Shutdown UPS backup test turned real.

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FirepotPete

Minister of Fire
Oct 25, 2010
735
Titletown U.S.A
So yesterday I planned on shutting down my stove and cleaning it while the weather was mild and before the cold front that came in overnight got here. I also figured it would be a good time to do my irregularly scheduled testing on my UPS system. This is my homemade, thrown together with what ever parts I could afford and find on the cheap, not a store bought system.

So I get out my meter and open the circuit breaker that the stove is on, the transfer switch did it's thing and the stove continued to run while I checked voltage and amps after the regulator and before the regulator. All worked just fine.

Like a lot in the Midwest we were experiencing high winds, constant 30-40 mph gusts here around 50+, a lot of power outages all around. I was thinking now would be a good time to actually test what the stove would do without power all together with the high winds as I've read people having problems with high winds and their stove back drafting into the house.

So I reset the breaker and put the transfer switch to manual/off. Went out to the garage for a few minutes and while out there the light went off. Never had a problem with it before...sure enough our power got knocked out, power pole had snapped and about 25,000 lost power in the area!

So I go back in the house and start to watch the stove. After ten or so minutes I notice slight wisps of smoke coming from under where the ash pan and manual draft are, nothing major but still there. So after checking it out I see that the rails that the draft slide in could be tightened later and make it more air tight. So I think I might as well pull the clinker and stop the smoke. So I close my OAK brass ball valve, the wisps of smoke stopped.

I could even open the manual draft an inch or so without it back drafting, anything further and it would smoke into the house.

Why closing that OAK under high winds from outside stopped the smoke I don't know for sure why. I opened the OAK again and sure enough the smoke started again. With the differential pressure being greater outside the house it just doesn't seem it should work like that but it did. The only thing I can think is that the warmer air in the house expands better than cool/cold outside air and finds its way around the damper into the stove and then creates a draft out the exhaust.

Surprised me, I never would have thought it would work that way. Perhaps in the future I'll have to try it again with high winds from a different direction and see if it acts the same.
 
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So your back up power only supplies the stove?

And it kicks in automatically when the power goes out?

Was the exhaust fan running on the backup power when the street power went out and you got the wisps of smoke?

I got one of those computer power backup towers and whenever I test it (haven't in a while) the fans considerably slow down to the point that negative pressure drops. Might be your case - a slower exhaust fan with the OAK air pushing in causes spillage.

Cool that you have a shutoff valve for the OAK. Never thought of that.
 
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So your back up power only supplies the stove?

And it kicks in automatically when the power goes out?

Was the exhaust fan running on the backup power when the street power went out and you got the wisps of smoke?

Yes the stove is the only thing I have plugged into the power strip all the time. If the power would go out I can run an extension cord for the frig if needed, or anything else I want so that if the power goes out in the summer I can access it easily. My main concern is heat in the winter.

Yes the transfer switch senses no line voltage and switches over to my battery back up. I have four gel-cell batteries that are made for golf carts, so I can go at least 24 hours just running the stove.

No the exhaust fan wasn't running as I had set the transfer switch to manual/off so it wouldn't switch to the batteries when I opened the breaker, but I didn't need to open the breaker as Mother Nature did it for me. :)

I guessing, and that's all it is, a guess, that the smoke was trying to go through the stove and out the OAK. The exhaust is to the west and that's the wind direction that day, the OAK is to the south so I'm thinking that it was taking the path of least resistance, if that makes sense.
 
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We had a similar outage down here -- first one in about five years. The electricity was off for seven hours. The boiler wasn't running when the outage occurred, so no smoke to worry about.
 
Yes the transfer switch senses no line voltage and switches over to my battery back up. I have four gel-cell batteries that are made for golf carts, so I can go at least 24 hours just running the stove.

I need batteries like that. My power went out this morning for 3 hours, and the 6 year old UPS backup lasted like 3 minutes (batteries dead). Now it is just a fancy surge protector only.
 
Winds coming around the corner of the house causing a negative pressure near the OAK location outside? Need to give it a try when winds are lower and then again from a different location...