wiring for mutliple rtu shutdown for smoke det.

[dmd-marc]

I have 4 rtu with system sensor duct smokes (m/n dh100acdc) that are required by the mechanical inspector to all shutdown at the same time when one of them trips. This system is hooked up to a central alarm system for the strip center. The alarm guy has his points landed and all I need to do is wire the multiple shutdown. I already am using one set of normally closed contacts for the fan shutdown on each indiviual rtu. Does anyone have any suggestions on how to wire these duct detectors so when one trips they all trip? Any help would be appreciated. Thanks

[markwolf]

Am I understanding you are shutting the fans off with the smoke detector already?
I would change out the relays to dpdt relay in a box & be done with it if so.

[dmd-marc]

The rtu's currently are each wired up individually to the normally closed set of aux contacts on their respective duct detector. When the duct smoke trips, the fan shuts down. Each duct detector has 2 sets of spdt dry contacts. I need to wire them up so that when one the detectors trip, all 4 rtu's shutdown.

[markwolf]

run the dry contacts in series any one opens the coil circuit for the relay.
breaking g might not shut the unit down on a call for heat.You might need to break r.

[graybones]

One relay with 4 nc contacts or two relays with 2 nc contacts and a seperate transformer. Wire the the new relay(s) coil to the low voltage side of the new transformer, running one leg in series through the nc contacts of you smoke dectectors before landing it on the relay(s). Wire either R or G from each unit through a relay contact.

[mrhvacmechanic]

If your detectors are wired to the central system, let the fire guy give you the four pole relay.
Run your four unit control circuits individually through the contacts on his relay. Let his system power the coil of the relay to drop out the four units.

Even though you ran the control circuit of each rtu through its own detector contact, you can run the same wire through the contacts on the relay. putting the relay and the detector contacts in series.

The additional second contact on your detector should be wired to trip the building system, thus his relay provided will stop all 4 units.

[superfittertech]

I have 4 rtu with system sensor duct smokes (m/n dh100acdc) that are required by the mechanical inspector to all shutdown at the same time when one of them trips. This system is hooked up to a central alarm system for the strip center. The alarm guy has his points landed and all I need to do is wire the multiple shutdown. I already am using one set of normally closed contacts for the fan shutdown on each indiviual rtu. Does anyone have any suggestions on how to wire these duct detectors so when one trips they all trip? Any help would be appreciated. Thanks

try this link see page 6 for multiple fan shutdown.

http://www.systemsensor.com/pdf/I56-0084.pdf