A fan coil unit (FCU) is a simple device consisting of a heating/cooling coil and a fan. It’s part of an HVAC system found in residential, commercial and industrial buildings. Heat is transported from a central heater/chiller to the individual FCU’s using water (like with traditional radiators).
Due to their simplicity, fan coil units are more economical to install than HVAC systems with air handling units.
Typically an FCU is installed in every room (comparable to the indoor units in a VRV system).
An FCU doesn’t measure temperature, so a TELETASK temperature sensor needs to be used e.g. from AURUS touch panel or a TDS12250 TELETASK temperature sensor.
The FCU does not have any build-in communication with the outdoor unit.
FCU’s can be divided into two types:
- 4-pipe systems
- Systems where there are different pipes for hot and cold water. This means that it’s possible to heat in one particular room and to cool in another at the same time. 4-pipe systems are mainly used in larger buildings (industrial, hotels, hospitals,…). So the fancoil unit uses two seperate valves to either allow the flow of cool water or hot water. The decision is made based on what is required at the present time. So in a 4-pipe system the FCU does know exactly in what mode it is in.
- 2-pipe systems
- Systems with only one set of pipes for hot or cold water. This means that the entire system is either in heating or in cooling mode. It’s impossible to heat in one room and cool in another at the same time. 2-pipe systems are mainly used in smaller installations (private houses) or climates where only cooling (or only heating) is necessary. In this system the FCU does not know exactly in what mode it is in. It will assume that the requested mode HEAT or COOL is what the current outdoor unit is configured in. Note that it is not advisable to use the auto heat cool mode in this situation.
To add a Fan coil unit interface to your TELETASK system, follow these steps:
- In PROSOFT Suite, go to the menu "Edit", "Outputs"
- Chose "New"
- Select "TDS13530 Fan coil unit interface" from the list of interfaces
- Enter a Name for the fan coil unit interface
- Enter the AUTOBUS address for the interface
- Enter a Name for the fan coil unit.
- System type: select ‘4 pipe system’ or ‘2 pipe system’.
- HVAC operation modes: Select the applicable modes for this FCU
- HVAC fan speed settings: Select the correct speed settings.
- Fan ON delay (heating): sets the delay between opening the heating valve and activating the fan. Use this setting to avoid that unheated (cool) air is ventilated in the room. This setting only applies in heating mode
- Fan OFF delay (cooling): Set the delay between closing the cooling valve and deactivating the fan. Use this setting to avoid freezing of the coil.
To configure and link a temperature sensor in PROSOFT with a fan coil unit, select ‘Fan coil unit’ as control method for the sensor and select the corresponding ‘Fan coil unit’.
If the selected fan coil unit has both ‘Heat’ and ‘Cool’ modes enabled, PROSOFT will automatically select that fan coil unit for the heating and for the cooling output of that sensor.