Sensors And Actuators; Safety Cut-Off Switch (High Limit); External Reset Input; On Board Alarm Led - Honeywell S4965V3250 Functional Description

Title: Functional description S4965V3250

5.7 - Sensors and Actuators

5.7.1 - Safety Cut-off switch (High Limit)

The safety cut-off switch (also called High Limit switch) prevents the system from being damaged by overheat.
- This switch is in fact the last stop to the ignition control if the appliance is overheating itself. Overheating can be
caused for example by a bad connected temperature sensor or a low water situation.
- This switch is normally closed and opens only if the overheat condition occurs. The controller reads continuously
the status of the switch and immediately activates the lockout state if the switch opens due to whatever reason.
A manual action is required to release the controller from the lockout state. This can be done by the on board reset knob or
external reset button or by the Modbus communication message.

5.7.2 - External reset input

Once a non-volatile lockout occurs, reset can be performed (with max.5 reset in the last hour) by using a remote switch.

5.7.3 - On board alarm LED

The on board alarm LED is used to indicate an Error/Fault condition state:

If there is a blocking error, LED is lighted blinking (1s period).

If the boiler is in any lockout error, LED is on.

Otherwise, no error in the system, LED is off.

5.7.4 - On board reset knob

The on board Reset Knob - button can be used to reset the lockout error. There is no limitation in term of lockout resets
made by this button.

5.7.5 - Gas Valve

The gas valve which must be connected to the Basic ESYS controller is a CVI-m valve. An example of such a valve is the
VK41xxFxxxx or VK41Vxxxxx. There are many other valves which can work together with this ESYS. For more information
about gas valves, please contact the appropriate department or your local Honeywell affiliate.

5.7.6 - Alarm output

Alarm output is set whenever a lockout or blocking condition occurs.
The electrical specification for the Alarm output is described in the table below.
Voltage
230 V AC

5.7.7 - Burner On output

Burner On output indicate whenever the boiler is running (gas valve is opened previously, flame read and validated
successfully). The electrical specification for the Burner On output is described in the table below.
Voltage
230 V AC
First issue.
SW update and add parameter into list ModBus communication.
Current Special
Cos φ >= 0.6
0.4 A
Current Special
Cos φ >= 0.6
0.8 A
Description
Heating & Cooling Appliance Controls
Doc.: S4965V3250E20
Sign. E.C.N.
I.Mariscak 0131527
I.Mariscak
Honeywell
Date Rev.
27-Jun-2016 A
03-Aug-2016 B
Page 17/33