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Ansul System wiring

47K views 43 replies 18 participants last post by  JustElectric 
#1 ·
My client has and old commercial kitchen exhaust hood.
A new ansul system has been installed.
The new system has two 12v micro swithces.
One switch is for the alarm and the other for the electrical shutoff.

My question is, can I replace all of the circuit breakers for all circuits related to the hood with 12v shunt trip breakers with the 12v shunts connected to the 12v micro switch or am I missing something?
Sounds pretty easy.

Thanks in advance.
 
#8 ·
I am told by the company who installed the ansul system that the micro switch sends out a 12v signal when activated. This 12v signal is to be connected to the disconnect means for all elec. related equip under hood.
I will have to ask them about the gas valve.
 
#14 ·
when i wired an ansul system the gas contractor gave me a gas valve reset control box. one of these http://www.heiserusa.com/Fire_System_Accessories/Reset_Relays/Reset_Relays/835

they are really easy to wire just use your brain to make it work. the way they wanted it to work was the intake fan would shut off, the gas valve would shut off and the exhaust would stay on or turn on if it was not already. i dont remember exactly how the fire alarm hooked up to it but it was really simple to wire. basic wiring. 2 contactors with 120v coils
 
#12 ·
It likely has a contactor, and the microswitch controls the coil.

There could be a fuse in the hood, that opens in case of fire, mechanically

operating the microswitch. There is usually a wiring diagram with the unit.

The range hood installer will tell you what is required. At least he should!

The gas valve has a solenoid. If you go to a Honeywell sight, you will

likely find a wiring diagram. It is a very common system. I am sorry I can

not explain it any better.
 
#15 ·
if i remember correctly we had another microswitch installed for the fire alarm. we mounted an addressable module on the outside of the control box and ran 4 wires to the micro switch. the 2 positives spliced together and the 2 negatives spliced and went to the terminals of the switch. it went back to the module. Class A FA wiring. no resistor needed. we used fire lite products
http://www.monstermarketplace.com/f...sable-control-module-supervised-style-z-y-nac
 
#17 ·
99,
I've wired quite a few systems like your doing. I have never seen an ansul system that actually puts out any voltage, usually it's a micro switch attached to a cam mechanism, which is turned when the release handle is pulled. Usually for the line voltage equiptment we install a low voltage relay outside of the ansul cabinet, and use that to inturn shut off either a contactor or shunt trip panel. The gas solenoid is usually tied in with the hood control box. The exhaust must be on for the gas to flow. The hood control box usually has 2 contactors within it fresh air supply and exhaust. Usually they have auxilary contacts within the enclusure for such applications as fan shutdown and gas shutdown, as it all works together. If the unit trips out some municipalities want exhaust to remain on, others want all power to be cut so find out ahead of time. In my expierience the gas solenoid has always been 120 volts powered on to operate. I've put this on the same circuit as the hood lights and control circuit. hope this helps, or confuses the heck outa you
 
#19 · (Edited)
I got it fellas.
Remove and install a shunt trip breaker for every electrical device under the hood.
Run a low voltage wire from the 12v micro switch in the ansul system to the 12v shunt trips.(Shunt trips come in several voltages)
Make sure that the make up air shuts off with the shunt trip(S) and the the exhaust stays on.
And... some fire marhalls will allow for the hood lights to stay on, but include them in the shunt trip application...
Make sure that there is either a mechanical or electronic shut off for the gas line.

I love my job!
 
#26 ·
99Kilowatt said:
the micro switches have a 12v secondary. No one has asked about the gas valve.
I've personally never wired an ansul system that used 12v controls, but the micro switches are exactly that, a switch, I've never seen or heard of one with a "12v secondary" obviously there is 120v to the box, hits a transformer, that is if your not using the fire alarm power to trip the shunts. Shunting any equipment under the hood. I have also noticed it depends on the fire marshal inspecting it weather or not it starts or kills power to the hood, has something to do with the make up air, but I have had to wire them diff, in the same building because of diff inspectors. The 12v controls I would like to know more about in case I run into that.
 
#27 ·






Do I need a disconnect switch beneath this unit?

Can I have a separate switch to operate the lights inside the hood?

Am I asking too many questions?

I'm real nervous doing this job because I've never done one 'completely' before.

I have to leave to go look at some more work but I appreciate any help thanks.
 
#28 ·
We usually have to wire an electrical gas valve to close when the exhaust fan is turned off. There is a mechanical valve to shut off gas when the ansul is pulled
 
#29 ·
Magnettica said:
Do I need a disconnect switch beneath this unit?

Can I have a separate switch to operate the lights inside the hood?

Am I asking too many questions?

I'm real nervous doing this job because I've never done one 'completely' before.

I have to leave to go look at some more work but I appreciate any help thanks.
Im having trouble following. A disconnect switch for what, and a separate switch to do what with the lights? You planning on using shunt trips or a contractor?
 
#31 ·
Are you sure it is a 12 volt self powered system of just a 12 volt rated micro switch ? Every ansul I've encountered has a 120 volt micro switch which I control a DPDT contactor with to throw off make up air and turn on exhaust. One on occasion the FM had me install a 24 v anunciator in the main restaurant area
 
#32 · (Edited)
Thats a Pyro-chem system.
The micros are just dry form c switches.
120v AC 2 Amp rated.

They provide NO power of any type.
They simply open or close on activation.

In picture 2- the top cable is for the pull,right is for the thermal links and the left goes to the gas valve.
The N2 cartridge is placed above the 1/4" line.
When the system activates it fires the cartridge and then that fires off the tank.

NFPA 17A has all the requirements.

Basically ALL fuel sources have to shut down-IE: gas valve,all electrical under the hood- hood to floor have to be de-energized, make up air must shut down and The AHJ may or may not want the exhaust to shut down.

Most times the exhaust stays on.
 
#33 ·
Thats a Pyro-chem system.
The micros are just dry form c switches.
120v AC 2 Amp rated.

They provide NO power of any type.
The simply open or close on activation.

In picture 2- the top cable is for the pull,right is for the thermal links and the left goes to the gas valve.
The N2 cartridge is placed above the 1/4" line.
When the system activates it fires the cartridge and then that fires off the tank.

NFPA 17A has all the requirements.

Basically ALL fuel sources have to shut down-IE: gas valve,all electrical under the hood- hood to floor have to be de-energized, make up air must shut down and The AHJ may or may not want the exhaust to shut down.

Most times the exhaust stays on.

I agree with you. I have yet to see a set of contacts that were not dry on these systems.
 
#36 · (Edited)
It's a bit more complicated, but not a lot.

When the cable is pulled and the micro switches are tripped:

Gas valve, electric fryers, and make up air must shut off.

Exhaust hood must turn (or remain) on.

Sometimes they want the lights off also. Not in my area.

Shunt trip breakers make sense in some situations. The 120V micro switches make sense on most things. The units I've installed had two or three (each) NO and NC contacts right at the ansul supply trigger.


Gah! That was for the OP








Mag.

Do I need a disconnect switch beneath this unit?
No


Can I have a separate switch to operate the lights inside the hood?
The lights generally have a separate switch for normal operation. They may or may not be required to be disconected when the system is activated.

That is the exact system I hooked a while back.

Tell us exactly what equipment is under the hood and if the lights are required to be shut off. The rest is cake.


Put a short piece of conduit/flex on the pigtails and terminate everything in a 4S box. Run some conduit/flex from the ex fan/mua switch (possibly the lights) and another to the gas valve (if applicable)

You have two (white) commons, two NO's and two NC's. The NO, NC thing confused me with the "held open/closed" thing. Determine if the system is cocked, and ring them out to be sure. Usually they don't activate them until all the testing has been done.


Run the exhaust fan switch leg (from the line side) thru a NO contact. In case of fire, you want to vent the building even if the switch is turned off.

Run the make up air switch leg (from load side) thru a NC contact. In case of a fire, the last thing you want is fresh air being pumped in.



I believe the gas valve will be a NC type so power it (to open it) via a NC contact. There is not much amperage so it can be powered off the ex fan/mua circuit.

If there are any shunt trip reakers involved, I believe they activate/tripped by the 120 power. If so, they will go on a NO contact.
 
#37 ·
It's a bit more complicated, but not a lot.

When the cable is pulled and the micro switches are tripped:

Gas valve, electric fryers, and make up air must shut off.

Exhaust hood must turn (or remain) on.

Sometimes they want the lights off also. Not in my area.

Shunt trip breakers make sense in some situations. The 120V micro switches make sense on most things. The units I've installed had two or three (each) NO and NC contacts right at the ansul supply trigger.


Gah! That was for the OP








Mag.



No




The lights generally have a separate switch for normal operation. They may or may not be required to be disconected when the system is activated.

That is the exact system I hooked a while back.

Tell us exactly what equipment is under the hood and if the lights are required to be shut off. The rest is cake.


Put a short piece of conduit/flex on the pigtails and terminate everything in a 4S box. Run some conduit/flex from the ex fan/mua switch (possibly the lights) and another to the gas valve (if applicable)

You have two (white) commons, two NO's and two NC's. The NO, NC thing confused me with the "held open/closed" thing. Determine if the system is cocked, and ring them out to be sure. Usually they don't activate them until all the testing has been done.


Run the exhaust fan switch leg (from the line side) thru a NO contact. In case of fire, you want to vent the building even if the switch is turned off.

Run the make up air switch leg (from load side) thru a NC contact. In case of a fire, the last thing you want is fresh air being pumped in.



I believe the gas valve will be a NC type so power it (to open it) via a NC contact. There is not much amperage so it can be powered off the ex fan/mua circuit.

If there are any shunt trip reakers involved, I believe they activate/tripped by the 120 power. If so, they will go on a NO contact.
Sheesh, that's like what I said but much easier to read. :thumbup:
 
#39 ·
NFPA 17A 4.4.3
(summary)
All sources of fuel and electric power that produce heat to all equipment shall be shut down.(lamps produce heat)

Exhaust fans and dampers shall not be required to shut down.As they have been tested under zero and high velocity situations.

the gas valve must shut down 1st- the reason the control head activates it.

shut off devices shall require manual resetting after activation. (resetting the control head covers this,as the micros will reset then too.)
 
#40 ·
Thank you all who have replied to this thread in attempt to help me out. I sincerely appreciate your gratitude and I know more now than I did even yesterday. Thank you!

However, my friend CaptKirk is coming to bail me out tomorrow afternoon and then I get to wire a service with him the week after next. It must be the power of ElectricianTalk that gets me through.

See you tomorrow Tony.

Thank you!
 
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