Restaurant hood heat detector

[GoldDigger]

If it turns on the hood it must also turn in makeup air, yes.

 

[kwired]

The sensor may not be required to turn on makeup air directly.

It is more likely the make up air is required to somehow be interlocked so that it is on anytime the hood is on.

 

[gadfly56]

One more question,
Should it also turn on make up air as well as the exhaust?, (So not to create a negative pressure in building. The make up air is directed thru duct to the rear of appliances.) and would be energized during normal operation of a wall switch to turn on/off hood ventilation.

The ansul system will shut down make up air, trip shunt breakers, activate horn/strobe and close (cable actuated) gas valve. Sound good?

Sounds good. As kwired mentions, the make up air should probably be interlocked to the exhaust fan(s), but I'm not sure what the code requirements on this are. It's at least good practice. Just make sure that the make up air shutdown from the Ansul system is on the load side of the interlock if it's not part of the shunt trip breakers.

 

[iwire]

Yes, that's the intent of the code section. Appliances on, exhaust on.

We seem to go at it in another direction.

Exhaust fan off, appliances off.

Air flow proving switch in the exhaust duct that controls the gas valve. No airflow = no gas.

 

[gadfly56]

We seem to go at it in another direction.

Exhaust fan off, appliances off.

Air flow proving switch in the exhaust duct that controls the gas valve. No airflow = no gas.

That could work too. It depends on how many call backs you want to troubleshoot the vane switch in the duct. Or for replacing it when the hood cleaning contractor destroys it.