Instruction Manual

HOT WATER COIL PIPING
CDX-HW CDXX-HW: Installation, Operation, and Maintenance Instructions
7
HOT WATER COIL PIPING
Refer to Flow Control Module installation instructions for proper pump
installation, if used.
CAUTION: When connecting piping to fan coil units, do not bend or reposition the coil header
tubing for alignment purposes. This could cause a tubing fracture
resulting in a
water leak when pressure is applied to the system.
WARNING: An expansion tank may be required if a back-flow preventer is installed in the
system.
CDX-HW / CDXX-HW
All piping between the water heater and fan coil unit should be 3/4” nominal
(7/8” OD) copper pipe to prevent excessive head pressure loss. If copper or
other piping material is used the installer must calculate its pressure drop and
size pipe and overall length accordingly to match the performance of the
circulator. Maximum GPM through the coil is 4.0 GPM.
It is also recommended that all piping be adequately insulated to prevent
freezing when piping is run in an unconditioned space.
NOTE: The CDX-HW fan coil unit comes with a hot water coil freeze protector. This
device may not sufficiently protect the water lines if the fan coil is located in
ambient air locations (attics, crawl spaces, etc.) or within structures that may
be unoccupied during freezing conditions. Consult the factory for additional
information.
Solder Connections
- All copper joints in the water lines must be made with low
temperature - non lead solder.
"T" Connections
(at the water heater)- Water lines to and from the fan coil unit
must be taken from the horizontal connection of the "T" fittings in the vertical
hot and cold water supply lines at the water heater. This ensures that any air in
the system will be purged each time water is used in the dwelling.
Isolation Valves -
Two valves are recommended to be installed within the
circulating loop to permit servicing of the system if required and to assist in
purging the system.
C
OOLING
C
OIL
P
IPING
The CDX-HW fan coil units are supplied with a direct expansion refrigerant coil.
The refrigerant metering device is either a fixed orifice piston or Bi-directional
TXV and is installed at the factory. This permits the unit to be matched with
either a standard condensing unit or heat pump. The suction and liquid
refrigerant lines must be sized in accordance with the outdoor unit
manufacturer’s recommendations.
CONDENSING
PIPING
Condensate drain lines must be installed with adequate slope away from the
unit to assure positive drainage. Since the drain pan is located on the suction
side of the blower, a negative pressure exists at the drain pan and a minimum
trap of 1-1/2 inches should be provided in the drain line to assure proper
drainage. The fan coil unit may be located where the return air space is large
enough that a negative pressure is not present, however, a trapped condensate
line is recommended in case a negative condition should occur, the unit would
drain properly.