FORM 100.10-NOM2
23
YORK INTERNATIONAL
Example:
Negative Static Pressure
= 5.5"
Minimum of 1/2"
= 0.5"
“H” Dimension
= 6.0"
For blow-thru units, the same principles apply, but the
leaving pipe must be as shown in Figure 24 for proper
trap design for blow-thru unit.
Determine design negative static pressure. This pres-
sure is not the same as fan total pressure which in-
cludes pressure losses downstream as well as upstream
from the indoor-air fan. Always assume the worst con-
ditions are possible (such as having return-air filters
clogged with dirt) and add 1 inch as a safety factor.
Two drains on same side of unit must be trapped indi-
vidually before drain lines can be combined and routed
to a suitable drain. (See Figure 25)
If a drain connection is not used, then
it must be capped. This only applies
to the continuous drain pan configu-
ration with a drain connection on
each side.
Main coil drain pans and all auxil-
iary floor drain pans in the unit must
be properly trapped and charged with
water before the units are started.
BELTS AND SHEAVES
Improper sheave alignment and belt tension are poten-
tial causes of excessive noise and vibration, as well as
shortened belt and bearing life. (See Figure 26)
AIR FILTERS
All filters are shipped loose within the units. They will
be noted on the non-mounted parts packing list. Filters
must be field installed. It is mandatory that filters be in
place in the filter frames of each unit before putting the
unit into operation to protect the coils and keep them
clean.
Due to the wide variety of filters it is not possible to
cover all of them in this manual. However, when these
filters are supplied, installation instructions are shipped
with each type.
FIG. 24 –
DRAIN TRAP SHOWING PIPING FOR
BLOW-THROUGH UNIT (Positive Pressure
In Unit)
FIG. 25 –
COMBINING DRAIN LINES
FIG. 26 –
SHEAVE ALIGNMENT
LD06344
LD06345
LD06346
2
