"got 2 go" wrote in message
news:f0V4f.11445$MN6.903@fed1read04...
Hello Group,

I have been trying to get an explanation from the homebuilder on this, but
no explanation makes sense.

New house. Central A/C.

In the master bedroom, when the AC (or just the fan) is on, cool air comes
out of the medicine cabinet in the bathroom (through the slots that hold
the
shelves inside of the medicine cabinet).
The flow of air increases when the door of the master bedroom is closed.
But still present when it is open.

There is 1 return in the bedroom, and one outside the bedroom. They are
both
the same size filter.

Is there any time where this would be considered normal or part of the
design ?

Basically, it is up to me to prove to the builder if there is anything
wrong
with the install or not.
They sent a tech from the A/C sub they use and while he could not explain
it, he said it was probably all right.

Can anybody share their comments on this ?

Thanks in advance....




Your comments imply that you suspect the pressure in the bedroom is higher
than the bathroom and that there is an air leak in the wall which causes air
to flow through the medicine cabnet in an effirt to make up the pressure
difference.

If you are on the right track, the closed bathroom door should have air
flowing under it in the same direction as the ned cabnet. It seems like an
open door between the rooms would cancel this flow but you say it only
decreases so the pressure difference within the wall must be from an
additional room.

Look at the airspace behind the med cabnet, does it connect with any other
cavity open to another room or crawlspace. In some houses I have lived, at
least some of the return air is routed through open wall cavities rather
than closed ducts.

A cooled cabnet may indeed be good for medicine but if fed directly from the
A/C will be heated in the winter. Heating and cooling will also have
contrasting effects on the steam that condenceses on that mirror as well.

Personally, I would just pull the cabnet out, put some duct tape over the
openings and reinstall. As long as the house is comfortably heated/cooled,
what else do you want.

Also take a look at the vent in that bathroom, is air being sucked outside
through it when it is off. Cover the vent and see if this makes a
difference.