KEY RK-2001E2, Operation Manual

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4.4. Boiler overheating protection.
Boiler overheating temperature [A 99] – value, exceeding which causes permanent
turn off of the pressure fan and launch of the circulating pump, to prevent boiler
overheating. Overheating mode is indicated by boiler overheating indicator and by
displaying error [E 2] on the display. It can be turned off by pressing STOP button, but
only when temperature decreases below boiler overheating temperature. Pressure fan
turning off occurs also in case of damage of the boiler temperature sensor, which is
displayed on the display by error [E 1] .
STB – the controller has also additional protection from overheating, which is
independent from the processor, . In case of temperature increase over 95°C, the
control process is turned off by turning the fan off and launching the circulating pump.
The fan and the pump are joined to the control process again, when temperature
reaches 89°C. STB circuit enables more precise boiler work control and reduces
overheating possibility.
4.5. No fuel.
No-fuel testing time during fuel firing start [Fd60] – after switching to WORK mode,
if water temperature does not increase by 2°C in programmed time, the control
process will be turned off and the display will show the message: [FUEL] . You can
return to previous mode by pressing STOP button. No fuel testing time during fuel
firing is finished after the set temperature is achieved.
No-fuel testing time during work mode [Fb30] – in WORK mode, if temperature of
water in the boiler decreases below temperature set with the thermostat, by hysteresis
value, and does not increase by 2°C in the programmed time, the control process will
be turned off and the display will show the message: [FUEL] . You can cancel the
alarm by pressing STOP button.
4.6. Additional output.
Additional output work mode [Ar 0] – the controller is equipped with a multipurpose
output that can work in one of following modes:
[Ar 0] mode – output may control oil or gas boiler if such boiler exists in the heating
circuit. After switching the controller on with the main power switch, the additional
boiler is turned off and it turnes on again when there is no fuel in the solid fuel boiler.
This function is useful in heating systems where the solid fuel boiler is used to cut
heating costs. After erasing no fuel alarm by pressing STOP button, the additional
boiler is again turned off and the controller works again.
[Ar 1] mode – output may control additional alarm signaling system. Boiler temperatu-
re sensor malfunction, overheating or no fuel alarm will turn on the additional alarm.
[Ar 2] mode – output may control mixing valve servo-motor. Controlling the mixing
valve requires room thermostat to be connected to the controller. The mixing valve is