Vapor Fire damper wiring

[Birdsell36]

Hi Everyone - I recently got my VF-100 from the March sale and am in the midst of my installation. The electrical connections were simple and the wiring diagram was very easy to follow. Iwas hoping someone would be willing to help me through my power damper question as I have don’t have much knowledge in this area.

Plan: The VF will be hooked in parallel with an oil fired furnace. I have two existing 10x20 supply trucks, one feeds floor 1 and the other feeds floor 2. My plan is to have three 12” round ducts coming off of the VF plenum, two going into the first floor supply and one into the second floor supply. In the first floor supply one will have a power close/spring open damper and the other will have no damper. In the second floor supply there will be a power open/spring closed damper. Since we spend most of our time on floor 1, the thought would be to have to have the two 12”s open to this floor during the day and flip a switch in the evening closing one damper and opening the other allowing 12” of supply to floor 1 and 12” supply to floor 2. This will also always allow for 200 sq inches in a power outage. Can someone let me know what I need to buy to accomplish this besides the dampers? Maybe even share some in detail wiring help? I would be open to it being controlled by a switch or thermostat.

Other questions:

• Is your fan relay/transformer on the VF warm to the touch? I can hold my hand on it but it’s fairly warm.
• I need to add a check/backdraft damper in the two 10x20 supply trunks. I am thinking about making something with a piano hinge, 28 gauge sheet metal (9.5”x19”), and a stop on the bottom to prevent back feeding the oil furnace . Have you heard of anything more sophisticated or will this work?

I would appreciate help on any part of this post! Thanks!!

 

[brenndatomu]

Congrats on a wise purchase.
Do you have (or can make) a drawing of your duct layout?
I would have to check my transformer again...it is probably at least somewhat warm, but since its summertime now the furnace is stone cold.
The gravity dampers should work fine for blocking the oil furnace.
What voltage are your dampers?

 

[Birdsell36]

Thanks! I don't have any dampers purchased yet since I am still planning but have heard that retrozone is a good place to shop... I'm also pretty unsure of what I need (besides dampers) and how to wire them at the moment. Here is a picture of the furnace area and duct layout.

 

[brenndatomu]

Looks like a good plan...as far as the dampers I'd probably just use standard ole 24VAC powered dampers...I REALLY like the Belimo motors that I have on my dampers...just as with the VF100, they are a premium product.
You can use the transformer of the VF to power the damper circuit(s)...the Belimo motors have very low draw, especially in the "hold" position. Retrozone has some wiring help on their website IIRC, but their examples may be a lil more involved than what you need to get into for this application.
The "switch" for the second floor damper could be a thermostat, or you could literally just use a switch of some type too.

 

[Birdsell36]

Thanks. Excuse my electrical ignorance but your saying the VF transformer should be able to power the blower, computer, thermostat, and two dampers? Just curious if it could power anything else or if I should think about an additional transformer beyond two dampers.

 

[brenndatomu]

Thanks. Excuse my electrical ignorance but your saying the VF transformer should be able to power the blower, computer, thermostat, and two dampers? Just curious if it could power anything else or if I should think about an additional transformer beyond two dampers.

It doesn't power the blower, the blower is 120VAC.
But yes, computer, Tstat, a 2 dampers.
If you feel better about putting the dampers on a separate transformer, I wouldn't argue about that.