kitchen hood: Problem wiring my power-open damper.

[mikeBeginner]

Hi. novice here.
I am wiring a relay w/ kitchen hood: it will first power-open a damper before the
fan can get power to run. It spring closes. The hood has lights, that are independent of the fan, ie their own on/off.
Problem: the wire I need to tap, to route thru my relay is always 'hot', even when the fan is off.
So - as soon as I plug in the fan (but not even turn it on), I watch as line voltage goes from this wire, to my 24VDC transformer, to feed both the relay and the 24VDC power-open damper. The damper opens, etc.
What would I see if I open the fan housing?
Can I open up the fan housing and hopefully find a spot that is 'after' the on-switch that I can tap?
My diagram:
http://www.kitchenhoods.ca/catalog/images/Wiring218-1.jpg
Disregard 12V transformer. My model has GU10 line voltage (not MR16s). Lites ARE independent of the fan.
My hard-copy drawing also notes:
Brown-4-fanSpeed 6, Green-5-fanSpeed 5, ..., down to Blue-9-fanSpeed 1.
Again- my problem is that the black wire (2nd one down) is hot always -
Do you think I can I find a point inside the fan housing where I can be 'after' the on-switch ?
I saw johndearmond.com pic where 'variable speed' wires were wrapped into the innards - I'm hoping my hot wire has some clean connections?
(Chinese made, no info on the motor; Seems like Id open sides of the fan to look for the wire - ie no nice entry where the wires enter the housing.

Thank you for advice.

 

[duke37]

I do not fully understand your description. However, you need two wires to a switch.

Should the white line in go to the switch and a white wire from the switch go to the gubbins? The switch will then turn everything off.

 

[shrtrnd]

I'd wire the damper to the power to the fan.
When the fan turns on, the damper starts opening. It should only take a couple
of seconds to open the damper, and shouldn't be much of a problem for the fan.
It isn't exactly what you want, but easy to figure-out, and should work.

 

[mikeBeginner]

duke37:
I do not fully understand your description. However, you need two wires to a switch.
Should the white line in go to the switch and a white wire from the switch go to the gubbins? The switch will then turn everything off.

A: Colors of wires are confusing. The L N on diagram not necessarily Line/Neutral. Anyway - from plug-end, that black is my 'hot'. If I follow your comment, you're expecting to see a 'hot', a 'white-return', and speed-control wires going up to fan. But I just have 2-yellows to capacitor, the always-on-hot-black, and then 6-speed-control wires. I wondered if 6 speed-wires are my 'returns', and IF they are cumulative, then I might tap lowest speed Blue one. (Someone told me its unlikely they work cumulatively).

shrtrnd:
I can do what you say. The damper opens always, even if wife just turns on lights without any fan. That is good enough. Problem is - as soon as I plug in the fan, power gets thru to open the damper - even if neither lights nor fan are ON. Final fix may be to add a manual switch that turns my outlet on/off. Then rely on wife to manually turn it off after she's done using lights and/or fan. OR - Should I open that housing and look for my point to tap as noted originally? ie what the heck is inside there? Worth trying?
Thank you so much !

 

[shrtrnd]

I'm with duke37. YOU know what you want, but WE'RE not real clear about what you're
trying to tell us.
I'm thinking (because I don't know) that you have a separate switch for the light and the fan (with multiple speeds on the fan). Your damper is just tied to input power to the light/fan.
I'm wondering what you mean about 'plugging in the fan'.
What we tell you is based on what we think you mean, and we're not sure about that.
I would think the manufacturer designed the circuit deliberately to open the damper as
you described: anytime either the fan or light is activated.
It's up to you if you want it to act differently.
Your solution to add a manual switch to turn the outlet on and off seems reasonable.
If you open the hood assembly, you'll be able to trace the incoming power, thru the
switches, to the light, fan and damper. But it's probably a pain to get inside of it unless
you really think you need to.
If you know exactly what you want to do and still need ideas:
Tell us how the system works. Number of switches, and how the unit is getting power.
I THINK I can guess what's in there, but it'd be a guess.
Good luck. I'm sure you can get the system to do what you want. We just need a
little clearer information of what you've got, to decide what to do with it.

 

[duke37]

The motor speed is likely to be controlled by resistors. The common terminal will be 3 black and the other connection to the motor will be selected down to 9 blue. The resistors are located in the motor housing so that they are cooled by the air flow.
An alternative would be tapped motor winding, you could check this by measuring resistance across the motor.

You have not commented how you only have one wire to the switch.

Duke

 

[mikeBeginner]

Duke37, I think you got what I am attempting to say...

Thank you again. Clarifications: Duke37 - you're spot on.
http://www.kitchenhoods.ca/catalog/images/Wiring218-1.jpg

In the diagram: If I plug the hood's 3-prong plug into my wall, I 'hoped' that the black wire from Terminal-3 up to the Motor would have no voltage unless I turn on the Motor by pressing the digital-switch at front of the hood (its 1 button, repeatedly pressing it lets me increase from 1 to 6). (Lights are separate switch.)

However, I cut this wire, say Side A closest to terminal 3, side B closest to Motor.
Now, when I plug into the wall, I immediately measure 120V on Side A, even though I have not turned on the Motor at all. The 120V goes the Motor and sits, whereas I'd have expected the circuit board to only let power go up to the Motor housing IFF I turn on the Motor.

Background:
I have a Hoyme 24V power-open (spring-close) damper, and a 24V controller, and a 120-to-24 transformer.
Ideally, this black wire would become hot, ONLY when I turn on the Motor.
Then, Side A routes both to the transformer, and also into the controller.
Controller sees this 120V 'request', so it is triggered to power-open the damper.
Damper hits its end-switch, signalling controller to allow 120V back out, and up to Side B.
Motor turns on.
I turn Motor off, and everything goes off, spring closes the damper.

duke37: Your 6-resistors explanation seems right. So, I wanted to try to open the Motor housing and maybe find a point where that black wire does indeed sit in an off-state til Motor is turned on.
Can one maybe tap the lowest speed Blue in the hopes that the wires cumulatively become hot as one increases speeds - ie Blue has 120V so long as any speed 1-6 is ON ?

I will try to take down the hood tonight - open the sides of the fan - see if I get lucky finding black wire in off state.
Thank you again very much -

 

[mikeBeginner]

I give up. Tying in via the hood lights.

Well - for future readers - here's my final comment:
Motor takes in air on both sides, and motor housing is sealed between these intakes.
I'd have to unscrew the main drive nut on 1 or both sides to see inside, and maybe find
a point where my hot terminates/rests awaiting an ON.

No guts to take this on.
I asked few people if by chance, the motor speed resistor wires might work additively / cumulatively, such that Blue could be used to tap. No replies yet - but I assume this is not
so, but rather each speed control wire takes turns as one increases fan speed.

I will tie-in to the hoods lights per neonJohn's guidance. Damper will open if just lights are used - so be it. And, if one wants to run the fan, one must first turn on lights to get damper to open, and release power to fan motor.

Moral to the story - see good diagrams before you buy - and Spagna Vetro hoods are not good candidates for this type of hook-up.

Thanks .

 

[duke37]

I can not get at your second link.

Do not go into the motor, you will find nothing of use there and may cause damage. The windings and capacitor should be treated as one unit and not be fiddled with. I do not know what your motor consists of but it seems to be similar to a central heating pump motor which has a resistance in series with the motor, tapped in various places for the speed control. The resistance will be maximum at the lowest speed (blue). The black will be at the other end of the chain. This should be neutral but you have apparently got your mains reversed. The motor connections are to put power into the motor and NOT to take power out.

 

[mikeBeginner]

If Mains reversed - can I correct that somehow?

I am in process of getting a stand-alone switch to sit outside the hood. It will power my damper, and once damper is open, it will give power to the Motor.
So wife must manually hit this switch THEN hood switch, vs solely the hood-switch.
But - lights can be on/off without damper involved.

Reason for the above is -
After my prior post, I found that my lights (on their own switch) are same as Motor. When I plug unit into the wall, before I turn any switches on, I can measure 120V after my light bulbs. So, in laymens terms, my voltage enters unit and has access right on thru the light bulbs, and is only 'stopped' or switched AFTER the bulb at the circuit board.
So - idea to run my damper off lights hits same problem as cutting the black to Motor.

Now - "Mains is reversed". Can I correct this? I just thought it was a poor design that I could not affect, ie that power is not controlled before entering the Motor or lights but rather after.

Can I fix reversed Mains?

 

[duke37]

The wiring is a loop and a switch at any point in the loop will turn the current on and off so it will work with the mains connected either way round. It is safer to put the switch in the live line as shown in your first diagram. Did you wire up the power plug yourself?
In the UK the wiring colours are strictly regulated