He's talking about evaporative cooling units . They pump water from a sump
at the bottom over a fiber pad , then suck air thru same pad to cool by
evaporation . Most units will have 3 pads and the outlet on the 4th side .
Better ones will have a float valve to maintain water level in the sump .
What Steve is talking about is a device that drains the sump daily , which
probably helps keep mineral deposits out of the pump and off the pads .
FWIW Steve , you can probably use a light timer to actuate a solenoid
daily and save a wad of money . Use dual relays and a dashpot delay on the
end of cycle to let the supply water run a minute or two to rinse the sump
before the drain valve closes .
I can't say about those devices but my experience with using re
circulating pumps on swamp coolers compared to just running the water
thru once and out to the lawn is that recirulating the water is VERY
hard on the cooler causing a lot of corrosion and gunk build up, far
in excess of what you get running the water thru only once. I also
had a water cooled outside AC Condenser that bleed off water when
running to try and keep the salt buildup from being as bad. It still
built up a ton of crap. For $40 I'd do it as it will surely be better
then not doing it.
Well exxxccuuuuuUUUuuuse me ! I didn't know , and the way your question was
worded ... Anyway , I grew up out there , a bit north of "y'all" near
Potato Country . The biggest thing I don't much like about The South is the
humidity . Swampers don't work well in 90% RH ...
And I'm betting that Steve's device is just a timer-actuated dump valve ,
probably tied to an inlet cutoff . Hmmm, I wonder if a sensor could be
rigged up to dump when a certain concentration/threshold of precipitable
compounds is reached . Probably be easy to program for someone into that
level of computing .
I think it might be worth it. And where do you live?
I think the minerals will still build up on the pads. I had a unit in an
apartment. I did a little maintenance on it once in the 5 years I lived
there. I don't even think I shut the water off. It went to 17 degrees once.
That was in the high desert of ca. Low desert gets hotter. It brought down
the temp 20-25 degreesm with 20 % humidity with a small unit. Here in
Pittsburgh it's not going to work, but they still use misters on fans in
sports and in some open buildings.
I think what Steve is talking about is a dump valve to drain the water
from the sump . Might help slow down mineral buildup on the pads and in the
Tater country , heh . I grew up about 25 miles from the Utah/Idaho state
line in Box Elder county and the average humidity up there is more like
25-30% , swampers work great . Idaho is famous for it's Russet potatoes ...
You're not confused , I did live on the east side of the river or many
years , but we've moved . We now reside in a clearing in the woods in Stone
County Arkansas . I'm retired now , and run the machine shop part time on
whatever comes thru the door . I do manage to stay busy with the garden ,
chickens , orchard , and building a house .
More water efficient than the traditional bleed valve that drains continuously.
Since swamp coolers are typically run in regions where drought is a concern,
they may be somewhat useful in reducing water use. Not convinced either solution
will prevent scale buildup. Just do a good job cleaning after each season.
Once a day, they dump the entire tray of water, and reduce the buildup
of minerals in the water, hence, the pads don't mineralize as fast, and
the ph of the whole thing is altered so that the metal corrosion is
reduced. I still am placing an anode in there.
On Thursday, June 5, 2014 1:28:39 PM UTC-7, SteveB wrote:
I live in Phoenix, where the water can be very hard, and
I don't think dump valves help. What helps is having the
swamp cooler made out of stainless steel, fiberglass, or
plastic, but I think all blower impellers are made of
Remember the evaporative cooling index, which shows how
cool a swamp cooler can make the air, for any given
combination of outdoor temperature and humidity. They
don't work very well above 20% RH.
Not quite as much... Refrigerated air has a compressor and a fan that run in
cycles. Swamp coolers have a fan and a very small pump that run continuously.
Swamp coolers will always be cheaper to run, but given the limited water supply,
annual maintenance, sensitivity to humidity and relatively small temperature
drop, refrigerated air is definitely more comfortable and convenient.
You can buy a very cheap little fitting that goes in the water pump line
that permits a little hose to be attached and feed that out through the
tray drain. It slowly drains the tray as long as the pump is running.
That and water softener - a white block or a mesh bag with a white
chemical in it - in the tray helps me get by. A minimum of scraping to
prep the cooler this spring. I have very hard well water.
"Things would be a lot nicer if antique people were valued
as highly as antique furniture!" Anon
This is the best answer..
A small bleed valve that takes say 10% of the circulating water and dumps it out on the lawn.
This keeps the level of minerals from building up to no more than 10x the incomming water.
It has the same effect as the auto dump but is less expensive and more reliable and does in effect the same thing.
There is no "best" answer, only tradeoffs. Bleed valves use a lot of water - far
more than than dump pumps. If water supply isn't a concern, then a bleed valve
might be the right choice.
That said, unless you are having problems getting a swamp cooler to run a
complete season, mineral buildup on the pads isn't really a problem that
requires either solution. Mineral buildup in the pan can be dealt with during
routine end of season maintenance with a mild acid solution.
if the dump pump dumps say 20 gallons a day or you use a bleed valve and se
t it to bleed 20 gallons a day then the water usage and cleaning effect are
about the same. Not exactly the same i grant you but close enough that i
t isn't worth the cost and complexity of the dump pump.
And if the bleed water goes to water the grass or garden, then it isn't rea
Yes you have to adjust the bleed valve carefully so the percentage of water
being bled is low.
I had a long tube that led down to the garden at ground level and a valve o
n the end that i could adjust the flow without going on the roof.
After thinking $40, plus install, plus upkeep of hiccups, I think I'll
just put a tee on the main drain line, and run it an hour or so with the
drain totally open to drain all the liquid in the tub, plus flush it a
bit. We got BAD water here. All you can do is all you can do, and
that's all I can do. I estimate five years lifespan on the unit if I am
lucky. We have ag water and potable water. I think I should hook this
up to potable water, or I am going to have to add bleach or something.
I get snail shells in my control valves. It would be a booger to try to
find a clogged line in that bag of snakes.
Same here, but that's usually because the only end of season maintenance is to
insert the damper plate and maybe throw a canvas cover over the unit. The
following spring they might put in new pads every other year.
If you do the correct maintenance every fall shutdown and replace the pads every
spring, you don't get that kind of buildup. People want maintenace free swamp
coolers and there ain't no such thing.
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