Installation Guide for VR2 Mounting bases 

 Rosahl membrane electric dehumidifiers

The VREG2 Series power adapter boards offer a simple and convenient way to convert a 5V USB supply to a 3V DC current limiting output. They are suitable for the Rosahl micro-dehumidifier membranes PD, RD, RS, M-1J, M-2J, M-3M, M-3J and MDL-3.

To simplify the VREG2 installation, three mounting base styles are avalaible to order:

The VR2-PMC is a simple 22mm barrel mounting module for the VREG2 USB-C power adapter board (order separately).

This simple VR2-FMC base-mounting module accepts the VREG2 USB-C power adapter board (order separately).

Installation Guide for VR2-PMC

VREG2 USB-C Power Adapter Board with VR2-PMC 22mm Barrel Housing

1. Components

The VR2-PMC barrel housing is purchased separately from the VREG2 adapter board. It consists of:

• Barrel housing (22 mm diameter)
• Internal locking ring (secures the VREG2 inside the barrel)
• External M22 locking ring (secures the assembly to the panel)

2. Cable Preparation

• Cut two 0.5 mm (~AWG 24) electrical cables (up to 0.5m due to volts drop).
• Solder cables to the VREG2 solder pads:
• Red cable → Positive (+) pad
• Black cable → Negative (–) pad

3. Board Insertion

• Orient the USB-C slot uppermost in the barrel moulding.
• Carefully slide the VREG2 board into the barrel using the guide slots.
• Press until the USB-C connector is flush with the front of the barrel.

4. Internal Locking Ring

• Pass the cables through the internal locking ring.
• Screw the ring into the rear of the barrel to secure the board.
• Apply a small amount of non-silicone sealant to the cable entry hole to reduce moisture ingress.

• ⚠️ Do not use silicone sealants — they permanently damage the membrane.

5. Cable Termination

• Fit cable crimps to the conductors.
• Ensure crimps are compatible with the membrane type.
• ⚠️ Note: M-Series membrane terminals use special alloys and are unsuitable for soldering.

6. Panel Installation

• Drill or prepare an 18.5 mm hole in the panel.
• Insert the barrel housing into the hole.
• Hand-tighten the external locking ring to secure the assembly.

Installation Guide for VR2-FMC

VREG2 USB-C Power Adapter Board with VR2-FMC Barrel Housing

1. Components

The VR2-FMC barrel housing is purchased separately from the VREG2 adapter board. It consists of:

• Flat mounting base and cover

2. Cable Preparation

• Cut two 0.5 mm (~AWG 24) electrical cables (up to 0.5m due to volts drop).
• Solder cables to the VREG2 solder pads:
• Red cable → Positive (+) pad
• Black cable → Negative (–) pad

3. Board Insertion

• Carefully position the VREG2 board into the base until flat.
• Ensure the USB-C connector is flush with the front of the barrel.
• Align cables with the exit slot at the end of the base.

4. Top Cover

• Taking care not to damage the cables press the top cover in place.
• Secure the top cover using the supplied M3 mounting screws.

5. Cable Termination

• Fit cable crimps to the conductors.
• Ensure crimps are compatible with the membrane type.
• The optional M-5PKT fixing kit includes terminal crimps for both M-Series and MDL-Series membranes

⚠️ Note: M-Series and MDL membrane terminals use special alloys that are unsuitable for soldering.

6. Panel Installation

• Drill or prepare two 3.5mm holes in the base plate.
• Fix in position using the M3 screws, nuts and washers supplied.

Installation Guide for VR2-RSM

VREG2 USB-C Power Adapter Board with VR2-RSM 35mm Barrel Housing

The VR2-RSM offers a compact mounting solution for the RS Series dehumidifier membranes. The 35mm barrel mounting holds both the dehumidifier and VREG power supply (order separately). It works with the RS1 or RS2 membranes. Caution: it is a difficult assembly and we recomment using the fully assembled version VR2X-RSM.for ease of installation.

1. Components

The VR2-RSM barrel housing is purchased separately from the VREG2 adapter board. It consists of:

• Barrel housing (35 mm diameter)
• Internal locking segment (secures and seals the VREG2 inside the barrel)
• External locking ring (secures the assembly to the panel)

2. Cable Preparation

• Cut two 0.5 mm (~AWG 24) electrical cables (up to 0.5m due to volts drop).
• Solder cables to the VREG2 solder pads:
• Red cable → Positive (+) pad
• Black cable → Negative (–) pad

3. Board Insertion

• Orient the USB-C slot uppermost in the barrel moulding.
• Carefully slide the VREG2 board into the barrel using the guide slots.
• Press until the USB-C connector is flush with the front of the barrel.

4. Internal Locking Segment

• Before fitting the locking segment, bend the cable through the slot on the left side below the rear of the VREG board.
• Lightly clean the bonding faces of the segment and housing with isopropyl alcohol or acetone and when dry, apply a small amount superglue to one of the bonding faces to secure it.
• Apply a small  quantity of non-silicone sealant to the cable entry hole to reduce moisture ingress.

⚠️ Do not use silicone sealants as they permanently damage the membrane.

5. Cable Termination

• Fit the correct cable crimps to the conductors after ensuring they are compatible with the membrane type.
• If needed, order a M-5PKT fixing kit which contains two cable crimps for the M-Series and two for the MDL Series membranes.

6. Panel Installation

• Drill or prepare a 36 mm clearance hole in the panel using a cutter or step drill.
• Insert the barrel housing into the hole.
• Hand-tighten the external locking ring to secure the assembly.