Restaurant Hood Systems

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jimmyglen

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St. Louis, Missouri
I was wondring - on restaurant hood systems does the E.C always wire the alarms, gas valves, return air etc etc controls?

I do mostly resi work and the last time I did a hood system was years ago.

There is no "one" diagram for this just a lot of parts and seperate wiring diagrams. It sure seems like a lot of time could be spent on wiring this.

How do you guys handle this?

thanks

jim
 
I do the hood system wiring, and yes, there are a lot of ways to handle it.

Ansul makes a pretty trick relay that keeps things from auto-resetting when the power comes back on if you want to use contactors. You can also shunt trip a whole panel for the under hood equipment. Don't forget, in a fire event, makeup air shuts off if not already off, exhaust kicks on if not already on, and all underhood electrical equipment shuts down. Gas valves could be electrical or mechanical. Seen them both ways.

Larry Fine had a pretty decent sketch he posted once upon a time for wiring up the cherry switch on the ANSUL cabinet itself for makeup and exhaust air contol.
 
I was responsible in the few restaurants I have done. It too me some head scratchin but it's not rocket science, just a basic understanding of the function.

When the system is activated the gas and make up air go off and the vent stays on.

I think the only added equipment is a contactor with some NO and NC contacts and a jbox.
 
220/221 said:
I think the only added equipment is a contactor with some NO and NC contacts and a jbox.
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Them's the olden days. :grin:

Now, you gotta kill everything electrical under the hood too. You can do that with more contactors too, if you want to. Lately, I've just beeing putting in a small panel for the under hood equpment and feeding the main lugs with a contactor. Bigger hoods, shunt trip a main breaker in that subpanel.

There's a million-and-one ways to do this sort of work, but the end result is all that matters.
 
What else is under there. Lights?

You have to kill the lights?

How will the smoke know how to get out?

Oh yeah....elec fryers....gotcha.
 
mdshunk said:
Them's the olden days. :grin:

Now, you gotta kill everything electrical under the hood too. You can do that with more contactors too, if you want to. Lately, I've just beeing putting in a small panel for the under hood equpment and feeding the main lugs with a contactor. Bigger hoods, shunt trip a main breaker in that subpanel.

There's a million-and-one ways to do this sort of work, but the end result is all that matters.
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mdshunk,
Things may have changed without my knowing, but, at one time in this area, the determination of disconnecting everything "under the hood" was relative as to wheather the system was "dry chemical" or "wet".
If the systme was dry, you did not need to disconnect power sources that went to non-heat producing equipment.
 
augie47 said:
If the systme was dry, you did not need to disconnect power sources that went to non-heat producing equipment.
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This assumes that 2 months (or 2 years) after your final that the 'chef' doesn't decide to re-arrange things like which recept. the refr and fryer are using.

If it's under the hood it better get tied into the system. No exceptions.
 
mdshunk said:
What do you use under a hood that doesn't produce heat??
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(note I'm speaking for our regional Fire Inspection folks)
such things as motors on convection ovens, ignitors, etc. In the past, if the system was "dry" and the electrical ddi not produce heat directly, they did not require disconnect.

BryanMD. We have not been required to address "what-if" situations.
 
jimmyglen said:
I was wondring - on restaurant hood systems does the E.C always wire the alarms, gas valves, return air etc etc controls?
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We do - don't forget the reset for the NG.

jimmyglen said:
There is no "one" diagram for this just a lot of parts and seperate wiring diagrams. It sure seems like a lot of time could be spent on wiring this.

How do you guys handle this?
Click to expand...

A notebook :)

Seriously.

Keep track of all your own drawings - IF sometime passes between, rough, trim, and inspections (and there are a few inspections) "forgetting" what you did is not an option....being able to flip 2-wires WHILE the inspector/s is there saves the trouble of calling for a re-inspection.... among other things.

Keep ALL the specs from ALL the appliances in one spot along with that notbook and a copy of the panel schedule (for that particular job).
 
augie47 said:
We have not been required to address "what-if" situations.
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Take a look in the thread about stapling NM in crawl spaces, then we'll talk about this ok? ;)

As an inspector you aren't required and as an EC we aren't required either but in the example of commercial kitchen fire system (which all seem to be designed on the fly) a bit of belt & suspenders is a GoodThing; especially so when advising someone who hasn't ever done one like the OP.
 
Jim, yes, I've done quitre a few, and yes, I can figure them all out now. There is no one diagram that suits all systems, but as Marc and others said, the goal is the same, but there are so may variables of existing as well as new systems, such as:

Is this a new or existing system?

Exhaust fan only, or intake and exhaust?

One switch for both, or separate?

Direct-control of fans or contactor(s)?

120v, 240v, 1-ph, 3-ph, etc.?

Motor currents within micro-switch ratings?

Single-, two-, or variable speed exhaust?

Does the locality require the lights to go off?

Will there be a strobe and/or siren?

Existing method of de-energizing equipment?

With the answers to these questions, I can design a circuit with minimal parts counts. I often can use a single microswitch instead of both. Let me know if I can help.
 
LarryFine said:
With the answers to these questions, I can design a circuit with minimal parts counts. I often can use a single microswitch instead of both. Let me know if I can help.
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Last kitchen I did ...I used 3 of the 4 ansul micro switches and a 12 pole lighting contactor ~ 3 pages of my own drawings and notes, and re-worked the panel schedule 2x. :grin:

Ya gotta love change orders.
 
Then sometimes you have to trigger the FA system too. Fun, fun.

Whatever you do, do the next guy a favor and leave a drawing in the contactor enclosure or someplace obvious where it won't get lost or destroyed.
 
mdshunk said:
Then sometimes you have to trigger the FA system too. Fun, fun.
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I had the ansul guys swap out the 2 micro switches for a 4 - just in case...wound up using one of those "extras" for the FA connection. :wink:
 
jimmyglen said:
I think we have it wired. It really did burn up the labor hours.
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Burn - kitchen ....LMAO :D


jimmyglen said:
What kind of number do you guys put in on the bid?
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Kind of hard for me to determine how many hours in the kitchen...from pipeing a new panel to lamping fixtures....quite a bit...and the change orders only help to distort the numbers.
 
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