I have a pressure tank in my garage which is, of course, connected to a tee
with the gauge and switch located very close to it. I would like to leave
the gauge & switch where they are but extend the 1" line going to the tank
about 70 feet. This would allow me to place the tank under my house in an
area where the "crawl" is about 9 feet high.
Is there any reason not to have the pressure tank so far from the switch?
I would also like to insulate the tank so it will not sweat during our hot,
very humid summers. What would be the best material for this? I do not
want to harbor mold so I would like to keep air from getting between the
insulation and the tank.
Many thanks for any help.
Oh....this is water pressure tank. I was thinking air compressor when I
Don't see any problem w/ the distance re: switch.
As for insulation, unless you use spray-on expanding foam my best "what"
would probably be a (or two, depending on size) water heater blanket
salted to taste.
I would imagine that you could end up with the switch cycleing of-on-off at the
end of a cycle because the presure at the pump drops after the pump turns off
because water pressure is higher at the pump switch than at the tank until the
pump turns off. Then the pressure drops to the tank pressure. Larger pipe to the
tank, larger on/off pressure difference, or a separate small pipe back from the
tank to the switch could alleviate this possibility. This is all hypothetical. I
haven't done it.
I haven't, either, but 70-ft of 1" didn't seem out of sight for a
pressure drop but I'd surely agree larger would be make for less.
Well, let's just go look at Crane handbook...
For Sch 40, dP (psi)/100-ft vs flow rate is
2 0.2 0.04
3 0.3 0.09
4 0.5 0.15
5 0.8 0.22
6 1.2 0.3
8 2.0 0.5
10 3.0 0.8
15 6.4 1.6
20 11.0 2.8
Assuming plastic instead of steel will be somewhat less; I don't have
data at hand to show just how much. A 70-ft run instead of 100 is
probably about a wash when add a fitting/elbow or two.
Unless he has a sizable well capacity, it would seem the 1" would
probably be enough but certainly the reduction in losses by going up to
1-1/4" are sizable. Amazing what a little r-square can do when r>1
isn't it??? :)
On Sat, 05 Jun 2010 12:02:06 -0400, email@example.com wrote:
I don't like Harbor Mold either, even though Harbor Freight seems
AFAIK, mold requires something to eat, and won't grown just anywhere,
even if it is wet and dark. And it can't eat fiberglass, so a water
heater blanket sounds fine to me too.
When I have had mold it's been on sheetrock, and when I've had mildew
it was on a thermal blanket of mine that my idiot roommate found in
the closet and used to soak up dribbling from the steam radiator, and
then just left there for weeks.
(BTW, the blanket smelled disgusting, and I washed it in a machine and
it smelled just as bad afterwards. Then I dried it in a dryer, not
even especially hot, and it smelled just fine after that. Never even a
trace of the bad smell for years after that. Thoough a portion of the
brown blanket was now white.
I would suggest you run tubing back to the pressure switch.
Since it's easier to run wire than tubing, you might just re-locate the
pressure switch at the tank. You can "do the math" and run the
appropriately sized wire, or you can just place a "contactor" at the pump or
near the well head such that the pressure switch would only operate the
contactor (a fraction of an amp) rather than the pump (10 to 20 amps.)
It's best to have the pressure switch on a separate connection to the tank.
If you have to use a "T" then use a "T" on the outlet side of the pump.
When no water is being drawn it will read true pressure. If water is being
drawn it will tend to "see" a lower pressure which will cause the pump to
come on a bit sooner.
In industrial plants, pressure sensors are often connected to
"instrumentation" tubes. The tubes are run to the process being monitored.
You would have to find some way of spraying insultation onto the tank. Any
place where moist air can find it's way to the tank will cause local
The pump cannot run continuously because (1) it requires cooling via the
water flowing through it and we're not using water all the time, and (2)
We're not rich enough to pay the elec bill.
Thus the pump must be on a pressure switch. When we use water the pressure
in the line drops and the pump kicks on. Without a pressure tank, the pump
would turn on & within a second the pressure would go up enough to turn it
off. A secone later the pressure would drop enough to turn it on again.
Rapid cycling will destroy the pump.
The pressure tank allows a good bit of water to be used before the pressure
drops enough to turn the pump on. Then it stays on long enough to refill
the tank. The bigger the tank, the less frequently it cycles.
On Mon, 7 Jun 2010 07:59:19 -0400, "Stormin Mormon"
Now we're getting some where. You're talking about some kind of
pressure tank, for a pumped water system? Now, is this a residence,
business, camper, remote fire fighting operation, or what? Sure helps
if you provide more complete information.
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