3 REF7090520 REF7090521 Fan-coil controller for wall mounting 578 REF7090522 REF7090523 REF709052x Pulse width modulated (PWM) valve outputs for thermal actuators, AC 230 V P or PI control behaviour selectable 3-speed fan control, automatic and manual Manual switching between heating and cooling operation or automatic with changeover (C/O) sensor QAH11 Potential-free input for window contact or occupancy detector Inbuilt room temperature sensor Three operating modes: Comfort / Economy / Standby The st
Application For controlling the room temperature in individual rooms and zones which are heated and cooled by fan-coils. The controllers are suitable for 2- or 4-pipe applications with manual and automatic fan control. They control: • a 3-speed fan • either two valve actuators for 4-pipe applications • or one valve actuator and an electric heater for 2-pipe applications.
Technical design Controller The room temperature is measured by an inbuilt sensor and compared to the actual set-point. According to the resulting deviation, the processor calculates the pulse duration ratio for controlling the thermal valve actuators and, if necessary, for controlling the electric heater. In addition, if the selector switch for the fan speed on the controller is set to "Auto“, the optimum fan speed is defined automatically.
Control Sequences Y [%] 4-pipe fan-coil P09 = OFF or 0 YH YK 100 80 3574D02 50 QH Xp WH WK Xdz QK Xp Note that if P04 = ON or 1, then the heating output YH can be used to control a radiator heater which is external of the fan coil. In this case he fan stops in the heating sequence. Return air sensor If the controller is set to a 4-pipe system (P09 = OFF or 0) then an external sensor (return air sensor) can be connected to the terminals B2, M. The sensor must be of the type QAH11.1.
Changeover between heating and cooling operation Controllers for 4 pipe fan-coils change automatically between heating and cooling. Controllers for 2 pipe fan-coils need information about the water temperature. They receive this information either from a water temperature sensor (changeover sensor) or from a remote central station or from the operator through the C/O (changeover) key.
Window Contact Input Settings The window contact input (DU1, GND) is used to switch the operating mode from normal mode (defined by P01) to reduced mode (defined by P02). The idle position of the contact is defined by P03. Security The window contact input is separated from 230V and is SELV (Secure Electric Low Voltage). No additional power supply is needed for detecting the position of the external contact (the current necessary is delivered by the controller).
Fan Operation Neutral zone When the fan is automatically controlled (manual fan speed selector switch on the controller set to "Auto“) then in the neutral zone (control-free zone) of the normal operating mode the fan remains either constantly on or is switched off after 2 to 3 minutes. The actual behaviour is defined by P08. In the reduced mode the fan is always switched off in the neutral zone.
Electric heater The REF7090521, REF7090523 controllers have a relay built in for directly controlling an electric heater. The REF7090520, REF7090522 controllers need an external relay with a 230V coil for this purpose. Note that this relay is not included in the delivery. The controller must be configured as a 2 pipe controller (P09 = ON or 1). The controlling of the heater depends on the control deviation (pulse duration modulated).
Parameter table Nbr.
(3) (4) (5) All controllers can be set to either 2 or 4 pipe controllers. The difference between the REF7090521 or REF7090523 and the REF7090520 or REF7090522 is the relay instead of the second valve output. The default setting of P09 and P10 for REF7090521 or REF7090523 is "ON" or 1 and for REF7090520 or REF7090522 "OFF" or 0. If the REF7090520 or REF7090522 controllers are used to control an electric heater, then an external relay must be used and P09 and P10 must be set accordingly.
4-pipe fan-coil L T B2 L S1 M DU1 SELV REF7090520 REF7090522 N Q1 Q2 Q3 3 N Y10 N Y1 Y1 M1 760 VA max. N GND 3576D01 AC 230 V / 50/60 Hz B2 Y10 3.5 VA max. 3.5 VA max. With 4-pipe applications (P09 = OFF or 0), a return air sensor QAH11 can be connected to terminals B2-M . In this case, the inbuilt sensor is automatically deactivated. 2-pipe fan-coil The c/o or return air sensor input (B2, M) is internally in the controller connected to the mains supply voltage of AC 230 V.
Project engineering and wiring notes • Wiring, fuses and earthing must be installed in compliance with local regulations. It must be made certain that safety extra low voltage lines (SELV circuits) are clearly separated from AC 230 V mains voltage cables (also refer to Installation Instructions G3573X) • The cables to the controller, external sensor, fan, valves and to the electric heater carry AC 230 V and must be appropriately dimensioned.
Safety instructions: Important If an electric heating element is connected to the controller then the installation must comply with the safety regulations EN 60 335-2-73. Safety check If any safety device of the installation activates an interrupt, then the installation must be thoroughly checked before the system is reset and put back into operation. Important The controller may be opened only when isolated from the mains supply.
Technical data Power supply Operating voltage L, N AC 230 V ±10 % Frequency 50 /60 Hz Power consumption 3VA (without field devices) Fuse or circuit breaker in supply lines max. 10 A Over-voltage category III Electrical connections Max. cross-sectional area per terminal 2 wires each with 1.5 mm2 or 1 wire with 2.5 mm2 Outputs Fan control Q1, Q2, Q3 AC 230 V Max. load, cos ϕ > 0.9 AC 3.3 A (note 1) Type of automatic action according to EN60730 1.B Electric heater Q14 AC 230 V Max.
Low voltage directive 73/23/EWG Electromagnetic compatibility Immunity to interference EN 61000-6-1 Emissions EN 61000-6-3 Product safety Automatic control devices for use in the home and similar applications Special requirements for energy controllers Housing Colour EN 60730-1 EN 60730-2-11 RAL 9010 Note 1: The total amount of all output currents plus the supply current of the controller must not exceed 10A, which is the allowed maximum value for the fuse in the supply lines.
/16 Building Technologies HVAC Products ©2005 Siemens Switzerland Ltd Subject to change Fan-coil controller for wall mounting ACR12 CE1N3578en 03.10.
