Hitachi RWM-(H)FSN3E, Service Manual

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7 Optional functions
SMGB0070 rev. 1 - 08/2011
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7
7.1.7 Step heater for 3-phase imbalance option
Only applies when power source of indoor unit is 3-phase (3N 400V 50Hz).
In order to prevent 3-phase imbalance by Heater Steps, this option will be used to switch all 3 steps at the same time.
When user allows 1-step heater mode (DSW3-3 ON), heater can only operate in one step.
3 stage ON
OFF
Required Load
Factor
5
7.1.8 Hydraulic separator combination
In some facilities, the YUTAKI S unit’s water pump is not sized for heating installation (small water pump). In this case, a
hydraulic separator or buffer tank and additional water pump (WP3) must be used to ensure proper water pump sizing.
When the boiler is configured to alternate with the heat pump, a hydraulic separator or buffer tank must be used to ensure
proper hydraulic balancing. Additional Water pump (WP3) and water sensor (Two3) are necessary for boiler combination
control.
User variables:
CODE Description Default Value
8-010 hsb Hydraulic Separator (Disabled, Enabled) Disabled
7.1.9 Secondary outdoor sensor accessory
Optional outside temperature sensor: an outside temperature sensor can be directly connected to the controller if the heat
pump is located in a position that is unsuitable for this measurement.
If a wired outside sensor is selected (DSW4-2 ON), use the wired outside temperature instead of the Outdoor unit outside
temperature.
N O T E
For more information refer to 2nd ambient temperature sensor (ATW-2OS-01 7E549909).