fire suppression/hood control

[jemsvcs]

Looking at a job which includes some type of control relay setup for the exhaust and inline fans and hood lighting if a fire suppression system goes off. Very limited information is available at this time. Has anyone installed this type of system before? Any schematics available or links to some solid information on these types of systems?

Thanks,

Jemsvcs

 

[luke warmwater]

Re: fire suppression/hood control

Installed enough.
Do you know which manufacturer it is??
Not only the intake, and lighting has to be halted, but any outlet under the hood, ie. receptacle for gas cooktop, or electric griddle.
Some systems are completely wired with the contactors and are labled extremely well, others have about a gazillion (technical term) wires that you have to have to figure out.
Some systems have a seperate contact for you to hook-up to remote-locate your own contactor for these extra items.
Any of the manufacturer reps should be able to walk you through their system or fax you a copy of the lay-out.

 

[jemsvcs]

Re: fire suppression/hood control

the fire supp. system is an Ansul...not sure as to the model#...it is a dry type.

 

[luke warmwater]

Re: fire suppression/hood control

The last Ansul system that I did was 120v/1ph., with/ 1 exhaust fan, 1 Supply fan, 3 lights.

Control input 120v.: H1, N1
Lighting input 120v.: H2, N2
EXH-1 input 1ph/115v: L1, FN1
SUP-2 input 1ph/115v: L2, FN2

2 spare relay contacts: R2-1, R2-2

1 relay for connecting signal to Fire Panel: MS-2

Your system could be totally different!
Ansul Tech support should be listed on the unit, I don't have the number here.
You could also do a search on Google, etc...

 

[luke warmwater]

Re: fire suppression/hood control

Also,
Contactor: C1 was for the EXH fan
Contactor: C2 was for the SUP fan

If the one that you are doing is new, then I would imagine it to be very well labled. You should basically just have to enter your wires into the control cabinet and make your terminations. All of the control wiring should be factory installed.
But, then again, you never know.

 

[bigjohn67]

Re: fire suppression/hood control

Manuf. do not always include the control box. In this case we:
Bring contol circuit to line side of switch on hood.
Pigtail on the load side of the same switch 1 wire going to the micro switch and the other to the exaust contactor.
On the return from the micro switch, we feed the contactors that feed the supply fan, lights and other circuits that may be under the hood.
This provided 1 switch operation for the hood (exhuast,supply, lights, etc.)
When the ansul is "fired", it kills control power to the supply fan and lights contactor, while the exhaust remains running.

Switch on hood must be on for anything under the hood to work. This also keeps anyone from doing any cooking without the hood "on" since it kills all power under the hood, including outlets.

 

[luke warmwater]

Re: fire suppression/hood control

Big John, just for clarification:

Originally posted by bigjohn67:
Manuf. do not always include the control box. In this case we:
Bring contol circuit to line side of switch on hood.

Pigtail on the load side of the same switch 1 wire going to the micro switch and the other to the exaust contactor COIL.

On the return from the micro switch, we feed the contactor COILS that feed the supply fan, lights and other circuits that may be under the hood.

This provided 1 switch operation for the hood (exhuast,supply, lights, etc.)

When the ansul is "fired", it kills control power to the supply fan and lights contactor, while the exhaust remains running.

Switch on hood must be on for anything under the hood to work. This also keeps anyone from doing any cooking without the hood "on" since it kills all power under the hood, including outlets.

I just wanted to clarify that you fed the coils not the line side of the contactors for the sake of not knowing if jemsvcs understood you properly.

Are you saying that you've had to do this to an actual ANSUL fire suppression system? We've had to wire other brands from scratch like this, but never ANSUL.

 

[jerryb]

Re: fire suppression/hood control

If you had 10 jobs all with an exhaust hood there would probably be 10 different ways to wire them. Of the hoods that we see the typical installation would be to wire the system so that if there a fire under the hood, then the "supply" fan shuts down, all the electrical cooking equipment under the hood shuts-off and the gas valve is closed (normally spring loaded). The "exhaust" fan would remain running so as to pull the smoke out of the space and also pull some of the Ansul powder up into the hood to smoother any flames inside the exhaust duct. We typically don't shut the lights off, they are not a part of the equipment and I would rather not put the cook into sudden darkness because of a fire. Hope this helps.

 

[fishin' electrician]

Re: fire suppression/hood control

I agree with jerry about the 10 jobs/ 10 different ways to wire. I have experienced this within the same restaurant chains. Until you have all the specs, you really won't know what you're up against.

I've worked a few different types of setups. The simplest of which had the Ansul switch take out a shunt trip feeder breaker that fed a panel dedicated to all hood/under hood loads except the exhaust. Others used many shunt trip branch breakers, but most are more as the others have described above.

 

[scott moran]

Re: fire suppression/hood control

In the event that there is not enough room in the contactor for the outlets for the cooking appliances I have used the micro switch to trip a shunt trip breaker to kill these circuits.

 

[roger]

Re: fire suppression/hood control

Many of these package systems have their control schematics online now.

I have only wired one of these package systems, the rest have been as the others have stated, one side of the micro switch signals the F/A system the other side can operate the shunt trip or an ice cube relay to perform the required functions i.e. exhaust start, supply shutdown, equipment shutdown, gas solenoid shut off etc...

Roger

 

[ccha9219]

Re: fire suppression/hood control

I agree with roger
you can accomplish the required affect with two ice cube relays and a set of N/O N/C contacts
Run your control ckt thru the switch(s) on the hood for normal operation
also run your control ckt thru your N/O contacts on the ansul microswitch to the relay that has your exhaust fan on it(This is why you need two relays)
On ansul dump the N/O will energize and keep your ex fans running.
You will also need to use your control ckt to shunt all power under the hood ( Put your switch leg for your shut trip on the N/O contact also)
ccha9219