Mitsubishi Electric PWFY-P-NMU-E-AU Engineering Manual page 35

11. SYSTEM DESIGN
11-3-4. Water Piping Installation
Water Circuit Sample
Solid arrows in the figure indicate
the direction of water flow.
PWFY
Water-side
heat exchanger
6)
12)
Consider the following when designing and installing a water piping system. (Items (1)-(12) in the figure are explained below.)
1) Union joints/flange joints etc.
Install a flange etc. to allow for easy replacement of connected equipment.
2) Thermometer
For checking unit performance and operation monitoring
3) Water pressure gauge
For operation status monitoring
4) Valve
Install a valve for easy replacement and cleaning of the refrigerant flow control device.
Install a refrigerant flow control valve on the fan coil outlet side.
5) Flexible joint
Recommended to prevent the noise and vibration from the pump from being transmitted.
6) Drain pipe
Install the drain pipe with an inclination of between 1/100 and 1/200 to provide a downward flow of drain water.
For cold climate installation, take an appropriate measure (e.g., drain heater) to prevent the drain water from freezing.
7) Pump
Use a pump that is large enough to compensate for the total water pressure loss and to supply sufficient water to the unit.
8) Air vent valve
Provide air vent valves on the pipes.
9) Expansion tank
Install an expansion tank to accommodate expanded water and to supply water.
10) Cold/Hot water pipe
Use pipes that allow for easy air purging, and provide sufficient insulation.
11) Drain valve
Install drain valves so that water can be drained for servicing.
12) Strainer
Install a strainer near the PWFY unit to keep foreign materials from entering the water-side heat exchanger.
9)
1)
City water
1)
Field supply
Uphill gradient ≥ 1/200
2) 8) 3)
1) 4)
T P
T P
1) 2) 11) 4) 3) 5) 4)
Sample of water circuit for ATW
PWFY-P-NMU-E-BU/PWFY-P-NMU-E-AU (Sept. 2010)
Roof
Overflowed water
To drain outlet
5)
P
5)
7) 4) 3) 11)
8)
Tank Outlet
Inlet
PWFY-35