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Guide to maintaining and upgrading the Twinflex fire alarm system

Since its launch the Twinflex system has been instrumental in establishing the 2-wire market in the UK. Famed by allowing installers to develop a fire alarm system with simply 3 items; panel, multipoint detector with integral sounder and call point, the Twinflex quickly became the go to solution for electrical contractors.

Whilst the Twinflex has seen several changes over the years the good news is backwards compatibility has clearly been a priority. This means even if you have an original system you won’t be left holding the baby should the system need upgrading.

Original Twinflex V3 panel is faulty or a larger size panel is needed

All 3 versions of the original Twinflex panel are broadly referred to as Twinflex V3 panels. As per the current line-up these were available in 2, 4 or 8 zones, the 2 & 4 zone panels shared the same plastic enclosure whereas the 8 zone came in a much larger metal housing.

Product codes

  • 502 0002 – 2 zone Twinflex V3 panel
  • 502 0004 – 4 zone Twinflex V3 panel
  • 502 0008 – 8 zone Twinflex V3 panel

These panels began to be phased out in 2012 and today they are no longer available nor are any spare parts. Should your V3 panel require replacing and/or expanding then you would need to change the panel to the current TwinflexPro2. The good news is that the Pro2 will support the same cabling and devices.

Considerations when upgrading a Twinflex V3 to TwinflexPro2 panel

Physical size

The Pro2 panel is different in size compared with the V3 which may impact how the new panel has to be mounted.

TwinflexPro2 (2, 4 or 8 zones)Twinflex V3 (2 & 4 zone)Twinflex V3 (8 zone)
Width (mm)333313318
Height (mm)333263407
Depth (mm)999494

Conventional sounder and remote fire circuits

Both the V3 and Pro2 panels have conventional sounder/remote fire circuits so any existing conventional warning devices can still be supported however the end-of-lines are different. This means if your system utilises the sounder circuits you would need to find the existing EOLs and change the resistor to the versions supplied with the Pro2.


If you have an existing 2 or 4 zones V3 panel, then your system uses 2 x 2.1 Ah batteries which will not fit into the Pro2 equivalent. The new panel uses either 2 x 3.2 Ah or 7.2 Ah batteries.

Repeater panel

Both V3 and the current Pro2 panels support repeaters, however a Pro2 system will only work with the current 505-0010 repeater. Any existing V3 panels being upgraded will also need to replace the repeater.

Furthermore, the cabling between the main panel and repeater has changed. The V3 system used many cores which was typically achieved by either a single multicore cable or 2 x 4-core fire rated cable, compared with the current Pro2 repeater which requires 2 cores for data and a separate 2 cores for power. If the existing system used a single multicore cable, then this would only be suitable for power or data only due to the required segregation. This means either an additional cable needs to be run or the repeater powered locality with a suitable PSU.

Double gang metal relay module (part code 802-0001)

The Twinflex originally supported an output only relay which was housed in a metal double gang enclosure which required a separate power supply. This relay is not compatible with the Pro2 panel and therefore would need to be changed to the current 802-0006 module.

First generation TwinflexPro panel is faulty or a larger size panel is needed

The original TwinflexPro panel was introduced in 2011 and the following year replaced the original V3. Several years later this was re-engineered to become the TwinflexPro2. If you have a first generation TwinflexPro panel the following outlines your options should you need to expand or replace this panel.

TwinflexPro (first generation) panel needs expanding

Upgrading a 2 zone panel

Unfortunately, it is not possible to expand the 2 zone version which means replacing this with a 4 or 8 zones Pro2 is the only option.

Upgrading a 4 zone panel

The 4 zone panel however is compatible with the 505-0006 expansion card which will provide an additional 4 zones making 8 in total.

TwinflexPro (first generation) needs replacing

Replacing a first generation TwinflexPro with the current Pro2 is a fairly straightforward swap. Both panels are virtually the same dimensions and the Pro2 panel will actually fit directly onto the existing panel back-box with a small modification.

Considerations when upgrading a TwinflexPro (first generation) panel to TwinflexPro2

The only consideration is whether the existing panel uses a repeater. If this is the case, then this repeater will not be compatible with the Pro2 panel and therefore must also be changed.


The majority of the original Twinflex devices are still available today meaning direct replacements are available for each. The only exceptions are the following.

Original Multipoint detectors

The original Multipoint detector with sounder (202-0001) or detector only (202-0003) are no longer available having been discontinued in 2015. These were replaced by the Multipoint ASD range which also includes a version with sounder & beacon.

These are like for like replacements with the only consideration being the mounting base has changed. The ASD detectors are supplied complete with the new base so you will have everything required for the swap.

Discontinued part codeCurrent ASD part code
Detector only202-0003204-0003
Detector with sounder202-0001204-0001

Call point with integral sounder (part code 402-0007)

Historically a version of the Twinflex manual call point with integral sounder was available. These became end-of-life meaning any existing MCPs will need to be replaced by the standard version (402-0006). Following this replacement, the sound level in this area should be verified to ensure it meets the requirements.

Double gang metal relay module (part code 802-0001)

As outlined above the Twinflex originally supported an output only relay which was housed in a metal double gang enclosure which required a separate power supply. This relay is no longer available and would need to be changed to the current 802-0006 module.