HVAC question

[jumacao]

I am validating and HVAC system. System have two HVAC running in sequences. They need to have an interlock between the two HVAC smoke detector. That interlock can be logical ????

 

[blutfort]

By logical do you mean in software and communicated over a DDC communication link? e.g. Lon, BACNet, N2, etc...

I can only speak for US regulations, and then your local jurisdiction may have some specifics that need to be considered.

If you do mean over a communications link the controllers should be listed to the UL smoke control code (UL 864 I think. Possibly NFPA 92A).

I would typically avoid adjustable/configurable software for any life safety application. But I have seen it used at times.
Personally, I would hard wire each of the local machines to meet the minimum requirements, and then use the com-link to "enhance" the purge/pressurize system.

 

[DRWeig]

Do what blutfort says.

Even if communication link and controller are UL listed for smoke control, failure of either will allow the fans to keep pumping when smoke detector is calling for stop. Not worth the risk!

Goober Dave