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Our Process
The objective of source removal duct cleaning is the removal
of all dirt, debris and other contaminants from the
ductwork. This is recognized as the only acceptable form of
cleaning and decontaminating of air duct systems. Absolute
Environmental utilizes several different types of source
removal methods because not all systems are structurally the
same.
A conventional HVAC duct system consists of a supply system
of ducts to carry heated or cooled air from the furnace/air
conditioner (air handler) to various parts of the home or
building, and a return duct system to bring air back to be
heated or cooled again. The supply network consists of a
main duct that carries air to smaller branches for delivery
to the desired locations. The return network works in
reverse.
When to clean ducts
In houses that produce voluminous amounts of dust and mold,
ducts might need cleaning every few years. But in most homes
with reasonably modern furnaces and air conditioners, where
filters are replaced regularly, a professional cleaning is
rarely, if ever, required.
If no one in the household suffers from allergies or
unexplained symptoms or illnesses, and if a check under the
registers does not reveal large deposits of dust or mold,
cleaning is probably not necessary, according to the EPA.
You should consider having air ducts cleaned if there is a
noticeable buildup of dirt and dust despite regular filter
changes, and if there is substantial and visible mold growth
inside the ducts even though the appliances are well
maintained.
The cleaning decision also can be affected by the type of
ducts you have: traditional sheet metal, nonmetal ducts made
of fiberboard, or any type of duct (often flexible ductwork)
that has some type of internal liner.
Though there are disagreements, the EPA says current
research indicates that all types of ducts support microbial
growth to approximately the same degree. But there are some
distinctions. One is that moisture can be trapped in some
insulated duct systems, which have to be kept reasonably dry
to retard mold growth. This is not much of a problem in bare
metal ducts that have no liner or porous material to trap
moisture.
It's also easier to treat mold contamination on bare sheet
metal than on other types of ducts. Contractors can use an
EPA-registered biocide (often called a sanitizer) on bare
metal.
But once a fiberglass duct liner is contaminated with mold,
cleaning is not sufficient to prevent regrowth, according to
the EPA. One obvious reason: No products are currently
EPA-registered as biocides for use on fiberglass duct board
or fiberglass-lined ducts. Both the EPA and the
Washington-based National Air Duct Cleaners Association (NADCA)
recommend replacing wet or moldy fiberglass duct material.
The procedure
Cut an access hole in the main ductwork, and attach a
negative air machine to the hole.
Remove the vent covers in the home, cleaning each one
thoroughly. After cleaning is complete, each vent cover is
plugged with foam to ensure that debris does not flow
through a vent opening during cleaning and creates a
powerful negative air pressure inside the ductwork after the
vacuum is turned on.
Turn on the vacuum and go to the vent furthest away from the
main system and pull out the plug. All force will go to that
vent, and then an agitator is introduced into the opening to
dislodge all debris from the walls of the ductwork. Method
of agitation varies depending on the size and type of
ductwork and includes spin brushes, and air operated whips.
(Note: the furnace will be zoned off so no debris will be
pulled through the system).
.This agitator supplies approximately 200 pounds per square
inch of compressed air, and is used to push all the debris
to the vacuum while the vacuum is pulling. This is
frequently called the "positive- negative" method and is the
way NADCA mandates that duct cleaning be performed.
The return ductwork is cleaned in mostly the same way.
However, often times the return ductwork is wide enough to
allow us to use hand brushes and vacuums in addition to
agitation.
Replace all vent covers, and close any access cuts. Access
cuts are closed with pre-fabricated sheet metal doors, which
are attached with self-tapping screws then sealed with foil
tape. This leaves a convenient access door for future
ductwork maintenance, and will not affect air-flow.
Remove the panels on the air handler, and brush and vacuum
the encasement, the fan, the blower and all other accessible
components, also cleaning the coils. |
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