Hitachi RAS-10HRNM, Service Manual, Page: 58 / 482

3.1 General notes
C A U T I O N
Do not install the drain-pipe in an up-slope position. Installing it like this, the drain water cannot be evacuated and
will flow back to the unit, causing a possible leakage when the operation is stopped. Always install the unit higher
than the exit of the pipe. Making this so, the water will flow easily to the outside.
INCORRECT
1. Rising part.
2. Up slope.
• Do not connect the drain pipe with the sanitary piping, the sewage piping or any other drainage piping.
• When the common drain piping is connected with other indoor units, the connected position of each indoor
unit must be higher than the position of the common drain piping. The pipe section of the common drain pipe
must be wide enough according to the unit size and the unit number.
CORRECT
1. Common drain piping.
2. Pitch of 4% (1/25) to 1% (1/100).
3. Drain piping connection.
• The drain pipe will require insulation if it is installed in a location where the ambient humidity may condensate
on the drain pipe outer surface. This condensation could drop and cause damage. The insulation for the drain
pipe must be selected in order to ensure that the vapour is sealed and in order to prevent the condensation
forming.
• The drain trap should be installed next to the indoor unit, designed according to good practice and must be
checked with charged water in order to test the correct flow. Do not tie or clamp the drain pipe and the refrigerant
pipe together.
N O T E
• The installation of a drain tap is mandatory for the RPI/10.
• Install the drainage in accordance with national and local codes.
After installing the drain piping and the electrical wiring, make sure that the water flows smoothly as the following procedure
explains:
1
2
1
2
3
3 Piping work and
refrigerant charge
50
SMGB0060 rev. 1- 12/2010