Ansul system

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liquidtite

Senior Member
Location
Ny
Doing an ansul system was looked up some diff installs online .
one way showed that you can Have the exhaust not have the option of being switched off
when in alarm mode by bringing steady hot to the n/o on the mocroswitch and then it will

keep the exhaust on even if someone turns of switch .

is this code or just a common practice .

the way o have it wired now is the switch turns on makeup air and exhuast at the same time

the switch leg Turns on exhaust coil and is spliced in Parrel to the common on the micro and

n/c bring power back to the makeup air coil to turn on make up air .

so if alarm goes on ,makeup air shuts off and exhaust stays on Bc it’s not wired I series with
micro switch . But it still give option to turn off exhaust in alarm mode.

should i I bring the steady hot feed to the n/0 so if someone turns off switch
exhaust will still stay on.
 

rambojoe

Senior Member
Location
phoenix az
Occupation
Wireman
there is a very very good thread about ansul systems from around 2016. ill try to paste it here for you.

edit- oh... it was a post you started! oops.. I couldn't paste it, sorry
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Doing an ansul system was looked up some diff installs online .
one way showed that you can Have the exhaust not have the option of being switched off
when in alarm mode by bringing steady hot to the n/o on the mocroswitch and then it will

keep the exhaust on even if someone turns of switch .

is this code or just a common practice .

the way o have it wired now is the switch turns on makeup air and exhuast at the same time

the switch leg Turns on exhaust coil and is spliced in Parrel to the common on the micro and

n/c bring power back to the makeup air coil to turn on make up air .

so if alarm goes on ,makeup air shuts off and exhaust stays on Bc it’s not wired I series with
micro switch . But it still give option to turn off exhaust in alarm mode.

should i I bring the steady hot feed to the n/0 so if someone turns off switch
exhaust will still stay on.

I wire them that way because it's required that the make up air go off during an alarm/fire but the exhaust must stay on.
 

luckylerado

Senior Member
Exhaust is not required to be shut down on alarm but I do not read the code to say it is required to stay on either. Certainly makeup air is to go down and the gas is supposed to be wired to the controller to shut off as well as shunting power under the hood but whether the exhaust shuts down, stays on or comes on in my experience is an AHJ call.

NFPA 17 for dry and 17A for wet systems is where I recommend looking for code language.
 

liquidtite

Senior Member
Location
Ny
Ok thanks for reply’s so what I gathered from
the post were that it’s not a code thing to have the exhaust wired

so it cannot be turned off in alarm mode just a good idea .

Anouther question I have . How many amps are the micro switches
usually rated for , and how many usually come with a single basic system .


also what need to happen when system goes into alarm mode as far as the fire alarm
aspect is concerned .
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Ok thanks for reply’s so what I gathered from
the post were that it’s not a code thing to have the exhaust wired

so it cannot be turned off in alarm mode just a good idea .

Anouther question I have . How many amps are the micro switches
usually rated for , and how many usually come with a single basic system .


also what need to happen when system goes into alarm mode as far as the fire alarm
aspect is concerned .

Before you dismiss that the exhaust must remain on you should contact the AHJ (or Fire Marshal in my case) to see what's required in your area. They can also tell you what else needs to happen such as what all needs to be turned off, including gas.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Oh Larry where are you?

Calling Mr Fine!
You rang?


I have wired many hood systems, both new and upgrade. When system trips:

The exhaust fan must turn on (in night mode) or stay on.

The make-up air must turn off or stay off (in night mode).

Any electrical appliance or outlet under the hood must lose power.

Gas valve must turn off when system trips. Must be manually reset.

If gas w/solenoid valve w/reset box, exhaust must be on for gas to flow.

If gas w/mechanical valve, must have T-stat in hood activate exhaust.

Horn/strobe or connection to building fire alarm system must activate.


I drew this a long time ago:


primary-wiring-diagram-for-ansul-system-6115.jpg

 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Anouther question I have . How many amps are the micro switches
usually rated for , and how many usually come with a single basic system
21 amps is what I have seen, and they're only switched under load during testing and actual fire situations.

also what need to happen when system goes into alarm mode as far as the fire alarm
aspect is concerned .
See my previous post.
 
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