Mitsubishi Electric PAC-IF021B-E Manual page 25

4
Switch setting (FTC2)
4.5.3. DHW Heating Procedure
The heating of DHW tank is done in 2 stages, firstly the "Heat pump phase" followed by the "Electric heater phase".
4.5.3.1. Heat Pump Phase
The Heat pump phase for DHW mode, is used when the temperature difference between tank set temperature and
TH5 is either 10 deg C or 20 deg C (∆T
∆T is selected using Dip SW2-1
H
SW 2-1 Operation
OFF ∆T = 10 deg C
H
ON ∆T = 20 deg C
H
The heat pump will turn off or revert to heating when:
Tank temperature (TH5) > DHW set temperature consecutively for 1 minute.
Heat Pump Operation
The heat pump will be controlled directly by the FTC2 while in DHW mode. The operation characteristics can be selected using Dip SW2-2.
Option 1 – COP priority mode
In this mode the heat pump will heat the water over a slightly longer period of time with a controlled frequency, improving the coefficient of
performance. The result of this will be a more economical DHW 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
COP priority mode
OFF
(Operation frequency is controlled to have higher COP.)
Speed priority mode
ON
(Heat pump unit runs at the maximum frequency to reduce operation time.)
There is a 30 sec. delay in the Heat pump unit start to ensure the water circulation pump starts running before the Heat pump unit.
Other factors in the Heat pump phase
Water circulation
Heat pump status
pump status
ON for DHW ON
OFF for DHW OFF
4.5.3.2. Electric Heater Phase
Electric heater phase for DHW, is used when tank temperature (TH5) is less than DHW set temperature and the temperature increase is in
10 minutes is smaller than 1 deg C.
Electric heater phase will switch off when:
Tank temperature TH5 > DHW set temperature consecutively for 1 minute.
Electric Heater Phase Operation
The electric heater phase will vary dependent on the position of the heater within the heating circuit.
Electric heater phase TYPE A
Immersion
heater ON
Sanitary tank
TH5
Booster
heater ON
TH1
Booster
heater
Heat
pump
unit
Pump
ON
ON
The Dip switch settings for this operation are given in the following table.
SW 1-4
(Immersion heater) (Booster heater)
OFF OFF
(without IH) (BH for both DHW and Heating)
ON OFF
(with IH) (BH for both DHW and Heating)
OFF ON
(without IH) (BH for Heating only)
ON ON
(with IH) (BH for Heating only)
* BH : Booster heater IH : Immersion heater
)
H
3-port valve Booster heater 1
status status
ON Electric heaters are not used in the Heat pump
phase
OFF
Heat
Immersion heater
pump
unit
OFF
Radiator
Keep to
DHW circuit
SW1-5
(Immersion heater used)
No heater in DHW circuit
Booster heater 2 Immersion
status heater status
Electric heater phase TYPE B
Immersion
heater ON
TH5
Immersion heater
Sanitary tank
Booster
heater OFF
Booster
TH1
heater
Pump
Switch to
ON
Heating circuit
SW 2-7
ON
OFF
(Immersion heater not
used or only for Legionella)
TYPE A TYPE A
TYPE A TYPE A
No heater in DHW circuit
TYPE B No heater in DHW circuit
Flow temp. controller
Radiator
C-25 C-25