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MOUNTING HORIZONTAL UNITS
While horizontal units may be installed on any level surface strong
enough to hold their weight, they are typically suspended above a
ceiling by threaded rods. The rods are usually attached to the unit
corners. The rods must be securely anchored to the ceiling. All
50HQP units include an integral angle iron frame with mounting
holes present. (See unit horizontal detail drawing.) Horizontal
units installed above the ceiling must conform to all local codes.
An auxiliary drain pan if required by code, should be at least four
inches larger than the bottom of the heat pump. Plumbing connect-
ed to the heat pump must not come in direct contact with joists,
trusses, walls, etc.
Some applications require an attic floor installation of the horizon-
tal unit. In this case the unit should be set in a full size secondary
drain pan on top of a vibration absorbing mesh. The secondary
drain pan prevents possible condensate overflow or water leakage
damage to the ceiling. The secondary drain pan is usually placed
on a plywood base isolated from the ceiling joists by additional
layers of vibration absorbing mesh. In both cases, a 3/4-in. drain
connected to this secondary pan should be run to an eave at a loca-
tion that will be noticeable. If the unit is located in a crawl space,
the bottom of the unit must be at least 4 in. above grade to prevent
flooding of the electrical parts due to heavy rains.
Step 5 — Check 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 out-
wards along the perforated line. Refer to Fig. 2-6 for physical di-
mensions of the collar and flange.
NOTE: All dual fan units (50HQP 120 and 180-242, 50VQP 210-
360) must use a "pair of pants" duct configuration as shown in
Fig. 14. Failure to follow these guidelines can result in fan system
failure.
A
a50-8357.eps
Fig. 14 — Typical Fan Discharge Connections for
Multiple Fan Units
NOTE: A = 1-1/2 to 2-1/2B
B
Refer to ASHRAE (American Society of Heating, Refrigerating
and Air-Conditioning Engineers) standards for the recommended
duct connection to units with 2 fans. An adequate straight length
of ducting from the unit should be allowed before elbows are in-
stalled. Elbows should turn in the direction of fan rotation, if pos-
sible. Abrupt turns will generate air turbulence and excessive
noise. Turning vanes should be used in all short radius bends. En-
sure that ducting does not obstruct access to the unit for routine
servicing.
A flexible connector is recommended for supply and return air
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 cool-
ing operation. Application of the unit to uninsulated duct work is
not recommended as the unit's performance will be adversely af-
fected. Do not connect discharge ducts directly to the blower out-
let. The factory provided air filter must be removed when using a
filter back return air grille.The factory filter should be left in place
on a free return system. If the unit will be installed in a new
installation with new ductwork, the installation should be designed
using current ASHRAE (American Society of Heating, Refriger-
ating, and Air-Conditioning Engineers) procedures for duct sizing.
If the unit will be connected to an existing duct system, 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 ductwork must be installed. Be certain to check
for existing leaks and repair.
The duct system and all diffusers should be sized to handle the de-
signed airflow 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 through 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 airflow are a problem, the blow-
er speed can be changed to a lower speed to reduce airflow.
Step 6 — Install Condensate Drain
Verify condensate switch is installed in the lowest part of the
drain pan, based on unit pitch. Condensate switch may need to
be relocated from factory position.
A drain line must be connected to the heat pump and pitched away
from the unit a minimum of 1/8-in. per foot to allow the conden-
sate to flow away from the unit. 50VQP vertical units include one
condensate drain. 50HQP horizontal units include two condensate
drain connections to allow for field pitching based on installation
requirements. Only one condensate drain connection should be
used. Cap and seal the unused drain connection.
Units with waterside economizer include an additional condensate
pan and drain as part of the economizer assembly. This drain must
also be piped to a condensate line following the guidance above.
NOTE: the waterside economizer condensate pan is not protected
by a condensate overflow switch from the factory.
This connection must be in conformance with local plumbing
codes. A trap must be installed in the condensate line to ensure
free condensate flow. (Units are not internally trapped.) A vertical
air vent is sometimes required to avoid air pockets. (See Fig. 15.)
The length of the trap depends on the amount of positive or nega-
tive pressure on the drain pan.
15
CAUTION
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