden and yard with a small pump. The problem with
> 1/2 horse pumps, especially the cheap ones, is that one day you decide that
> drip irrigation won't work for some odd patch of garden, and you go and hook
> up a couple of impact sprinklers. That is when you find that your 10GPM pump
> only pumps 10GPM at ideal conditions that don't exist in the real world. And
> having been through several different 1/2 horse pumps, I can testify that
> they are not all equal. My Gould JRS5 is an excellent pump. I also have an
> el-cheapo Flowtec that I got from Home Depot that is a worthless piece of
> junk. Today, I use a Star 3/4 horse pump. I don't need the theoritical
> volume it can pump, but the difference between the smaller pump and the
> bigger pump is that it takes 30 seconds for the big pump to fill the tank
> and bring the system up to pressure, where the 1/2 horse pump took a couple
> of minutes. Also, the Star maintains volume at 55psi, where most cheap 1/2
> horse pumps barely trickle at higher pressures. You put them under load, and
> the small pump runs constantly, and the big pump cycles at a comfortable
> rate.
>
> </soapbox>
Your soap box may have just talked me up to the 3/4. Granted I'll be
using it to water stuff for the most part, but there will be a need to
do more from time to time.
At the very least I'll check elsewhere for a pump than at Lowes.
Oh, and some pressure tanks that use a diaphragm are indeed
pre-pressurized from the factory to specs. They don't have any way
however to re charge the tank and fill the other end with air.
Posted by Ook on September 29, 2007, 1:28 pm
> Your soap box may have just talked me up to the 3/4. Granted I'll be using
> it to water stuff for the most part, but there will be a need to do more
> from time to time.
> At the very least I'll check elsewhere for a pump than at Lowes.
> Oh, and some pressure tanks that use a diaphragm are indeed
> pre-pressurized from the factory to specs. They don't have any way however
> to re charge the tank and fill the other end with air.
Heh - I understated how much I love my 3/4 pump! When that bad boy kicks in,
it's quieter then then my 1/2 horse pumps (go figure?), and the pressure
ziiipppss right up to cut off. That was the first different, and it was
immediately obvious. The 3/4 zips right up to cutoff, while the 1/2 runs and
runs and runs. The Star pump maintains high volume at higher pressure, so it
fills the tank up much faster. The other pumps loose most of their volume at
higher pressure, which is why it takes them so much longer to fill the tank.
It's a Star Systems 3/4 pump - I looked up the specs online, and it compared
close to the Goulds, and was way ahead of the Flowtec. The Flowtec pumps are
cheap bottom end pieces of junk. Avoid at all costs. Goulds are very good,
and have the highest capacities of all of the ones I looked at. The Star was
a somewhat close second place. IIRC, the Goulds 1/2 horse pumps more then
the Flowtec 3/4 horse. I bought it at Coastal Farm supply. Home Depot and
Lowes here only carry the cheap low end junk pumps.
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> Are you sure it's bladder elasticity, and not air pressure behind the
> bladder, that is giving you pressure? A bladder can't hold pressure - it
> would burst. Bladder tanks rely on the air behind the bladder, not the
> elasticity of the bladder, to maintain pressure when the pump is off.
>
> I irrigate a 1/3 acre garden and yard with a small pump. The problem with
> 1/2 horse pumps, especially the cheap ones, is that one day you decide that
> drip irrigation won't work for some odd patch of garden, and you go and hook
> up a couple of impact sprinklers. That is when you find that your 10GPM pump
> only pumps 10GPM at ideal conditions that don't exist in the real world. And
> having been through several different 1/2 horse pumps, I can testify that
> they are not all equal. My Gould JRS5 is an excellent pump. I also have an
> el-cheapo Flowtec that I got from Home Depot that is a worthless piece of
> junk. Today, I use a Star 3/4 horse pump. I don't need the theoritical
> volume it can pump, but the difference between the smaller pump and the
> bigger pump is that it takes 30 seconds for the big pump to fill the tank
> and bring the system up to pressure, where the 1/2 horse pump took a couple
> of minutes. Also, the Star maintains volume at 55psi, where most cheap 1/2
> horse pumps barely trickle at higher pressures. You put them under load, and
> the small pump runs constantly, and the big pump cycles at a comfortable
> rate.
>
> </soapbox>