[Hcl21] Hot water heating coil, temperature-controlled
Program block, name / node subtype: [Hcl21] Hot water heating coil, temperature-controlled
Library hierarchy: Ventilation and air conditioning equipment
Family: Hcl
Project tree | Diagram |
|---|---|
|
|
|
Configurator
Program blocks are stored in the library without I/Os. Use the auto-create and auto-connect functions to create I/Os and/or to connect them to the interface blocks, e.g., R_A, CMD_B. Alternatively, take the I/Os from the folder containing the predefined I/Os in the library and/or from the plant and connect them to the interface blocks.
Controls the supply air temperature (heating) by changing a valve position and by switching an optional pump.
There is a delay off time for the signal for the operating state that keeps its value to "True" after the heating coil becomes inactive (both operating states of the valve and the optional pump equal to "False") which, unlike an electrical heating coil or a cooling coil, must be kept low, e.g., 5 seconds, to not delay the switching-off sequence of CMDSEQ_B, if used in an air handling unit plant (which is most likely the case).
This program block has the following optional functions:
Option: Frost protection (1xBI, 1xAI)
Performs frost protection (FrPrt21).
Delete this option if this coil is used as a reheater.
Option: Pump (1xBO, 4xBI)
Controls a pump (Pu21). Different alternatives are possible, e.g., TwnPu21.
The pump starts when the valve is active (valve position over a specific value, e.g., 4 %) and stops with an optional delay when a valve is inactive (valve position below a specific value, e.g., 2 %).
Option: Disable heating at high outside temperature
Heating is disabled above a specific outside air temperature, e.g., above 18 °C.
Delete this option if this coil is used as a reheater.
Option: Disable temperature control in case of dehumidification
Provides an interface (most likely to the cooling coil) and logic to disable the temperature control in case of dehumidification to not preheat the air when the cooling coil performs dehumidification.
Delete this option if this coil is used as a reheater.
Option: Do not generate disturbance signal switching off the plant at high outside temperature
To increase the availability of the air handling unit at high outside temperature, the generation of a disturbance signal that switches off the plant is disabled, and the plant continues running in the event of an alarm from the heating coil.
Option: Flow temperature (1xAI)
Creates a flow temperature.
Option: Hot water demand
Generates a signal that hot water is demanded. This is typically read by the functions for hot water supply coordination, e.g., SplyHw21, SplyHw22.
There is a delay off time for the hot water demand.
Option: Pump activation at low outside temperature
Starts the pump at low outside temperature, e.g., below 4 °C, even if the coil is not running.
This improves the frost protection.
Option: Return temperature (1xAI)
Creates a return temperature.
Option: Support for purge
Provides an interface and logic to open the valve at 100 % during startup purge and a ramp to close the valve from 100 % to 0 % within a given time, e.g., 5 minutes. Most likely the valve does not go back to 0 %, because the temperature control takes over.
Delete this option if this coil is used as a reheater.
Option: Switch-off delay for pump
Switch-off delay for the pump when the valve was active.
The pump stops without delay if there is a signal for exception from a superior logic (plant level).
Name | Description | Type | Alarm / Notification class | Trend / Type |
|---|---|---|---|---|
Vlv | Valve | N/A | N/A | |
TCtr | Temperature controller | Ctr: Controller | N/A | N/A |
Name | Description | Type | Alarm / Notification class | Trend / Type |
|---|---|---|---|---|
Pu | Pump | N/A | N/A | |
FrPrt | Frost protection | N/A | N/A | |
HwDmd | Hot water demand | BCalcVal: Binary calculated value | No | No |
TFl | Flow temperature | AI: Analog input | Yes, 4 | Yes, 2 |
TRt | Return temperature | AI: Analog input | Yes, 4 | Yes, 2 |
Description |
|---|
Pump activation at low outside temperature |
Switch-off delay for pump |
Disable heating at high outside temperature |
Do not generate disturbance signal that switches off the plant only at high outside temperature. |
Support for purge |
Disable temperature control in case of dehumidification |