Installation manual

035-16682-000-E-0303
18 Unitary Products Group
NOTE: The steam control valve, power and control wiring to
the actuator of the valve is the responsibility of the
installing party.
PIPING CONNECTIONS
Refer to Tables 43 through 46 and Figures 47 and 48 for flow
rate and capacity.
The steam piping must enter the unit through the floor of the
heat section compartment. The access doors to the compart-
ment are gasketed so the compartment can be sealed. How-
ever, as added protection for condensate leakage into the
space, the piping access holes should be sealed with a heat
resistant mastic. The following figure illustrates the location of
the compartment and piping connections.
ECONOMIZER SETPOINT ADJUSTMENT
This control is located in the upper portion of the control cabi-
net.
For Dry Bulb Economizer see Figure 14.
For Single Enthalpy Economizer see Figure 13 and 15.
For Dual Enthalpy Economizer set changeover switch fully
clockwise (D).
See System Setpoints in the SYSTEM START-UP section for
more information.
CHECKOUT PROCEDURE
Connect 620 ohm resistor across terminals SR and +.
Connect 1.2K ohm checkout resistor (4074EJM) across ter-
minals S0 and +.
Turn enthalpy setpoint to A -- LED turns ON.
Turn enthalpy setpoint to D -- LED turns OFF.
STATIC PRESSURE CONTROL PLASTIC TUBING
On units with inlet guide vanes (IGV's) and variable fre-
quency drives on the supply blower and/or power exhaust
fans, pressure sensing tubing must be field supplied and
installed from differential pressure switches or transducers to
the locations in the building or ductwork where a constant
pressure is desired, and to the atmosphere.
The supply air discharge static pressure switch or transducer
is located in the blower compartment on the heat section par-
tition panel. Plastic tubing (1/4") must be run from the high
pressure tap of the transducer to a static pressure tap (field
supplied) in the supply duct located at a point where constant
pressure is desired. Tubing must also be run between the low
pressure tap of the transducer to atmospheric pressure.
All piping and control valves, and wiring that is
field installed must be properly insulated and con-
form to all local and national codes.
There are no provisions in the coil or control
sequence to prevent freezing of condensate. The
control valve, piping and field installed wiring con-
nections are particularly vulnerable because they
are installed in the vestibule outside of the condi-
tioned air stream. The installing party will be
responsible for properly insulating and installing
power and control wiring, to the actuator and pip-
ing.
DO NOT use steam coils as hot water coils under
any circumstances.
In steam coil systems, the steam pressure shall
not exceed 15 PSI.
Piping access holes should be sealed with a heat
resistant mastic to prevent damage to equipment.
DO NOT use tin based solder. Brazing with tin
based solder could cause equipment damage or
possible injury to tenets of the structure that is
being conditioned.