The Merlin CT1250 ventilation interlock system, with built in current
monitoring, is designed specifically for use in commercial kitchens to
meet BS6173: 2001, which is now a much-recognised standard in the
This panel is to be used when the kitchen appliances do have flame
failure devices, therefore Gas proving is not a requirement.
The Merlin CT1250 acts as an interlock between the ventilation system
and the gas solenoid valve. The system has a built in power monitor
which is a method used for interlocking a kitchens gas supply with the
ventilation system. As an alternative to pressure differential switches
the CT1250 is designed to monitor the electrical current going to a
ventilation fan. When the fan is turned “on” the
CT1250 monitors the electrical current going to the fan motor, when
there is sufficient current going to the fan motor our panel receives a
signal to indicate the fans are operating. Turning the key to the
“on” position will open the gas solenoid valve. If
the fans should fail, the “fan fault” LED on the
panel will illuminate and the gas solenoid valve will close.
When there is a “fan fault” the supply fan or
extract fan led on the Merlin CT1250 panel fascia will flash. This
informs the electrician or kitchen staff which fan has failed.
Operating the system in the above manner will ensure the requirements
of BS6173: 2001 are fully met where all the catering equipment has
flame failure devices fitted.
Installation for the Merlin CT1250 is easy as there is no calibration.
Wiring of the system is straightforward using volt free connections for
all BMS and remote emergency stops. A corgi-registered installer would
be required to fit the gas solenoid valve. All panels and gas solenoid
valves supplied by S&S Northern carry a full 3-year
Calibration of the current monitor is easy, once wired set the fan
speed controller to setting 1 (or low setting) for example. Turn the
blue rotary switches anti-clockwise until the green LED goes out, then
slowly turn clockwise until the green LED is again illuminated. This
will give you the minimum current requirement, if the fan is turned off
the LED will go out, send a signal to the Merlin panel, which will in
turn shut off the gas.
Key features of the Merlin CT1250
• Allows Compliance with BS6173: 2001 for commercial kitchens
• Clear LED display for system indications
• Complete all in one box
• Can be used when pressure differential switches cannot be
used e.g. wall-mounted fans
• Reliable method of interlock, with no moving parts
there’s little to go wrong
• Straightforward to install and calibrate. The CT1250 can be
easily adjusted to the users requirements
• This method is not recommended with belt driven fans
• Easy installation
• BMS Terminals Normally Closed or Normally open and common.
• Will accept remote emergency shut-off buttons
• Three year warranty
• All Merlin systems are designed to comply with the latest CE
requirements and low voltage directives