Commercial exhaust hoods and make up air.

[RM Electric]

Hey gents,

I have an exhaust hood and a make up air chiller. I was told that I have to hook these two together, so that when the exhaust fan is on, the make up air must be on and if the hood is off you can not turn on the make up air.
The hood is a 220v,20a circuit?
The make up air is 220v,20a circuit?

How do I wire these?, and with what type of contacts or relays?

Also, this all has to be connected to an ansul system, which has to shut off the make up air, and keep the exhaust fan still running.

If any one can help please send any diagrams to xxxxxxxxxxxxxxxx.

Thanks,
Robert

 

[celtic]

You are going to need some shunt trip breakers and a "lighting contactor".

By "lighting contactor", I mean a contactor with poles equal to the number of devices/appliances that need to shut down when the ansul system is activated....PLUS one.

The PLUS one is for the EF that needs to be ON when ansul is activated.
(NOT the complete plan here )

I'll post a ladder diagram when I reach that point in my fiasco.

 

[LarryFine]

RM, I'd rather post responses here anyway, as others can share in the Q and A's. I will splash up one pair of diagrams now, but I have a few questions:

1) Does each blower have a separate switch, or is there one switch for both?

2) Are there hood lights that need to be extinguished, or any fire-alarm needs?

3) Can you check the actual current demands of the two blower motors?

4) Are there any electrical appliances located within the hood's coverage area?

For single-pole switching, or for separate contactor coils, using one switch for both:


Added: Before:

Added:After:

Notes: Your colors may vary. This setup only uses one micro-switch section. I also have a diagram for separate switches also using only one section.

 

[barbeer]

2) Are there hood lights that need to be extinguished, or any fire-alarm needs?

Recently had a plan of a UL listed "Captive Aire" hood assembly (prefab) come thru and it did not show the lites under hood shutting down on ANSUL activation which is contrary to my experience. The Fire Dept made the call that situation was o.k., would like other opinions of the lights staying on:

___O.K.

___not O.K.:smile:

 

[celtic]

....would like other opinions of the lights staying on:

My print shows everything UNDER the hood goes OFF....I'll let you know how that works out come final inspection :roll:

 

[RM Electric]

Thank you gentlemen for all your help. I tried to reply to each of you personally but time is short when you have your own businessw.