Normal Thermo-On/Off Operations; Thermo-On/Off Temperature Conditions - Mitsubishi Electric CAHV-P500YA-HPB Service Handbook

[ VII Control ]

2. Normal Thermo-ON/OFF operations

DIFF1 = 2 ºC (Initial setting): "1015" Digitally set value
DIFF2 = 2 ºC (Initial setting): "1016" Digitally set value
Tmax (Outside temperature
Single/Multiple
system
Built-in
thermistor
Individual
system
Representative
water
temperature
Representative
Multiple
water
system
temperature

1) Thermo-ON/OFF temperature conditions

Intlet-temperature-based water temperature control in an individual system (with the external water temperature sen-
sor setting being set to ON and the Inlet-/outlet-based control option being set to inlet)
Inlet water
temperature changes
Outlet-temperature-based water temperature control in an individual system (with the external water temperature
sensor setting being set to ON and the Inlet-/outlet-based control option being set to outlet)
Outlet water temperature
changes-2
Outlet water temperature
changes 1
The unit will restart when the inlet water temperature
drops from the inlet temperature at the time of
Thermo-OFF by more than the value set for DIFF2.
HWE10060
≤
-10 ºC: 65ºC, Outside temperature > -10 ºC : 70ºC)
Thermo-ON
sensor
conditions
Inlet-water-temper-
ature-based control
Outlet-water-tem-
perature-based
control
Water temperature
control based on the
external water tem-
perature reading
Water temperature
control based on the
external water tem-
perature reading
Thermo-OFF temperature
DIFF2°C
Preset water temperature
Thermo-OFF temperature
DIFF2°C
Preset water
temperature
Thermo-ON
conditions
Inlet water temperatures is low-
er than the "Inlet temperature
at Thermo-OFF - DIFF2ºC"
and the system is not in the
short-cycling protection mode.
Inlet temperatures are below
the "Inlet temperature at Ther-
mo-OFF - DIFF2ºC"AND the
average outlet temperature is
at or below "Preset tempera-
ture + DIFF2ºC" AND the sys-
tem is not in the short-cycling
protection mode.
Inlet water temperatures is low-
er than the "Inlet temperature
at Thermo-OFF - DIFF2ºC"
External water temperature
thermistor reading < Set tem-
perature - DIFF 2 value (ºC)
AND the anti-short-cycling pro-
tection function is not been trig-
gered.
The number of units to run an
optimal operation will be deter-
mined by the main unit.
(The unit with the least amount
of cumulative operation hours
will go into operation first.)
When the water temperature is controlled based on the inlet
temperature, compressor frequency will be controlled as
described in section -3- "Compressor frequency" (page 80).
(Automatic operation according to the preset temperature)
When the water temperature is controlled based on the
external water temperature sensor reading (outlet water
temperature), compressor frequency will be controlled in the
way that the target water temperature will be maintained. If
there is a sudden increase in water temperature and the unit
did not stop at the preset temperature, the unit will stop when
the temperature that equals "the preset temperature + the
value set for DIFF2" is reached.
- 90 -
Thermo-OFF conditions
Inlet water temperatures are
greater than the "set tempera-
ture + DIFF2 value (ºC)" AND
at least 60 seconds have
passed since the last Thermo-
ON.
Average outlet water tempera-
ture is greater than the "set
temperature + DIFF2 value
(ºC)" AND at least 60 seconds
have passed since the last
Thermo-ON.
External water temperature
sensor reading is greater than
the "set temperature * DIFF2
value (ºC)" AND at least 60
seconds have passed since
the last Thermo-ON.
External water temperature
sensor reading is greater than
the "set temperature * DIFF2/2
value (ºC)" AND at least 60
seconds have passed since
the last Thermo-ON.
The number of units to run an
optimal operation will be
determined by the main unit.
(The unit with the least amount
of cumulative operation hours
will go into operation first.)
GB