Mitsubishi Electric i-BX, Technical Manual

Page: 45 / 72

TM_i-BX(-N)_NC05_00_06_20_EN
MEHITS S.p.A. ● TECHNICAL MANUAL Version NC05 - Translation of the Original Instructions
45
ON
OFF
t
ON
OFF
ON
Compressor
Heater
step 1
Heater
step 2
OFF
Integral time for heater switching on
Actual water T
Heat pump regulation
setpoint
Heater switching on inhibition time
(0616
)
Heater switching on integral time
(0617
)
Heat pump regulation hysteresis x multiplication factor
(0507 x 0309)
Enable
Delivery heater
External air T (B4) [°C ]
Delivery heater
enable external T
(0304)
Delivery heater disable
hysteresis
(0305)
Disable
Once enabled, it’s activated based on the water temperature, in line with the following chart.
In integration mode, the heater works as follows:
it switches off when the system reaches the “regulation setpoint”, given by the value set in parameter 0153 , if the unit is set to fixed setpoint regulation,
or by the value determined by the compensation curves, if this type of regulation is enabled (for the details see the Hot offset paragraph) on the
inertial storage tank temperature probe B7 (only B7, and not the probe measuring the temperature of the system exchange output water - B2).
The heater will switch on again following the criteria described in the following cases:
when B7 ≤ “regulation setpoint” – 0507 x 0309 , if B2 has never reached a value equal to the “regulation setpoint”, without counting the possible time
delay 0616 (the delay refers to probe B2 and starts as soon as the same falls below the “regulation setpoint – 0507 ” irrespective of the value of B7).
when B7 ≤ “regulation setpoint” – 0507 x 0309 and B2 ≤ “regulation setpoint” – 0507 , counting the possible time delay, if also B2 has reached a value
equal to the “regulation setpoint.
If there is no storage tank, it will however be necessary to set parameter 0314 = YES in order to enable probe B7 (BT9), which will be positioned on
the system delivery.
The calculation of the integral time only starts after the time set in the “Heater switching on inhibition time” has elapsed (if other than 0);
the function of the above is to inhibit the switching on of the heater in integration mode, to allow time for the heat pump to warm up (for example, in
the case of start-up with cold water in the plant).
If the integral time for the switching on of the heater is
0617 = 0, step regulation will take place on the regulation setpoint and on the hysteresis value
0507 x 0309 .
In case of inhibition of the heat pump, the heaters will operate to replace it: see the “ Replacement heater ” paragraph.
For DHW production see the “ HP + DHW storage heater ( P0202 =3) or delivery heater “ paragraph.
In case of activation of the primary system flow switch, after the “flow switch alarm delay”, 1403 , the heater is disabled.
The heater operation is inhibited if the “Demand limit” (DI8) contact is active (see the “ DEMAND LIMIT ” paragraph).
Parameter 0304 is modified independently from parameter 0311 .