On Sat, 18 Jan 2014 20:46:59 -0500, Stormin Mormon
I am not a mechanical inspector so I am not sure of the code but it is
a horrible "design" choice.
In inspector talk "design" is the gray area between "code" and things
that are just a dumb idea.
Put all of that heat and noise under your deck? Nuts.
The fire thing is secondary. I am not sure a condenser catching on
fire under a dry pine tree, next to your house is a good thing either
and that installation is perfectly legal.
I don't know how many times I've had to explain to some idiot that you
must have free air circulation for any condensing unit. The video showed
some condensers mounted on a wall off the ground and that's the way to
do it if there is landscaping around the darn things. Me and my late
friend GB built a platform 6' off the ground for a 5 ton condenser at a
restaurant so cars could pull up to the building and park. It rarely
needs cleaning because it's above the dirt that's at ground level. ^_^
I some how guessed that TDD would see the air
circulation problem, and how the unit just
recycles the heat. This one must have been
cooking hot, and kept tripping the overload
protector. Thank you for bringing common sense
to this list.
On Sunday, January 19, 2014 7:21:59 AM UTC-5, Stormin Mormon wrote:
While I agree 100% that unit should never have been installed
where it was, I still wouldn't think it should cause a fire.
It would certainly run inefficiently, but I don't see how that
alone could generate enough heat to start a fire. I would suspect
that something had to fail and it's entirely possible it wasn't
related to the heat at all. Certainly someone dumb enough to install
it that way is also dumb enough to do something else wrong, ie
improper electrical connection, etc. It's also possible the installer
put it in before the deck was installed. Even if the sides were not
there, it's still no place for the unit to be.
Stolen without permission from decks.com:
"Building a deck over an air conditioner
Sometimes an existing air conditioning unit is installed in the location
where you want to build a new deck. Your best option is to move the unit
to another location out of the way. This might cost you a few hundred
dollars but will save you a lot of headaches in the long run. Most AC
manufacturers recommend maintaining a minimum 60" uninterrupted clearance
above the compressor to allow for hot air to exhaust from the top of the
unit. Without proper air flow your AC unit can overheat and break down.
You must also consider access for repairs of the unit. If your deck is
very high you may be able to leave it in place but keep in mind that AC
units can be very noisy and hot."
I don't know why more installers don't get the darn things off the
ground away from the dirt that can get sucked into them. I always told
customers to turn the AC/heat pump off when the grass is being cut
anywhere near the outside unit. Getting the condenser off the ground
just a little like putting the pad on concrete blocks will keep it a lot
cleaner. Of course I did a lot of commercial work where the condensing
units were on the roof but they still got dirty. Most guys
don't know to install head pressure controls on condensing units for
commercial sites that will run the AC during the winter. The easiest way
is to install a pressure switch on the high side to control the
condenser fan. Me and GB would install high and low pressure cut out
pressure switches for residential customers who had furry pets which
would cause hair to clog the condensing unit. The low pressure switch
was to save the compressor if the refrigerant leaked out. Me and GB
would do all sorts of things to help customers keep their systems
running like installing surge arresters and anti short cycle timers. ^_^
I vacuum my condenser fins as part of my fall clean-up tasks. This year
must have been overly active year for the cotton wood trees in the area.
When I removed the shroud it looked like the condenser fins were wearing a
blanket. It was about a 1/4" thick. I could peel it off in big sheets. This
is the first time it's looked that bad.
What are your thoughts on adding a "pre-filter" by wrapping the unit in
fiberglass screen material? Do you think that would restrict the air flow
too much? I'm sure the air was seriously restricted by the cotton wood
dust, so one way or the other it's going to be less efficient. At least I
could clean the screen material easily and often as opposed to pulling the
shroud multiple times over the season.
Me thoughts that few people have the attention to
detail to make a prefilter work, for condensing
unit. I sense that you are one of the few who does.
Brush and vac cleaner is better than no cleaning,
but chemicals and garden hose is better yet.
I walk by my condenser almost every time I'm in the backyard. It's close to
my back door and right next to the hose spigot. It would be tough not to
notice the build up of "lint" on the pre-filter.
One possible method would be a screen covered wooden frame, a few inches
larger than the unit, that could fit right over the unit. If designed
correctly, it could provide filtering for the sides and the few inches of
gap at the top, yet allow free airflow from the top of the unit. When it
got dusty, it could be lifted off and hosed down or vacuumed.
My only concern would be the lack of airflow _into_ the unit. I remember a
summer many years ago when I was an inquisitive teenager. My grandfather
had two matching table fans. One had the cage covered with aluminum
screening, the other did not. It was the first time I realized how much air
flow a window screen can inhibit.
A garden hose would still require removal of the shroud to achieve a good
cleaning of the fins. If I want to do it multiple times a season, that's
where the PITA exists.
Another option would be to remove the screws that hold the shroud on -
especially the ones on the bottom back of the unit where they are hard to
get to - and use a couple of ratchet straps to make the R&R easier. I
haven't looked close enough into that option to see if the shroud has
enough support to hold it's shape with straps and no screws.
Many manufacturers install a plastic screen with 1/4" square openings
and it looks like a plastic version of metal hardware cloth but it's
more about protecting the aluminum fins than filtering air. The airflow
through a typical condensing unit is so high that a filter of even
window screen would be impractical because it would clog up very
quickly. The only way I would ever use something like that is if I had a
manual reset high pressure cutout switch installed on the unit. It
sounds like you could use one on your condenser now. The newer high
efficiency units are more prone to clogging than older systems because
there is less space between the fins. I've seen old units that rarely
clogged up because of their wide fin spacing. If you use your shop-vac
and brush attachment to clean your condenser without bending any fins,
that's OK but it would be even better to use the wide spray from your
garden hose to wash it out too. Don't use the narrow stream from your
garden hose because it will bend the fins over and cut air flow. Over
the years I've had to comb out a lot of fins on condensing units when
some doofus thought it would be helpful to blast the dirt out of a
condensing unit using the narrow stream from a garden hose nozzle. The
big box stores sell an aerosol can of cleaner for your AC unit that does
a pretty good job of cleaning it up perhaps not as well as the
professional cleaning chemicals but you're not likely to damage your
unit by using it. ^_^
I am in my backyard almost every day, so I would be able to see clogged
screening much better that I can see clogged fins. If I built a frame to
slip over the condenser, then removal, cleaning and replacement would be a
How do I know of I have one on my unit? If I don't, what would it take to
What do you consider an "old unit"? I don't have the install date handy,
but if believe it was roughly 2006 but it's not one of the taller units you
see these days. I believe it was installed during the period where vendors
could install the lower efficiency units if they still had them in stock.
Does that sound familiar?
SM: If the frame was good window screen, you could rinse that with a
garden hose, as needed.
SM: Switch, on the small line coming off the compressor. Typically about
an inch round, black with a red button. Since install involves brazing
into the refrigeration line, needs a HVAC tech to install. I've not
installed one, but from what I know, would need to pump out the
refrigerant ("freon") then braze in, and put the refrigerant back. Two
hours work, maybe. TDD can comment in more detail.
SM: I've also found useful to spray from a high angle, towards the
ground. Rinse the dirt out, instead of packing it farther in. n Derby's
case, he may have some success by taking the fan off the top, and rinse
from inside out.
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