Compact natural ventilation control
The D+H PS-VFM1 is a compact natural ventilation controller for operating one group of compatible 24 V DC window drives.
It combines the power supply and control functions within a small module designed for installation in a suitable indoor junction box.
The PS-VFM1 is a controller, not simply a power supply. It accepts an open and close ventilation switch and can support an optional rain sensor or wind and rain sensor.
Replacement for the D+H VCM 05U
The PS-VFM1 is the current replacement for the previous D+H VCM 05U natural ventilation controller.
Where an existing VCM 05U is being replaced, the connected drive load, switching, sensor arrangement, junction box, wiring and available access should be checked before installation.
Typical applications
- Small automated window systems
- Single natural ventilation groups
- Local window-control installations
- High-level windows requiring wall-switch operation
- Natural ventilation systems with optional rain sensing
- Replacement of an existing D+H VCM 05U controller
Control functions
- Controls one natural ventilation group
- Open and close wall-switch operation
- Connection for an optional rain sensor
- Connection for an optional wind and rain sensor
- External control input
- 24 V DC output for compatible window drives
Technical information
| Product type | Compact single-group natural ventilation controller |
|---|---|
| Supply | 230 V AC, 50 Hz |
| Power consumption | 30 VA |
| Output | 24 V DC |
| Rated drive current | 0.7 A |
| Maximum short-duration current | 1 A for less than 10 seconds during one operating cycle |
| Operating duty | Short-time duty, 20% / 10 minutes |
| Ventilation groups | 1 |
| Protection rating | IP30 |
| Operating temperature | 0°C to +50°C |
| Housing | Plastic |
| Dimensions | 50 × 48 × 28 mm |
| Installation | Within a suitable indoor junction box |
Rated current and drive selection
The PS-VFM1 should be selected using its rated drive current of 0.7 A.
It can provide up to 1 A for less than 10 seconds during one operating cycle, but it should not be treated as a continuous 1 A controller. The connected drive load and actuator starting current must be checked before selection.
Switches and weather sensing
The PS-VFM1 can be operated from a compatible open and close ventilation switch.
It can also be connected to a suitable rain sensor or wind and rain sensor so that connected windows can be commanded to close when adverse weather is detected, while mains power remains available.
Where several PS-VFM1 controllers are connected to a common rain sensor, the wiring arrangement must follow the D+H connection requirements.
Mains power failure
The PS-VFM1 does not include standby batteries.
If the connected windows are open when the 230 V AC mains supply fails, they will remain in their existing position because the controller no longer has power to operate the drives. A connected rain sensor cannot close the windows while the controller has no operating power.
Where automatic close on loss of mains power is required, use a battery-backed D+H RZN or CPS-M control panel.
Natural ventilation only
The PS-VFM1 is intended for normal natural ventilation and automated window operation.
It must not be used as a substitute for a smoke and natural ventilation control panel where openings must respond to a fire alarm, perform a smoke-control function or remain available from standby batteries during a mains failure.
Installation and coordination
The controller location must provide suitable access for electrical connection, testing and future maintenance.
Selection and installation should account for:
- connected drive model and quantity;
- rated and starting current;
- wall-switch requirements;
- rain or wind and rain sensor connections;
- junction-box size and location;
- 230 V AC supply requirements;
- 24 V DC drive cabling;
- cable length and voltage drop; and
- access for commissioning and service.
Compare natural ventilation controls
The PS-VFM1 is one of several D+H options for natural ventilation control.
Compare the PS-VFM1, PS-VE power supplies and GVL natural ventilation control panels
EBSA technical support
EBSA can assist with confirming drive compatibility, connected load, switching, weather sensing, wiring coordination and the appropriate control arrangement for the project.
