Bosch LM Series, Installation, Operation And Maintenance Manual

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Condensate Drain | 7 LM Series Heat Pump
8 733 905 315 (2013/9) Revised 09-13
If the unit is located in a crawl space, the bottom
of the unit must be at least 4” above grade to
prevent flooding of the electrical parts during
heavy rains.
CONDENSATE DRAIN
Figure # 5
A drain line must be connected to the heat pump
and pitched away from the unit a minimum of 1/8”
per foot to allow the condensate to flow away from
the unit.
This connection must be in conformance with local
plumbing codes. A trap must be installed in the
condensate line to insure free condensate flow.
A vertical air vent is sometimes required to avoid
air pockets. The length of the trap depends on the
amount of positive or negative pressure on the
drain pan. A second trap must not be included.
DUCT SYSTEM
A supply air outlet collar and return air duct flange
are provided on all units to facilitate duct
connections.
Fold the duct flange outwards along the perforated
line. Refer to unit Dimensional Drawings for
physical dimensions of the collar and flange.
(Pg#55 through Pg#58)
A flexible connector is recommended for supply
and return air duct connections on metal duct
systems. All metal ducting should be insulated
with a minimum of one inch duct insulation to
avoid heat loss or gain and prevent condensate
forming during the cooling operation. Application
of the unit to uninsulated duct work is not
recommended as the unit’s performance will be
adversely affected.
The factory provided air filter must be removed
when using a filter back return air grill. The factory
filter should be left in place on a free return
system.
If the unit will be installed in a new installation
which includes new duct work, the installation
should be designed using current ASHRAE
procedures for duct sizing. If the unit is to be
connected to existing duct work, a check should
be made to assure that the duct system has the
capacity to handle the air required for the unit
application. If the duct system is too small, larger
duct work should be installed. Check for existing
leaks and repair.
The duct system and all diffusers should be sized
to handle the designed air flow quietly. To
maximize sound attenuation of the unit blower, the
supply and return air plenums should be insulated.
There should be no direct straight air path thru the
return air grille into the heat pump. The return air
inlet to the heat pump must have at least one 90
degree turn away from the space return air grille. If
air noise or excessive air flow are a problem, the
blower speed can be changed to a lower speed to
reduce air flow.
Horizontal (HZ) units must be installed
pitched toward the Condensate Drain
Connection 1/8” per foot.
HZ Heat Pump Drain Pan is not internally
sloped.
Supply air duct and return air duct flanges are
shipped unfolded with unit.
Do not connect discharge ducts directly to
the blower outlet.