Mitsubishi Electric PUZ-WZ50VAA Service Manual page 21

2-7. Water piping work
[1] Water piping connection (Fig. 2-8)
• Connect the water pipes to the outlet and inlet pipes.
(Parallel male screw for 1-inch water pipe (ISO 228/1-G1B))
• Inlet and outlet pipes position is shown on the Fig. 2-8.
• Install the hydraulic filter at the water intake.
• Maximum allowable torque at the water piping connection is 50 N•m.
• Use 2 spanners to tighten piping connections.
• Check if water leaks after installation.
• Inlet water gauge pressure must be between 0-0.3 MPa.
Note:
• The water velocity in pipes should be kept within certain limits of
material to avoid erosion, corrosion and excessive noise genera-
tion.
Be aware, and take care of, that local velocities in small pipes,
bends and similar obstructions can exceed the values above.
e.g.) Copper : 1.5 m/s
• When connecting metal pipes made of different materials, be sure
to insulate the joint to prevent electrolytic etching.
• Set up a field system so that the inlet water temperature and
water flow rate can be within the allowable range specified in our
technical data, etc.
If the unit is used out of the allowable range, the parts of unit
might be damaged.
• All automatic air vents installed in indoor water circuits MUST be
closed after the air is removed from the water circuit during com-
missioning.
×1
OCH816
[2] Water quality condition
• The water in a system should be clean and with a pH value of 6.5-8.0.
• The followings are the maximum values;
Calcium : 100 mg/L
Chlorine : 100 mg/L
Iron/manganese : 0.5 mg/L
[Fig. 2-8]
A: Water inlet
B: Water outlet
[3] Minimum water quantity
Refer to the indoor unit Installation Manual
Note: Make sure to perform the frozen prevention measure for
×2
As the outlet water temperature can reach 75°C at maximum,
do not touch the water piping directly with a bare hand.
In addition to annual servicing it is necessary to replace or inspect
some parts after a certain period of system operation.
Please see tables below for detailed instructions.
Replacement and inspection of parts should always be done by a
competent person with relevant training and qualifications.
Note:
Parts which require regular inspection
Parts
Pressure relief valve (3 bar) 1 year
Parts which require regular replacement
Parts
Pressure relief valve (PRV)
Air Separator
21
A
water pipe system. (Water piping insulation, back-up
pump system, using of a certain% ethylene glycol instead
of normal water)
Insulate the water piping properly. The performance can
be poor if the insulation is insufficient.
WARNING:
Check every
(turning the knob
manually)
Check every
6 years
B
Fig. 2-8
Possible failures
PRV would be fixed and
expansion vessel would
burst
Possible failures
Water leakage