Mitsubishi Electric ecodan EHPT20Q-VM2EA Installation Manual page 10

4
Installation
Flow rate setting
Circulation fl ow rate of EHPT20Q-VM2EA unit is determined by settings of "Flow rate setting" and "pump speed".
1. Primary circuit for thermal store and space heating
In the space heating operation,circulation fl ow rate can be selected by main controller setting.(refer to page 36)
Pump 1 automatically operates to adjust the fl ow rate to the setting. Auto setting automatically selects a fl ow rate
appropriate for effective operation.
In the thermal store operation, circulation fl ow rate is automatically selected to adjust the hot water temperature to
the main remote controller setting and pump 1 automatically operates.
In other operations (ex. Freeze stat operation,Emergency mode,Indoor unit only operation), pump 1 operates at a
pump speed selected by main controller setting.(See Figure 4.3.2)
Adjust the pump speed setting so that the fl ow rate in the primary circuit is appropriate for the outdoor unit
installed.(see Table 4.3.1)
Outdoor unit Water fl ow rate range [L/min]
QUHZ-W40VA 3.0 - 8.0
<Table 4.3.1>
2. Primary circuit for hot water supply
Pump A automatically operates regardless of the fl ow rate the settings.
Water circulation pump 1 characteristics
160.0
140.0
120.0
100.0
80.0
60.0
Pump Speed 4(Default setting)
40.0
Pump Speed 3
20.0
Pump Speed 2
Pump Speed 1
0.0
0 2 4 6
Flow rate[L/min]
<Figure 4.3.2>
* The performance showing Figure 4.3.2 includes pressure drop of both cylinder unit and outdoor unit.
Before installation, please check if the maximum performance of water circulation pump 1 can accommodate the pressure
drop of external heating circuit.
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* If the water fl ow rate exceeds 9.0L/min, the fl ow speed will be greater
than 1.5m/s, which could erode the pipes.
* In case of "Compensation curve mode" or "Flow temp. mode" please
select "Manual" mode then choose fl ow rate manually from 3.0 to
8.0 L/min. If "Auto" mode is selected, fl ow rate will be fi xed at "7.0 L/min".
Pump Speed 5(Max)
8 10
4
Installation
Safety Device Connections
The primary pressure relief valves on the primary side needs appropriate discharge pipework.
Note: ● Do not secure the screws excessively when connecting the Discharge pipe,
otherwise this may result in damage to the cylinder unit.
● Pressure relief valve connections should not be used for any other purpose.
*1 In accordance with Building Regulations a tundish MUST
be fi tted into the pipework within 500 mm of the safety
device. Due to the distance between the two safety
devices it may be necessary to fi t each safety device with
its own tundish before you run the pipework together to a
safe discharge.(See Figure 4.3.3)
Diagram Description Connection Connection
part No. size type
10 Pressure relief valve G 1/2 Female
<Table 4.3.2>
Always refer to local regulations when installing discharge pipework.
Install discharge pipework in a frost-free environment.
It is necessary to provide appropriate drainage from the pressure relief valve situated on top
of the cylinder unit to prevent damage to the unit and the surrounding area from any steam
or hot water released. Relief valves MUST NOT be used for any other purpose.
10
DHW
Cold water inlet
10
Tundish
HEX
<Figure 4.3.3>
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