Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 844

FDC-HKX
(d) Drain Piping
1) Drain piping should always be in downhili grade (1/50 ~ 1/100) and avoid riding across and elevation or making traps.
• Good piping
Suspension
1.5 m ~ 2 m
bolts
Heat A downhill grade
insulation of 1/100 or more
2) When connecting the drain pipe to unit, pay sufficient attention not to applay excess force to the piping on the unit side. Also,
fix the piping at a point as close as possible to the unit.
3) For drain pipe, use hard PVC general purpose pipe VP-25(I.D.1")
which can be purchased locally. When connecting, insert a PVC
pipe end securely into the drain socket before tightening securely
using the attached drain hose and clamp. Adhesive must not be
used connection of the drain socket and drain hose (accessory).
4) When consturcting drain piping for several units, position the com-
mon pipe about 100 mm below the drain outlet of each unit as
shown in the sketch. Use VP-30(11/4") or thicker pipe for this
purpes.
5) Be sure to provide heat insulation to hard PVC pipes of indoor
placement.
6) Do not ever provide an air vent.
7) The height of the drain head can be elevated up to a point 700 mm ablve the
ceiling and, when an obstacle exisits in the ceiling space, elevate the piping to
avoid the obstacle using an elbow or corresponding gadget. When doing this, if
the stretch for the needed height is too high, the back-flow quantity of drain at the
event of interruption of the operation gets too much and it may cause overflow at
the drain pan. Therefore, make the height of the drain pipe within the distance
given in the sketeh below.
8) Avoid positioning the drain piping outlet at a place where generation of odor may
be stimulated. Do not lead the drain piping direct into a sewer from where sulfur
gas may generate.
9) The purpose of drain hose is to absorb minute discrepancy of the unit or the drain
piping occurred when they are installed. Therefore, when it is bent intentionally
or used under expanded condition, it may be damaged and result in water leak-
age.
Drainage Test
1 Conduct a drainage test after completion of the electrical work.
2 During the trial, make sure that drain flows properly through the piping and that no water leaks from connections.
3 In case of a new building, conduct the test before it is furnished with the ceiling.
4 Be sure to conduct this test even when the unit is installed in the heating season.
Procedures
1 Supply about 1000 cc of water to the unit through the air outlet by using a feed water pump.
If the electrical work has not been completed, connect a convex joint in the drain
pipe connection to provide a water inlet.
Then, check if water leaks from the piping system and that drain flows through
the drain pipe normally.
2 Check at the exhaust port if drain is flowing.
(Note) Conduct this test paying attention to rotating sound of the drain motor.
3 Remove the drain plug located on the bottom of the drain pan when the water has to be evacuated from the unit.
4 After the test, fit the drain plug to the original place and turn off the power source.
842
• Improper piping
Air vent
Main unit
Drain socket
Pour water into a convex joint
Avoid riding across an elevation
Keep free from traps
Do not pipe under water
Stage
difference
Drain hose
Drain socket
part
VP25 joint
Pipe cover (large) (field purchased)
[for insuation]
(accessory)
Drain hose
VP25
(accessory)
(field purchased)
Clamp
Adhesion
(accessory) Pipe cover
[for insuation]
Pipe cover (small)
(field purchased)
[for insuation]
(accessory)
Secure the elevation as high as possible
(approx. 100 mm)
A downhill grade of
VP30
1/100 or more
295 ~ 325 mm 100 mm or less
Drain hose
VP25 joint
(field purchased)
Put the tip of the feed water pump
in the drain pan of the unit body