Return Plenum and transition

[wak]

Hi
I'm changing pretty much my whole system today. But the ceiling boxes. The are replacing duct work, supply plenum, AC furnace and coil.
They are NOT replacing the return plenum and transition. They are saying it looks fine. I see that the insulation looks black from dust but they insist is fine.
Should these pieces be changed or this won't affect anything?

[energy_rater_La]

I'd change it.
some ductboard has black coatings
sheetmetal insulation has black facing into plenum.
return leakage contributes to high RH in our climate.

this leakage is past the filter, so where this sucks in
air it brings air/dust etc to collect on coil.

dust is an indication of leakage. at the minimum
clean off dust and make sure that they mastic seal all
the connections.

same with supply plenum connections and each supply duct take off.
sealing supply boxes at ceiling will help reduce duct loss also.

best of luck.

[welling service]

How old is your system and how long of a run is your RA duct? Is it round or square duct? The duct insulation used years ago had a tar impregnated paper facing that turned dark over time. I agree with energy_rater that you should at least have them check the duct for air leaks. Take a look at the air entering side of the evaporator coil. If it is real dirty than you know you are bypassing the air filter somewhere which is most likely your RA duct.

[wak]

I'd change it.
some ductboard has black coatings
sheetmetal insulation has black facing into plenum.
return leakage contributes to high RH in our climate.

this leakage is past the filter, so where this sucks in
air it brings air/dust etc to collect on coil.

dust is an indication of leakage. at the minimum
clean off dust and make sure that they mastic seal all
the connections.

same with supply plenum connections and each supply duct take off.
sealing supply boxes at ceiling will help reduce duct loss also.

best of luck.

They are changing the supply plenum. they are going to clean dust and they also are saying that the whole home purifier is after the return so that stuff is not going to make it to the system. They say it doesn't look bad.

I don't know much about this stuff so I don't know what is bad or what is not.

[energy_rater_La]

if it is dirty..you have leakage. return leakage contributes
to high RH indoors.
if they don't want to do the work..they will
say it is ok.

are they using mastics to seal new supply plenum?
don't let them duct tape of foil tape the leakage
it might seal now..but later it will leak.

we've seen other systems to base
our answers upon. if the company wants
to hurry through the sealing will be minimal.
your costs to operate won't.

best of luck.

[wak]

if it is dirty..you have leakage. return leakage contributes
to high RH indoors.
if they don't want to do the work..they will
say it is ok.

are they using mastics to seal new supply plenum?
don't let them duct tape of foil tape the leakage
it might seal now..but later it will leak.

we've seen other systems to base
our answers upon. if the company wants
to hurry through the sealing will be minimal.
your costs to operate won't.

best of luck.

This is what the coil looks like.
They are going to mastic and seal all connections. Also the insulation look black because the material was black as somebody suggested. Should it be replaced anyway?

[energy_rater_La]

take a picture of it hard to see from here!

[jpsmith1cm]

welling service

Please check your e-mail.

Thanks,

AOPC