Mitsubishi Electric QAHV-N560YA-HPB Data Book page 38

4. System Design
4-2-4. Configuration method and selection criteria of flow rate adjustment device
In this system, a flow rate adjustment device is installed in the secondary side circuit to perform secondary side flow
rate adjustment control by outputting 0 to 10 V from the unit.
* 10-V power supply is not supplied.
The following shows a system configuration example of the flow rate adjustment device and notes on the system
configuration.
The following three system types are recommended as flow rate adjustment devices:
1. System using a three-way valve
2. System using a two-way valve
3. System using an inverter
1. System using a three-way valve
ON/OFF signal
0 to 10 V output
Notes on selection method and system configuration
Notes on pump selection and connection
 Calculate the total pump head according to the system at the site and then select a pump capable of outputting
the minimum flow rate of about 3 ℓ/min and maximum flow rate of about 30 ℓ/min with the necessary pump
head for the piping at the site.
 When selecting the pump, please note that output at a high flow rate will not occur if the flow rate with the
pump head of the system at the site is low, and output at a low flow rate will not occur if the flow rate is too high.
 Be sure to check that the flow rate becomes 20 to 30 ℓ/min at the maximum output during a flow rate
adjustment test run.
* If the flow rate is not within the range of 20 to 30 ℓ/min, select a different pump or adjust the maximum
frequency using an inverter, etc. so that the maximum flow rate of 20 to 30 ℓ/min is achieved.
* To select a proper pump, first select a pump that supports slightly high flow rate, and then adjust the frequency
with an inverter so that the flow rate becomes 20 to 30 ℓ/min at the maximum output.
(In that case, an inverter is necessary to be prepared separately.)
Notes on three-way valve selection and connection
 Use a valve that is capable of adjusting the flow rate with a 0 to 10 V input.
 Calculate the Cv value and select a valve that supports an appropriate rate.
 Select a valve of which the ratio of the maximum flow rate and the minimum flow rate will be at least 1:10.
 Place the three-way valve downstream of the pump. Connect one outlet to the heat exchanger.
Connect the other outlet to the lower part of the tank.
 Carefully read the instruction manual and use the three-way valve in accordance with the usage procedures.
MEES19K001
Three-way Pump
valve
Overview of system
This system has a pump provided at the outlet
of the tank and a three-way valve provided
downstream of the pump, and adjusts the flow
rate by controlling the opening and closing of
the three-way valve.
Flow rate
output device
Pump
Wiring 1-3 of CN512 of
connection control board
places (ON/OFF output)
Flow rate
adjustment
device
Three-way valve
Sub box
terminal block
No. 10, 11, 12
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