"Rick" wrote in message
...
Thanks. The grille was in plastic with a 20x20 sticker on it, which means
nothing as it had a filter already crammed in it (19 1/8 square, and bent).
It's a pretty good company, so I don't know what's going on. The city is
coming
out to inspect the air handler this week, so I'll let drop that I may chat
about
this issue with her.
The plenum box measures 20x20 exactly, so it may be a close fit but the grille
is square.
They will have some fun as I'm asking my father (a mech PE) to run some
numbers
Tuesday to see if the grille is sized correctly for the tonnage. I need to
get
flow numbers from 3M, but I bet all the plenums are under size. The previous
owner of the house was a do-it-yourselfer, and now I'm cleaning up after him
:-)


This is turtle.

We HVAC peoples have air flow charts we have in telling what size we need for
certian tonage units and I'm looking at one. Tell me what it is and I can look
it up.

If a 20'' x 20'' return grill will not let a 20'' X 20'' filter go in it. You
have a big problem there for that is not suppose to happen at all.

TURTLE