Unit installation

10 Daikin IM 980-1
Installation
1 Vent the vacuum breaker line to atmosphere or connect it
into the return main at the discharge side of the steam
trap.
2 Pitch all steam supply and return mains down a
minimum of one inch per ten feet in the direction of flow.
3 Do not drain the steam mains or takeoff through the
coils. Drain the mains ahead of the coils through a steam
trap to the return line.
4 Overhead returns require one psig of pressure at the
steam trap discharge for each two-feet elevation to
ensure continuous condensate removal.
5 Proper steam trap selection and installation is necessary
for satisfactory coil performance and service life. For
installation, use the following steps:
a Position the steam trap discharge at least 12 inches
below the condensate return connection. This
provides sufficient hydrostatic head pressure to
overcome trap losses and ensure complete condensate
removal.
b Daikin recommends using flat and thermostatic
traps because of gravity drain and continuous
discharge operation.
c Use float and thermostatic traps with atmospheric-
pressure gravity condensate return, with automatic
controls or where the possibility of low pressure
supply steam exists.
d Always install strainers as close as possible to the trap
inlet side.
Two-pipe systems with electric heat
The electric heating coil is designed to be the total source of
heat for the unit. If used for auxiliary intermediate season
heating, additional control is required. A second switch or pipe
sensor is required. Contact your Daikin representative for
more information.
To protect the electric heat elements, an automatic and manual
electric heat switch disengages the electric heat to prevent
overheating. For information on resetting the manual switch,
see Electric Heat Over-Temp Reset Button‚ page 17.
External Insulating Requirements
Insulate and vapor-seal surfaces that are colder than the
surroundin
g air dew point to prevent unplanned condensation.
Daikin recommends field-insulation in the following areas to
prevent potential condensate problems:
• Supply and return water piping connections
• Condensate drain lines and connections
• Fresh air intake duct connections
• Discharge duct connections
• Wall boxes
Electrical Connections
Installation and maintenance must be performed only by
qualified personnel who are familiar with local codes and
regulations, and are experienced with this type of equipment.
Standard Electrical Connection
Field electrical power connections are made in the electrical
junction box, which is mounted to the control box on the side
of the chassis opposite the primary coil piping connections.
See Figure 11. If the unit is equipped with an optional
disconnect switch, it is located in this junction box.
Units with an electric heat option that has the same voltage as
the unit can bring the power conductors into this same junction
box. Units with electric heat that has a different voltage should
bring the electric heat into one of the knockouts on the control
box. See Figure 11.
Low voltage wires should be brought into the conduit located
next to the field electrical power junction box. See Figure 11.
Figure 11: Electrical Power Connections
If electrical wiring or conduit comes through the floor, all
wires or conduit should be sealed at this point. It will prevent
any condensation or water leakage that may occur due to lack
of preventive maintenance.
Note: Wiring coming through the wall should be sealed to stop cold air
infiltration through the wall cavity, which could affect unit
thermostat operation. Wiring coming through the floor should be
sealed to prevent condensation or water leakage from reaching
live wires.
DANGER
Hazardous Voltage!
The installer must determine and follow all applicable codes
and regulations. This equipment presents hazards of
electricity, rotating parts, sharp edges, heat and weight. Failure
to read and follow instructions can result in property damage,
severe personal injury or death.
Low-voltage
conductors
brought in here
Electric heat
power conductors
brought in here
Unit power
conductors
brought in here