Troubleshooting a SIM or SIM+ module
|IBC Part #||Description||Boiler Model|
|P-271||SIM+ (Safety Ignition Module) replacement kit||
SL 10-85 G3, SL 14-115 G3, SL 20-160 G3, SL 30-199 G3
|P-270||SIM (Safety Ignition Module plus) replacement kit||
SL 26-260 G3, SL 40-399 G3
Software release # ..................................... (e.g., )
- All G3 modules have 1.03.xx software.
- 1.03.xx.xx software is backwards compatible for G1 and G2 boilers using V-10 touchscreen controllers. Updating these boilers with the latest software will provide features afforded to G3 boilers such as basic load combining, zoning through Express Setup, maintaining a system tank temperature by sensor (without need of a thermostat) as well as a straight line curve, new time clock, burner time offset and more.
The SIM consists of a processor called the Safety Ignition Processor (SIP). SIP's function ensures that the boiler fires according to safety protocols.
The added benefit of a SIM+ module is that it controls the fan directly. This is because it contains a second processor we call the Fan Control Processor (FCP). Note that the SIM and SIM+ modules are not interchangeable.
Record the current SIP and FCP revisions. The original revision software began with 1.00.
SIP revision..................................... (e.g., 1.xx)
FCP revision ................................... (e.g., 1.xx)
The SIM module has a SIP revision only . The SIM+ has a SIP and FCP software revision.
It's a good idea to cross-check this information with the information provided on the label. Note that not all boards were labeled with this information.
|Mode ..................||SIPVersion ..................||SIP Status ...................||FCP Status ..................|
There are up to three LED indicators on the modules. For information on the LED operating status,
|LED1 ......................||LED2 ......................||LED3 (SIM+) ......................|
Flame Outs count ..................................
The SIM/SIM+ records every instance of the flame dropping below 1µA after establishing a flame. Often this indicates improper combustion on low fire, vent termination issues, or low inlet gas pressure. Make adjustments as required.
Note the current Flame Out value, and leave it with the boiler as a baseline for your next visit.
Alarm alert text .....................................
Flame Sig/Vent BLK error
Flame Sig/Vent BLK indicates a low flame signal. The minimum value for the majority of boilers is close to 498/249=2 μA for 6 seconds.
See the table below for flame minimum signal values:
|Flame Minimum Signal|
|Model||Minimum Raw Value||Anticipated Raw Value||µA Min.||Anticipated Value µA|
|SL40-399 G3||871||1, 195||3.5||>4.8|
For normal operation, the signal must be greater than the assigned minimum value. If the signal drops below the assigned minimum value for less than 6 seconds, the unit will continue to operate with no alarm. It must always remain greater than 1 µA. Software 1.03.7 runs a new routine that increases the heating capacity to 20% of the maximum firing rate of the boiler (e.g., for the 115, 23MBtuh) to protect against windy conditions as a first step in preventing nuisance flame signal errors for all SL Series boilers less than 199,000BTUs. This applies only to the units using the SIM+ models - SL models after 1.10.1.
Flame Out is a value recorded at the bottom of the SIM Status menu. It occurs when the flame signal lowers below 1 µA. This value will not provide an error. It is a cumulative value, and currently, is not resettable.
Trials for Ignition Exceeded (units using SIM+ only)
- Check the:
- Incoming gas for a sufficient supply.
- Basic safety operation of the boiler as it is initiating a call for heat.
- Unplug the connector from P5 location on the SIM+ module and measure the Ohm’s resistance across the removed connector.
- The value should be between 60 and 70 Ohms.
- Remove the “P5” Molex connector from the SIM+ and touch the meter leads to the pins.
- Once verified, reinstall the P5 Molex connector.
- Confirm the correct voltage 24Vdc (must be >22Vdc).
- To check the voltage the boiler must run through a "Trial for Ignition".
- Now test by back-probing the P5 Molex connector when it is in place and by verifying that the coil of the gas valve is within the correct range.
- If NO voltage is present, replace the SIM+ module
(see Service Parts); for example, if you see a voltage and it is low, approximately 1 to 5Vdc.
Following is a description of the information in the SIM/SIM+ status table. For the alert text in Bold, first attempt a reset; the boiler may function, but plan on a replacement of the SIM/SIM+.
|Burner On Call||Burner On Call: Fire may not be present. The SIM/SIM+ has determined it is safe to power the burner.|
|Gas Valve Open||□||Gas Valve Open: Self-explanatory.|
|Flame Detected||□||Flame Detected: Self-explanatory.|
|FLame Current||0.00||Flame Current: uA in real time.|
|Max. Trials||□||Max. Trials: No flame detected after 3 ignition trials.|
|Low Water||□||Low Water: LWCO detected air in the system.|
|Outlet Over T||□||Outlet Over Temperature — Temperature is >98⁰C (208⁰F) or >94⁰C (201⁰F) +1⁰C (1.8⁰F)/ Sec. or 94⁰C+5⁰C (9⁰F) for a second.|
|Outlet Sensor||□||Stack Over Temperature: 99⁰C (210⁰F) for PVC venting, 110⁰C (230⁰F) for CPVC and PP.|
|Stack Over T||□||Stack over Temperature: 99⁰C (210⁰F) for PVC venting, 110⁰C.|
|Stack Sensor||□||Stack Sensor: Verification of a failed sensor.|
|Flame Outs||0||Flame Outs: Count of flame values below 1μA over the lifetime of the unit. Verify Venting conforms to the manual, check inlet gas pressure during operation, check combustion, look for vent restrictions.|
|No 170V||No 170V: Supplied from the 24Vac, converted to DC before the 170V s|
|No 3.3V||□||No 3.3V: Drives the internal processor.|
|Gas V Voltage||□||Gas V Voltage: 24VAC units only (260G3, 399G3, all G1 and G2 models). Monitors the internal series switching.|
|Gas V Current||□||Gas V Current: Must have 24V present. It is looking for an open or a short.|
|ATD Fault||□||ADT: Analog to digital converter. Replace module.|
|No 60Hz Sync||□||No 60HZ Sync – 24Vac – Look for wiring connection issues or non-sinusoidal waveform. Power supply.|
|No FCP Comm.||□||No FCP Comm: Fan Control Processor is not communicating with the V10 control.|
|Fail Safe Mode||□||Fail Safe Mode: Software detected SIM/SIM+ issues.|
|Boiler Fault||□||Boiler Fault: SIP lockout [abandoned] - Update Software.|
|No Flame||□||No Flame: Accumulation of events check for other status marks.|
|No Ign Supply||□||No Ign Supply: Internal error, needed to measure flame current.|
|No Flame Drive||□||No Flame Drive: Internal error, needed to measure flame current.|
|Low Flow||□||Low Flow: Water system issue (i.e. excessive temperature rise).|
|No Spark||□||No Spark: Self-explanatory; a report of a measurement by the SIM/SIM+.|