Draft door question

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Old 05-14-12, 06:52 AM
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Draft door question

I got a ~1985 wood boiler for free from my inlaws. I got it set up with a lot of help from the group here...thanks. I still have one question...

The draft door is a horizontal slide. I thought that could hook up a honeywell M847A motor and slide it open when the aquastat called for heat...on the other end I had a stiff spring that would make sure it closed when the temp was up or the motor lost power. This worked for a couple of months but now the M847a is no longer working.

Did I burn it out with too strong of a spring? It seemed that the motor had little trouble over-coming it... I see that the motor came with a lever device....I was not sure how that worked so I went with the mechansim described above. How am I supposed to use that lever.

Is there a better way to control a horizontal slide draft? I have been all over online looking for examples but I cannot find any.

I am going to order another one (m847a)...but I want to get a little more infomation so I do not burn this one out right away.

Thanks for any help.

Hartwa.
 
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Old 05-14-12, 06:10 PM
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I don't have the M847A motor in my (old) Honeywell book but you might have caused it to burn out due to not allowing the full stroke of the motor.

I don't understand what you mean about not using the "lever" on the motor. How DID you connect the motor to the damper if not via a rod between the damper and the "lever" (really bellcrank) on the motor?
 
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Old 05-15-12, 07:04 AM
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The motor has a wheel on it. I used the wheel like a sprocket and connected a light chain to the door. See image below.

This motor came with a lever...a thin peice of steel. I am not sure how I am supposed to hook this door up other than what I have already done.

Do you think it my spring was too strong it did not allow the motor to complete the stroke? I would like to think of a way to do this without the extra spring...let the return spring in the motor shut the door. In reality...the way that I did this make the motor overcome two springs...the internal one and the one that I added.Name:  door.jpg
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Old 05-15-12, 03:14 PM
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Hart, have you got the damper motor tied into the 'high limit control' as well as the thermostat wiring?

I'm looking at this PDF:

http://customer.honeywell.com/techli...5C-10110EF.pdf

There are models of this motor that come with a chain, so that use is permitted.

Is the motor assembly mounted such that it is always within the temperature rating of the device? ( max 125F ) Maybe excess heat kilt it? You might need to fashion some form of 'radiation shield' to keep the thing cooler?

Mounting Position: any position except when using chain linkage where actuator wheel should be vertical (see Fig. 3).
Nominal Angular Rotation of Wheel: 45 degrees
Is that all the wheel moves? and it's enough to open the damper fully?

Does that device use the same Synchron motor that's in the 8043 zone valves?

Torque rating looks to be 30 in oz. Do you have a fishing scale? How much force to pull the damper open with the spring you have on there ?
 
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Old 05-18-12, 06:54 AM
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Thanks for the help.... i found the problem with the old motor. Actually it was not the motor at all. The gear that comes out of the motor was stripped off the spindle. So the motor was turning and the spindle was turning inside the gear.

I tried some strong epoxy I use for golf clubs but that did not hold. I carefully got a spot weld on it and it it holding now. I should get the new one today too....I will keep using this one tell it is dead...dead.

Thanks for the help...

Hartwa.
 
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Old 05-18-12, 02:26 PM
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Do pay attention to the question I posed about the temperature... and if it's getting too hot, fashion some sort of 'radiation shield' out of aluminum sheet to shield the box from the heat.
 
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