I'm getting the well system in my home back in working order and
breaking it off the household feed for use as outside water sources and
I have an existing pressure tank that I can use, 36 gallon Sears
390.29161 - I need to test the air bladder which I'm in the process of
In the event that I've got the same air pressure in the morning that I
had when I refilled the air I'll need to know the PSI that the bladder
should be filled to while OFF SYSTEM and no water in the tank.
Anyone have any ideas how much pressure should be in them?
I'm hoping to not have to replace the tank and to avoid that expense and
to only have to work on a new jet pump. Replacing both would double the
As for the pump, I'll be using a 1/2HP convertible jet pump. Pretty
standard stuff and the lowest HP I seem to be able to get. I really
shouldn't need more than 10GPM at any given time.
BTW, irrigation would be a drip system covering the flower beds and
possibly a small veg garden, just in case you're wondering.
Alot of rambling for a little question (how much pressure in the air
bladder, that is) but I figured I'd explain what my needs are and what
I'm doing just in case anyone wanted to kick further input.
With the tank empty, you want to set the pressure to be a tad less then your
pump cut in pressure. In my case, I have it set to 24psi, and my pressure
regulator cuts in at 25. You don't want the bladder pressure to be higher
then the pump cut in pressure, because if it is, then when the bladder hits
the bottom, you will have a sudden loss of pressure before the pump kicks
in. The resulting surge can jar your pipes, though in most cases it doesn't
Sometimes when I hear out a question and its end purpose, I like to start
from the purpose.
I can't see all you're doing for doing drip irrigation on a flower bed and a
small garden. Won't be anywhere near 10 GPM. The current pump and
reservoir tank should easily handle that and the house needs. Seems to do
fine here without all the aids you seem to need. No drip, manual surface
Find interesting the air pressure thing. My reservoir tank relies on the
elasticity of the bladder for pressure when the pump is not running. Also
aiding is the pumphouse is uphill from the house and rest of my irrigated
area. Maybe you're pumping uphill to the flower bed etc. But, should be of
little consequence since the flow rate is so small.
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
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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