Tyler Refrigeration N7DNL, Installation & Service Manual

Installation & Service Manual

N7DNL, NHD

June, 2007

Page 19

Figure 2 shows
what happens to
the air flow when
the shelves are
removed.  The air
drifts back to the
rear duct and
swirls about.  This
breaks the protec-
tive barrier, caus-
ing the case air to
mix with ambient
air to a great
extent. 

Peg Bar Information

The hang up blister pack has become a standard means of marketing sliced luncheon meats and
other delicacies.  It appears that all that is needed to adapt multi-shelf cases for these packages
is to add peg bars and pegs.  However, it isn’t quite that simple, because the removal of shelves
changes more than the appearance of the case.

Figure 1 shows
the air flow in 
a Multi-Deck dis-
play merchandiser
with shelves.  Air
flow from the top
and back forms a
protective barrier
to ambient air.

Figure 4 shows the
proper air flow for
cases with peg
bars.  The addition
of a baffle above
each row of peg
bars, except the 
top row and a bot-
tom shelf, maintains
proper air flows 
and temperatures 
in the case.  Non-
load bearing air 
baffles should run
the same width as
the peg bars. 

Figure 3 depicts what happens to the air flow 
in a case full of peg bars.  The air falls through
openings between packages and fails to main-

tain a protective
barrier.  When the
bars are fully
stocked, the effect
is minimized, but
product tempera-
tures will not be 
as good as they
could be.  Sweating
may be noticed on
the top duct panel
above the bars.
The coil will also
frost faster, requiring
more frequent
defrosts.

CAUTION

Always use one row of shelves below the lowest row of peg bars.  Use air baffles above
each row of peg bars, except the top row.  The air baffle should be solid in design and 
positioned 1” in front of the rear duct and 5.5” back from the rear edge of the card 
moulding.  This provides and maintains the protective air flow in the case and proper 
product cooling and storage.