Piping Installation - LG AR-DR12-05A Installation And Operation Manual

PIPING INSTALLATION

Optional Gas Piping
Units with indirect gas-fired furnaces require field- supplied and
installed gas supply piping. The unit gas connection is 3/4-inch NPT.
The maximum allowable gas pressure is 14 in. wg.
Gas Connections
If this unit is equipped with an indirect gas-fired furnace, connection
to an appropriate gas supply line will be required. For complete
information on installation procedures for the optional gas furnace,
refer the PVF/PVG Indirect Gas-Fired Heat Module Installation,
Operation, and Maintenance Manual.
Optional Coil Piping
Factory-installed cooling and heating components are mounted in
the coil section of the unit. The coil section is downstream of the
energy wheel on the supply air side of the unit. Note the coil connec-
tion locations on the picture. Coil connections are located external to
the unit as shown.
1. Piping should be in accordance with accepted industry standards. Pipework should be supported independently of the coils. When install-
ing couplings, do not apply undue stress to the connection extending through the unit. Use a backup pipe wrench to avoid breaking the
weld between coil connection and header.
2. Connect the water supply to the bottom connection on the air leaving side and the water return to the top connection on the air entering
side. Connecting the supply and/or return in any other manner will result in very poor performance. Be sure to replace factory-installed
grommets around coil connections if removed for piping. Failure to replace grommets will result in water leakage into the unit and altered
performance.
3. Water coils are not normally recommended for use with entering air temperatures below 40°F. No control system can be depended on to
be 100% safe against freeze-up with water coils. Glycol solutions or brines are the only safe media for operation of water coils with low
entering air conditions. If glycol or brine solutions are not used, coils must be drained when freezing conditions are expected. If required,
vent and drain connections must be field-piped, external to the unit.
4. Pipe sizes for the system must be selected on the basis of the head (pressure) available from the circulation pump. The velocity should
not exceed 6 feet per second and the friction loss should be approximately 3 feet of water column per 100 feet of pipe.
5. For chilled water coils, the condensate drain pipe should be sized adequately to ensure the condensate drains properly. Refer to Drain
Trap section.
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Due to our policy of continuous product innovation, some specifications may change without notification.
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Manual
Shut O
Valve
from
Gas
Supply
Bleeder Valve or
1/8 in Plugged Tap
Gas to
Controls
Ground
Joint
Union
8 in Trap