Mitsubishi Electric ecodan PUHZ-W50VHA2 User Manual page 35

Domestic hot water (DHW) off condition
Domestic hot water can be selected in 2 ways
Pattern 1.
An external input or remote controller is used to switch to domestic hot water mode.
Domestic hot water pattern 1 will turn off when the domestic hot water tank reaches set temperature consecutively for 1
minute. Then the Ecodan will turn off.
Pattern 2.
Automatic change over mode or an external input (e.g. Local timer signal received must last > 5 seconds) is used to switch to
domestic hot water mode.
Domestic hot water pattern 2 will switch off under the following conditions:
A) The domestic hot water tank reaches set temperature THW consecutively for 1 minute
B) The system has been in domestic hot water mode consecutively for Htime (minutes)
System operation status at start-up
First power-on
First starting up after initial filling up
TH5 <25°C (tank temperature is low)
Others
Domestic Hot Water Heating Procedure
HEAT PUMP PHASE
The heat pump phase for domestic hot water mode, is used when the temperature difference between tank set temperature and
TH5 is either 10°C or 20°C ( TH)
SW2-1 Operation
OFF TH = 10°C
ON TH = 20°C
Usually with inverter type outdoor unit, the operation frequency is reduced as it approaches the set temperature to keep it
constant. In domestic hot water mode, the co-efficient of performance gets worse and operating times become longer if the
operation frequency is reduced. Therefore in domestic hot water mode, the frequency shall be controlled by the FTC2, not the
outdoor unit.
TH selected using Dip SW2-1
The heat pump will turn off or revert to heating when:
Tank temperature (TH5) > domestic hot water set temperature consecutively for 1 minute.
Heat pump operation
The heat pump will be controlled directly by the FTC2 while in domestic hot water mode. The operational characteristics can be
selected using Dip SW2-2
Option 1 COP priority mode
In this mode Ecodan will heat the water over a slightly longer period of time with a controlled frequency, improving the COP.
The result of this will be a more economical domestic hot water heat up.
Option 2 Speed priority mode
In this mode the heat pump will run at maximum frequency during DHW heat up. The result of this will be a reduced time to
heat the tank but also a reduction in COP and so an increase in energy consumption.
SW 2-2 Operation
OFF COP Priority mode: Operation frequency is controlled to have higher COP.
ON Speed priority mode: Heat pump unit runs at the maximum frequency to reduce operational time.
There is a 30 second delay in the Ecodan start to ensure the water circulation pump starts running before the Ecodan. When the
Ecodan unit stops running, the pump will stop at the same time in order to avoid the tank releasing the internal heat.
INSTALLATION: FTC2
Htime (minutes)
Table 1.9
As shown in the table, Htime becomes longer
when the water temperature in the tank is low.
This is to delay the operation switchover to
300
Heating mode.
Table 1.8
180
32
ase
Table 2.0
33