Be172 Installation Manual Web Version
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Be172 / Be172B Installation Manual / Rev.5-2026
| KEY START MODULE BE172 Specifications | |
| DC Supply / OFF mode current | 6V up to 30 Vdc / 8mA |
| Static Outputs (short circuit proof) | 150 mA DC |
| Key Switch Rating | 30 A (15 secs) |
| Dimensions / Cut-out | 72X72X55 mm / 68x68mm |
| Case/Weight | Steel powder-coated / 390 gr |
| Operating Temperature /H.R. | -30° C /+70° C / 95 n.c. |
| Mounting /Ingress Proetction | Two clips / IP54 |
KEY START MODULE DETAILED DESCRIPTION
The Be172 includes the basic safeguards to protect a diesel or gasoline engine. It features a 4-digit military-grade 7-segment display, 3 static outputs, 7 digital inputs, and a 30Adc-rated key switch. The Be172 monitors an oil pressure switch, a temperature switch, a fuel level switch, a charger alternator voltage and auxiliary alarms. The Be172 provides a MANUAL mode of operation. Four adjustable settings about pre-glow, fuel solenoid, fuel alarm and auxiliary alarm allow you adapting the controller to your machine. The display indicates ENGINE HOUR COUNT, BATTERY VOLTAGE, ALARMS, and SETTINGS. The key-switch features auxiliary normally closed contact. The version with a normally open auxiliary contact is only optionally available (see section 5.0).
1.0 KEY START and KEY STOP
- A) - When the KEY is in position ‘OFF’, a white dot blinks on display indicating a standby mode. By turning “ON” and ‘OFF’ the key, the display indicates the [HOUR COUNT] for a few seconds. The ‘OFF’ mode clears all alarms.
- B) - Turn the KEY to ‘ON’. The display indicates the battery voltage for 3 seconds.
- C) - When the display indicates the message [StA-], turn the KEY to ignition. When the Be172 detects oil pressure or voltage on the charger alternator, the display indicates the status of the HOUR COUNTER and then a rotating animation of display segments. If you programmed a pre-glow, the [ПППП] message will appear as soon as you turn the key on. After that, you can start the engine.
If you leave the KEY in the on position, without starting the engine, the Be172 shuts down the fuel output; the display will indicate the message [FAIL].
Note1 In normal conditions, when the engine is not running, the Be172 expects an oil pressure switch closed and no voltage on D+ terminals. If the Be172 detects otherwise, it will warn you by indicating for a few seconds the messages [oil.], [cHAr.], or both in sequence. You can start the engine without problems; the Be172 only reminds you to investigate the issue.
- D) - Turn the KEY to ‘OFF to stop the engine. The display will indicate for 10 seconds the [HOUR COUNT]. Then, it will shut down the display. A white dot on the right side will blink slowly, indicating a standby status. The Be172 absorbs as low as 8mA of current. Consider removing the battery connection if you do not use the engine for a long period (e.g. weeks or months)
2.0 KEY START ALARMS LIST
| [DISPLAY] | ALARM DESCRIPTION | NOTES |
| [bELt] | Engine Belt break or Charger failure shutdown. The Be172 triggers this alarm and shuts down the engine if the input [D+/W.L] is continuously missing for over 20 seconds. This alarm is ignored during the first 8 seconds after starting the engine. | Check for the belt, the charger, or the alternator. |
| [°C] | Engine High-Temperature alarm. The Be172 triggers this alarm and shuts down the engine if the switch input [°C] is closed for at least one second. This alarm is ignored during the first 8 seconds after starting the engine. | Check the engine cooling system. |
| [ALAr] | Emergency alarm. The Be172 triggers this alarm and shuts down the engine if the switch input [ALR] is closed for at least one second. | Check the emergency button status. |
| [FuEL] | Fuel level alarm. The Be172 triggers this alarm if the switch input [FUEL] is closed for at least one second. Based on the settings of the parameter [P3], the BE172 triggers a warning (it features auto-reset) or shuts down the engine after a programmable time. | Refuel the tank |
| [ALr1] | Alarm 1. The Be172 triggers this alarm if the switch input [SPARE] is closed for at least one second. Based on the settings of the parameter [P4], the Be172 triggers a warning (it features auto-reset) or shuts down the engine after a programmable time. | Check the Alarm 1 source. |
| [oiLP] | Low oil pressure. The Be172 triggers this alarm and shuts down the engine if the oil pressure switch connected to the [OIL] input is closed for at least one second. This alarm is ignored during the first 8 seconds after starting the engine. | Check the oil level. |
| [FAIL] | "Fail to Start" alarm. The Be172 triggers this alarm and shuts down the [FUEL] output if it does not detect, within 20 seconds, a valid source of engine running from terminal [D+/WL] or the open contact of the oil pressure switch. | You have forgotten the KEY in the ON position. |
| [bXX.X] | This blinking message indicates a low/high battery voltage 11.8/15,6V or 23.6/31.0V | Check the battery |
| [Err-] | The Be172 fails to enter the ‘PROGRAM MODE’ due to an erroneous input setup. | |
| [Err2][Err1] | The supply is lower than 10V. The Be172 denies access to the memory.
Check the DC supply. |
|
| [EE.Er] | The Be172 failed the memory initialisation routine during power-on. Remove the supply for a few seconds. If the error persists, replace the Be172. | |
3.0 FUEL SOLENOID & STOP SOLENOID
To stop the engine, we recommend that you use a FUEL SOLENOID (energised to run). This solenoid must be connected to the output [FUEL] via a pilot relay. In the case of STOP SOLENOID (energised to stop), you are required to set up the adjustable parameter [P2] as indicated in the programming instructions. You are required to connect the STOP SOLENOID to output [ALARM] via a pilot relay as indicated in the wiring diagram. The Be172 will energise the output for the programmed STOP time. When you use the output [ALARM] to drive a STOP SOLENOID, the ALARM function output will no longer be available. In other words, the STOP SOLENOID output shares the same output as the ALARM. The factory setting for the [ALARM] output is to ALARM MODE
4.0 KEY START PROGRAMMING INSTRUCTIONS
There are four adjustable parameters: [P1], [P2], [P3], and [P4]. Follow the instructions.
1) Make sure the battery supply is over 12Vdc, but wait to connect it.
2) Turn the key to OFF and connect the terminal [PRG] to the battery minus.
3) Connect to the battery minus the “[TERMINAL]” associated with the parameter you want to program. The following table shows the allowed combinations. A disallowed connection triggers an error code.
| DISPLAY | TERMINAL | DESCRIPTION | DEFAULT | OPTIONS |
| [P1] | [°C] | Pre-glow settings | OFF=No preglow | 6” 15” 30” 45” 1’ |
| [P2] | [ALR] | Alarm/Stop solenoid | OFF=Alarm mode | 5” 15” 30” 45” 1’ 2’ |
| [P3] | [FUEL] | Fuel alarm modes | OFF=Warning only | 5’ 10’ 20’ 30’ 60’ |
| [P4] | [SPARE] | Alarm 1 modes | OFF=Warning only | 5” 15” 30” 45” 1’ 5’ |
| [Err-] | The Be172 detected an invalid combination of inputs. For example [PRG] + [OIL] or [PRG] + [°C] | |||
4) Connect the supply. The display will indicate the message [Prog], and for a second, the name of the parameter ([P1] for example). Finally, the display indicates the active setting (usually the factory default).
5) Turn the key ON. The Be172 will automatically scan, in sequence, each option for two seconds (if you have selected [P1], the Be172 displays OFF-6”-15”-30”-45”-1’).
6) When you see on display the proper option, turn the key to OFF: the display will blink twice and stores the new setting.
7) Remove the supply, remove the [PRG] connection, and remove the “[TERMINAL]”.
8) Apply the supply after the display check. the Be172 displays the parameter you modified ([P1] for example) and the setting ([6”] for example). All the time you supply the controller, you will be aware of the status of the parameters.
5.0 KEY START RECOMMENDED WIRING DIAGRAM
Relays and solenoids connected to Be172 must be wired to flywheel diodes. If the charger alternator is not available, connect the D+/WL to OIL PRESSURE to simulate it. The terminals #15 / #30-1 are internally connected to a normally closed contact for the Be172 standard version. The normally open contact option (closed in ON position) is available only on request, part number Be172B. In this case, the contact closes when you turn the key on. In case you need to supply a dashboard, the Outputs 15/54 features a blade terminal capable of supplying 5 amps.