Unit Piping - Daikin RDT-135c Installation And Maintenance Manual

Mechanical Installation: Unit Piping

Unit Piping

Condensate Drain Connection
The unit is provided with a 1.5" male NPT condensate drain
connection. Refer to certified drawings for the exact location.
For proper drainage, level the unit and drain pan side to side
and install a P-trap
RPS units may have positive or negative pressure sections.
Use traps in both cases with extra care given to negative
pressure sections. In Figure 51, dimension "A" should be a
minimum of 8" (203 mm). As a conservative measure to
prevent the cabinet static pressure from blowing or drawing
the water out of the trap and causing air leakage, dimension A
should be two times the maximum static pressure encountered
in the coil section in inches w.c.
Draining condensate directly onto the roof may be acceptable;
refer to local codes. Provide a small drip pad of stone, mortar,
wood, or metal to protect the roof against possible damage.
If condensate is piped into the building drainage system, pitch the
drain line away from the unit a minimum of 1/8" per foot. The
drain line must penetrate the roof external to the unit. Refer to
local codes for additional requirements. Sealed drain lines require
venting to provide proper condensate flow.
Where the cooling coils have intermediate condensate pans on
the face of the evaporator coil, copper tubes near both ends of
the coil provide drainage to the main drain pan. Check that the
copper tubes are in place and open before the unit is put into
operation.
On units with staggered cooling coils, the upper drain pan
drains into the lower coil drain pan through a copper tube near
the center of the drain pan. Check that this tube is open before
putting the unit into operation and as a part of routine
maintenance.
Because drain pans in any air conditioning unit have some
moisture in them, algae, etc. will grow. Periodically clean to
prevent this buildup from plugging the drain and causing the
drain pan to overflow. Clean drain pans to prevent the spread
of disease. Cleaning should be performed by qualified
.
personnel
Drain pans must be cleaned periodically. Material in
uncleaned drain pans can cause disease.
Cleaning should be performed by qualified personnel.
44
WARNING
Figure 51. Condensate drain connection
Gas Piping
See the "Installation" section of the gas-fired furnace
installation manual, Bulletin No. IM 684 or 685.
Hot Water Coil Piping
Hot water coils are provided without valves for field piping or
piped with three-way valves and actuator motors.
All coils have vents and drains factory installed.
Note:
Hot water coils are not normally recommended for use with
entering air temperatures below 40°F (4°C). No control system
can guarantee a 100% safeguard against coil freeze-up. Glycol
solutions or brines are the only freeze-safe media for operation
of water coils at low entering air temperature conditions.
When no factory piping or valve is included, the coil
connections are 1 5/8" ODM copper.
With the factory piping and valve package, field piping
Note:
connections are the same NPT size as the valve with
female threading (see Figure 53 on page 45).
Refer to the certified drawings for the recommended piping
entrance locations. Seal all piping penetrations to prevent air
and water leakage.
Factory-installed water valves and piping are bronze,
Note:
brass, and copper. Dissimilar metals within the
plumbing system can cause galvanic corrosion. To avoid
corrosion, provide proper di-electric fittings as well as
appropriate water treatment.
V i e A
IM 738-2