The Simplex 4098-9714 TrueAlarm photoelectric sensor mounts on the 4098-9792, 4098-9789, 4098-9791 and 4098-9780 bases, plus the sounder, isolator and CO bases listed below. The 4098-9747 CO cartridge is due when the panel reports the CO sensor expired: 10 years on 4007ES, 4010ES and 4100ES, 5 years on 4100U.
Which bases take the 4098-9714 photo sensor and the 4098-9733 heat sensor?
Both sensors use the same TrueAlarm bases. The base, not the head, decides what the device can do (relay, remote LED, sounder, isolator, CO) and which Simplex communication channel it can sit on.
| Base | What it adds | Communications | Sensors listed by Simplex |
|---|---|---|---|
| 4098-9792 (white), 4098-9776 (black) | Standard base, no options | IDNet or MAPNET II | 4098-9714, 4098-9733 |
| 4098-9789 (white), 4098-9775 (black) | Wired connections for a 2098-9808 remote LED or a 4098-9822 unsupervised relay | IDNet or MAPNET II | 4098-9714, 4098-9733 |
| 4098-9791 | Four-wire base for the 2098-9737 supervised relay; needs separate 24 VDC | IDNet or MAPNET II; not for the 2120 CDT | 4098-9714, 4098-9733 |
| 4098-9780 | Two-wire base for the 4098-9860 supervised relay; no separate power | IDNet or MAPNET II; not for the 2120 CDT | 4098-9714, 4098-9733 |
| 4098-9793 | IDNet isolator base | IDNet only | 4098-9714, 4098-9733 |
| 4098-9794 | Piezo sounder, powered from 24 VDC or a compatible NAC | IDNet or MAPNET II | 4098-9714, 4098-9733 |
| 4098-9772 | 520 Hz low-frequency sounder | IDNet only; software-revision dependent | 4098-9714, 4098-9754, 4098-9733 |
| 4098-9770, 4098-9771 (with sounder) | Carbon monoxide sensing module in the base | IDNet only: 4007ES, 4010ES and 4100ES at software revision 2.01.02 or higher; 4100U at 12.05 or higher | 4098-9714, 4098-9764, 4098-9733 |
The standard-base data sheet also lists the 4098-9832 adapter plate, required for surface or semi-flush mounting on a 4 inch square box and for surface mounting on a 4 inch octagonal box. For a 4098-9714 on a new standard base, the usual pair is the 4098-9714 head and the 4098-9792 base. The heat version is the 4098-9733.
Where is the address set: in the sensor or in the base?
In the base. Simplex puts the addressable electronics and the address DIP switch in the base, under the removable sensor and reachable from the front. Each base uses one address, and the address stays with the location when a head is removed for service.
That is why a head swap is quick, and why Simplex allows a heat sensor to stand in for a smoke sensor during dusty construction without reprogramming: the panel flags an incorrect sensor type and the heat sensor runs at a default sensitivity.
What is the 4098-9747 CO replacement cartridge, and when is it due?
The 4098-9747, called the CORC, is the replaceable carbon monoxide sensing element for the 4098-9770 and 4098-9771 CO sensor bases. You replace the cartridge, not the base.
It is due on the panel's schedule, not on a guess:
- Simplex gives the CO element a set operational life of 10 years on 4007ES, 4010ES and 4100ES control units and 5 years on 4100U control units, tracked by a date code built into the CO sensor module.
- The control unit reports an "Almost Expired" trouble at 12 months and again at 6 months before end of life, then an "Expired (End of Life)" trouble.
- Simplex states that the sensor continues to function after the Expired trouble but that replacement is required to ensure proper detection accuracy.
- The TrueAlarm CO service report lists each CO sensor's current ppm reading, end-of-life date and state. Run it to see which cartridges to order.
The reason for the fixed life is in the same data sheet: unlike a photoelectric sensor, CO sensor technology does not support automatic sensitivity testing and drift compensation.
To reach the cartridge you remove the sensor head. The head is tamper-monitored, so removal causes a trouble at the panel. Simplex covers the job in the CORC Replacement Instructions, document 579-791, and the base in installation instructions 574-707. The 4098-9773 CO base with 520 Hz sounder has its own data sheet, S4098-0053, which we did not use for this guide; check it before ordering a cartridge for that base.
What replaces the conventional 4098-9601 detector, and which base does it need?
The current Simplex conventional photoelectric detector is the 4098-5601, listed to UL 268 7th edition. We list it as the replacement for the 4098-9601 on that basis; we did not find a Johnson Controls document that states the cross-reference in words.
The bases are different, and this is the part that catches people:
| Detector | Type | Bases listed by Simplex |
|---|---|---|
| 4098-9601 | Conventional photoelectric | 4098-9788 (the Foundation Series chart also shows the 4098-9683) |
| 4098-5601 | Conventional photoelectric, UL 268 7th edition | 4098-5207, 4098-5261, 4098-5680, 4098-5682 |
| 4098-5610 / 4098-5611 | Conventional heat, 135°F with rate-of-rise / 135°F fixed | 4098-5207, 4098-5261, 4098-5680, 4098-5682 |
Simplex does not list the 4098-9788 or 4098-9683 base for the 4098-5601, so plan on a new base with the new head. The 4098-5261 is the 4 inch two-wire base and the 4098-5207 the 5 inch two-wire base. The 4098-5682 is the four-wire relay base and needs a 24 VDC end-of-line relay on the circuit. The 4098-5680 two-wire relay base must be the only device on its circuit. Check the two-wire detector compatibility chart for your control unit before mixing old and new detectors on one zone.
Are TrueAlarm sensors usable on non-Simplex panels?
Treat them as Simplex-only. TrueAlarm sensors report through their base over IDNet or MAPNET II, and the data sheet lists Simplex control units only: 4007ES, 4010, 4010ES, 4100ES and 4100U, the 4008 with a reduced feature set, and 4020, 4100 and 4120 series equipment fitted for MAPNET II. No Simplex document we read lists another manufacturer's panel.
What to order
Sensors, bases and the CO cartridge are in the Simplex collection; bases from every brand are in the bases and sounder bases collections. For a service list covering several buildings, request a quote. In-stock orders placed by 3 PM ET ship the same business day.
Compatibility must be confirmed against the control panel's listing documents, and the installation must follow NFPA 72 and the local AHJ.
Sources
- Simplex data sheet S4098-0019 Rev. 31 (06/2023), TrueAlarm Analog Sensors, Photoelectric and Heat; Standard Bases and Accessories: docs.johnsoncontrols.com
- Simplex data sheet S4090-0011 Rev. 26 (06/2023), IDNet and MAPNET II Addressable Devices, Device Communications Compatibility Chart: docs.johnsoncontrols.com
- Simplex data sheet S4098-0052 Rev. 6 (05/2025), TrueAlarm CO Sensor Bases for Smoke, Heat, and Photo/Heat Sensors using IDNet Communications: docs.johnsoncontrols.com
- Simplex data sheet S4098-0028 Rev. 12 (06/2023), Sounder Base 4098-9794: docs.johnsoncontrols.com
- Simplex data sheet S4098-0054 Rev. 8 (02/2024), TrueAlarm 4098-9772 Sensor Base with 520 Hz Sounder: docs.johnsoncontrols.com
- Simplex data sheet S4098-0025, TrueAlarm Analog Sensors Model 4098-9793 IDNet Isolator Base: docs.johnsoncontrols.com
- Simplex data sheet S4098-0059 Rev. 2 (10/2024), Photo-Heat, Photo, and Heat Detectors for Two-Wire and Four-Wire Bases: docs.johnsoncontrols.com
- Simplex, 2004 and 2008 Foundation Series Fire Alarm Control Unit Two Wire Detector Compatibility Chart, Rev. B: docs.johnsoncontrols.com