the system wasn't sealed properly to start with
the sealer is a bandaid for another problem.
the insulation shouldn't disintergrate.
I usually replace supply plenum and mastic seal all joints.
paint on mastic is cheap..its the labor that costs.
but it also gives you a chance to space ducts so that they don't touch
and don't tap off end cap or too close to ahu
and while at it....mastic everything...
.
duct take offs , where plenum connects
to equipment, supply boxes etc.
can you give us more information?
how did you find the problem?
what kind of ductwork? flex or hard pipe?
where are you located?
in hot humid climates ducts shouldn't touch each other
@ plenum ( space them apart) and shouldn't lie or be
buried in insulation because of condensation issues.
it changes for other climates.
and if it is flex, it should be straight runs with no bends
which reduce air flow.
aeroseal is one product, but I don't have much faith in it.
if gaps are over 1/4" wide...it doesn't seal these areas.
as it stays sticky the leaks it doesn't seal still allows
particles to enter and build up through out system.
this is just my experience with this product.
there have been a couple of threads about aeroseal,
just don't know if they were here or pro side.
you may have to educate the installer if you replace the
plenum.
and compare prices of interior sealant vs replacement of plenum.
best of luck.
Last edited by energy_rater_La; 12-04-2011 at 11:35 AM.
Reason: mistake
The cure of the part should not be attempted without the cure of the whole. ~Plato