Toshiba Estia RUA-CP1701H, Service Manual

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Monobloc Outdoor Unit Service Manual
34
8.2.2.
Domestic hot water (DHW) operation
Mnemonic description:
•
DHW-S = domestic hot water temperature sensor
•
DHW-TT = domestic hot water temperature [P206]
•
DHW_stp = domestic hot water set point [P406]
•
dhw_dt = domestic hot water cylinder
ΔT (start) [P721]
i)
Operation start condition
When domestic hot water (DHW) is selected on the remote controller , and the following conditions are satisfied,
the DHW operation starts:
•
DWH Request dry contact is closed <OR > DHW_TT is below DHW_stp - dhw_dt <AND> Clock scheduling is
requesting DHW <OR > DHW Exception flag is set.
•
Summer Mode is active and cooling mode is satisfied.
•
Anti-Legionella Request Flag is set.
•
Unit is not currently defrosting.
•
DHW Only mode is selected.
ii)
Operation mode determination
The DHW operation mode is determined according to the temperature of the DHW-S sensor.
Heat pump operation
•
When DHW-TT < (DHW-stp – dhw-dt) the heat pump operation is selected
•
When DHW-TT
≥ (DHW_stp – 1K) the heat pump operation is stopped and the thermostat OFF status is
selected
iii)
Operation stop
The unit stops the DHW operation (or switches to Space Heating) if one of the following conditions occurs:
•
DWH Request dry contact is open <OR> DHW_TT is above CTRL_PNT – 1K
•
Max DHW duration time elapsed (DHW Max Runtime [P707] reached) for unit configured on water setpoint.
•
Max DHW duration time elapsed (DHW Max Runtime [P707] reached) <AND> SHC needs for unit configured
on air setpoint.
•
Clock scheduling is not requesting DHW anymore.
•
Anti-Legionella Request Flag is reset.
•
Exception Timer elapsed.
60°C
59°C
55°C
ON
OFF
ON
OFF
DHW_TT
DHW_stp
DHW_stp - 1K
DHW_stp -
dhw_dt
HP
HP
ON/OFF
Maximum DHW set point = 60°C