Merlin CT1250
User Guide
Rev: 08 07-19
5
2.6
Fan current monitoring
There are two terminals on the circuit board, one detailed as
pictured [SUPP FAN LIVE] the other detailed [EXTR FAN LIVE].
If you are monitoring the fan by measuring the electrical
current going to the fan then these terminals should be used.
The live feed from the fan controller should be taken to the Merlin CT1250 and connected to
either the supply or extract side depending on which fan/s are being monitored - 20A max.
2.7
Potentiometers
[SUPP FAN LIVE] = [SENS1] Potentiometer
[EXTR FAN LIVE] = [SENS2] Potentiometer
The fan/s should be run at the minimum required
speed and the relevant potentiometer turned
slowly clockwise until the green LED on the circuit
board lights up. This indicates the panel has
detected the electrical current going to the fan.
If both supply and extract fans are being monitored both links of [FAN PD SWITCHES] (5) should
be removed. If only one fan is being monitored the relevant link should be taken out of this
terminal connection.
Do not overturn the potentiometer. Any damage may void your warranty.
2.8
Service Mode Switch
The service dip switch (if ON) can be used to allow the gas valve to remain
open for 4 hours without the fans running at each activation of the key.
At the end of the 4 hours the gas will shut off
