AV Replacement on Simplex 4007

I have a Simplex 4007 with TrueAlert AVs on the nac. Both of the strobes were bad. I replaced them with System Sensor P2LR AVs. Now I’m having an issue with getting a T3 tone and a synced strobe. I know it’s the programming in the 4007 for the TrueAlert. Looking for an idea someone would have, short of having Simplex come out and reprogram. That is not a option. My Director burnt that bridge. Any thoughts would be appreciated.


Do you know what the NAC is programmed to do? It’s quite probable it is configured for SmartSync but since this is a 4007 it may be an addressable NAC, on the TrueAlerts does it say ES? Youll likely have to replace the P2RLs with new TrueAlerts. Also I am assuming this is a real life safety system, so I would recommend talking to Simplex, or one of the techs on this forum.

FireAlarmTech9 is on the right track. The sync control signals are completely different for the Simplex devices and the System Sensor devices. It is not possible to mix 2-wire horn strobes of different brands on the same circuit. The devices in question will have to be replaced with Simplex devices of the same model as removed or a compatible upgraded model.

Theoretically, would adding a 4905-9815 sync module allow the System Sensor horn to function on the NAC?

I believe this will only work if the signals are SmartSync, not addressable.

There are no addressable anything on the system. It has a zone card. I will be removing the panel and installing a MS10UD. We have a stock of them and it will be more cost effective. Thanks for the input.

If they are the only devices on the NAC and in that field of view or building, theoretically you can install an MDL3 module to synchronize the System Sensor devices. Simplex panels, to my knowledge, can only be programmed to sync Simplex strobes. However, you may have issues with that since the Simplex panel is already outputting Simplex sync coded 24 volts. I don’t know if the MDL3 can properly handle that kind of input.

There is one thing you might want to take into account. Certain version of the MS-10UD output full-wave rectified current. From what I understand, FWR current will cause Simplex devices manufactured from the mid-1990s and later to operate erratically and even fail if used on a NAC that outputs FWR. Page 3 of this compatibility sheet indicates which models of the MS-10UD output filtered power and FWR.

Disclaimer: I am NOT a fire alarm technician. This information should be verified by a technician before you make any decisions. Thank you.

We really don’t know exactly what Simplex NAs the OP has, except that they are not addressable. They could be 4 wire with sync strobes and panel operated horns or they could be 2-wire SmartSync devices. everyone is assuming they are SmartSync because he replaced some with System Sensor P2LR (P2RL, typo?) AVs, which are 2-wire devices. He has 2 different brands of NA devices, which each have their own sync signal pattern, on the same circuit. I seriously doubt that adding an MDL to the circuit will help. That would have 2 different sync signals on the same circuit.

If the 4007 is replaced with an MS10UD the same problem still exists. NA devices of 2 different brands with 2 different sync signal needs on the same circuit. The compatibility document does not list any Simplex NA devices. So in addition to replacing the panel ALL of the existing Simplex Truealert devices should be replaced. This just compounds the problem.

Many Simplex panels can also be programed to sync Wheelock devices, but you cant run two sync protocols on a single NAC.

If these are SmartSync TrueAlerts replacing the 4007 with an MS10UD will make all of the Simplex devices stop functioning unless you install a Simplex sync module causing the same problem. Although this is less of a concern, iirc the MS10UD outputs FWR which over time can cause damage to the TrueAlerts, even if they are running through a SCM (sync module).

But to keep myself covered please keep in mind I am not a tech.

To clarify, my response only applies if the two System Sensor horn/strobes are the only devices installed on that circuit/in the building. You cannot mix different manufacturers’ horn/strobes and have them sync with each other. Even if they are, the Simplex sync from the panel may very likely cause issues for the MDL3 if you cannot turn that off.

I have replaced all the Simplex true Alert devices with System sensor. I had a bad av and a intermittent short in one of the devices. So a MS10 will be fine.

Since you are replacing the panel be sure to check that any 2-wire smoke detectors installed are compatible with a Firelite panel. If the detectors you have installed are not listed in the compatibility document linked below they will have to be replaced. Detectors that are not listed as compatible may not work correctly and can negate the UL listing of the system.