Setpoint Regulators; Hot Offset - Mitsubishi Electric i-BX-N Technical Manual

TM_i-BX(-N)_NC05_00_06_20_EN
4.2

SETPOINT REGULATORS

i-BX-N units will be able to regulate system water production in a "traditional" manner - which means on the basis of a fixed setpoint that can be set
by the user -, or in an "advanced" manner - based on a dynamic setpoint calculated through climatic curve managed functions -, both as far as cold
and hot, as described below.
By setting parameter 011D Ambient influence on unit regulation= "PRESENT", it will be possible to drive the unit to adjust based on the water
temperature, only in case of ambient hot/cold request-, on the basis of the ambient setpoint set on the N-THC, by at least one of the zones configured
in a system (with the ambient setpoint met, the machine pump will switch off both if set to sniffer and continuous operation).
If all the zone setpoints are met, the unit will not switch the compressor on, even with the water temperature far from the setpoint and outside the
regulation hysteresis. In this case, the compressors will only come back on when a hot/cold request is coming from at least one of the system zones.
By setting the parameter 011D Ambient influence on unit regulation= "NONE" (default value), the unit will adjust in the traditional manner only on the
water temperature, therefore without being affected by the room temperature.
If zone control is disabled, meaning 016A = "No", parameter 011D is forced to "NONE" and cannot be changed.
For the default values of the various parameters, see the parameters table
4.2.1

HOT OFFSET

When the system is set to heating, the delivery water temperature is calculated based on the climate curves defined following the function described
in the following chart. The x-axis shows the external temperature, the y-axis the delivery water temperature.
This function can be enabled or disabled using parameter 0152.
Climate curve selection
Delivery setpoint with ambient 20°C
External temp. in °C
The diagram in the figure shows the trend of the climatic curves relating the required heating setpoint for the water delivered to the systems to the
external temperature values (calculated external temperature average).
The curve, selected based on the characteristics of the building and the ambient heating system, can be changed by adding or subtracting a value
(Offset) that "moves" it vertically; it may also be rotated, by adding or subtracting a value to 20°C of external temperature (Offset at 20°C) that "rotates"
the curve around an ideal axis on the -20°C external temperature point, therefore correcting an undesired behaviour at the milder external
temperatures (see following diagrams).
In addition to the system curve, which determines the value of the general temperature of the water delivered to the users, there is a specific climate
curve for each low temperature zone, which determines the value of the delivery temperature for the water of the mixed circuit.
The system and zone curves work in cascade. Therefore, the climate curve of the mixed zone cannot request a value higher than that supplied by
the system curve.
32
MEHITS S.p.A. ● TECHNICAL MANUAL Version NC05 - Translation of the Original Instructions