1) Good/Bad Fan Designs and Placement. 2) Impact of pwr outages on fans...steps to take

[53flyer]

The combination of a stove manual and recent thread got me thinking about fans:

I read this in a stove's operation manual:
NOTE: On low and med burns (<.80-1.25 Kg/hr) the room air fan should be operated on the lowest setting. On med/high and high burns (1.25-1.90+ Kg/hr) the blower fans must be operated to avoid excessive heat buildup and possible damage to fan blades and electrical components.

1) Does everyone agree that squirrel fans are quieter and last longer than the other type fan with the typical 4-5 blades spinning around?

2) What about manufacturers that have better fan placement irt preventing heat damage to either type of fan?

3) So during a power outage, based on the above note, would you want to ensure you set a battery operated fan in front of the air intakes for the insert fans in order to attempt to keep them cool (has anyone done this)? Either that or run the stove on low until the pwr was back on (hopefully the stove wasn't really hot right as the pwr went out?)?

 

[budman]

Back in September i cleaned and painted the stove and found the main wiring
coming into the junction box burned & bare.This past spring i ran the stove with out
the blower running and think that is what caused this.As far as no power that is one
of the reasons i bought a generator.

 

[velvetfoot]

I took mine out to look at an clean after an unfortunate ember uptake that melted a part of a couple fins.
I don't recall it being too hard to remove.

 

[53flyer]

We've got a few back up fans just in case that can run on rechargeable battery packs. I also heard from a dealer that side fans are better than bottom fans irt longevity but I wanted to see if anyone else heard the same thing. The little plastic blades on most typical 3-4 blade fans aren't that durable or heat resistant though.

 

[velvetfoot]

Why don't you check out how difficult it would be to remove the fan?
The manual would give you a good overview without taking things apart.
Maybe it could use some cleaning as well.
Mine is a squirrel cage on the bottom and it had no problem during a 3 day outage, but you bring up a good point and all stoves aren't the same.

 

[53flyer]

Why don't you check out how difficult it would be to remove the fan?
The manual would give you a good overview without taking things apart.
Maybe it could use some cleaning as well.
Mine is a squirrel cage on the bottom and it had no problem during a 3 day outage, but you bring up a good point and all stoves aren't the same.

Yes, the manual shows the steps and they're not that difficult but it's still a small space to work in that would be a bit of a pain to do 3-5 (or more) times per yr. I was just interested to see if other people had any concerns &/or solutions they came up with (aside from a generator).

 

[Joey]

Thats a great thread. Which stove manual did ya get that info from??? I often wondered the same thing. Does the stove fan always have to run? My insert sticks well out onto the hearth, and at times, I feel I dont need to run the fans when I'm burnin a small fire. But I always run them anyway. Think I will contact the manufacturer and ask them directly. There are always soooo many questions, good thing for this forum.

 

[vtburner]

I dont know about question 1 & 2, but as far as 3 goes, I think I can contribute.

It's A little different scenario than an onboard blower, but still relevant: A while back I had a heat reclaimer on my old stove for about a month. I read in the manual that the reclaimer must be plugged in if the stove is running. It was on a thermostat, so I didn't need to then turn it on or off. Good enough, plugged it in and forgot about it, and it worked great. WELL, one day the power went out, and things unknowingly went awry inside the reclaimer, and when the power came back on, it ENERGIZED MY WHOLE STOVE. I didnt realize this had happened until I went to load the stove and grabbed onto the metal door handle and got a helluva shock and the surprise of a lifetime!

Funny thing is, it didn't short out somehow, and the fan was still working! After considerable confusion, not knowing where this shock could have come from (remember, the reclaimer was new, and whoda thunk it would energize my stove???) and debating whether I was crazy and/or should try the handle again, I finally unplugged the reclaimer, let the stove go out, then tore it apart.

Everything looked fine in the reclaimer, until I stripped back some insulation off a bundle of wires and found the culprit: the hot wire's insulation had melted off and had fused to the bare ground wire inside of the insulation. How this energized my stove while still allowing the unit to function AND not trip a breaker is well beyond me, but it HAPPENED!

SO, I learned that if the manual says you MUST run the dang fan, then run the dang fan; and Definitive Answer to #3: back it up somehow.

 

[YZF1R]

I dont know about question 1 & 2, but as far as 3 goes, I think I can contribute.

It's A little different scenario than an onboard blower, but still relevant: A while back I had a heat reclaimer on my old stove for about a month. I read in the manual that the reclaimer must be plugged in if the stove is running. It was on a thermostat, so I didn't need to then turn it on or off. Good enough, plugged it in and forgot about it, and it worked great. WELL, one day the power went out, and things unknowingly went awry inside the reclaimer, and when the power came back on, it ENERGIZED MY WHOLE STOVE. I didnt realize this had happened until I went to load the stove and grabbed onto the metal door handle and got a helluva shock and the surprise of a lifetime!

Funny thing is, it didn't short out somehow, and the fan was still working! After considerable confusion, not knowing where this shock could have come from (remember, the reclaimer was new, and whoda thunk it would energize my stove???) and debating whether I was crazy and/or should try the handle again, I finally unplugged the reclaimer, let the stove go out, then tore it apart.

Everything looked fine in the reclaimer, until I stripped back some insulation off a bundle of wires and found the culprit: the hot wire's insulation had melted off and had fused to the bare ground wire inside of the insulation. How this energized my stove while still allowing the unit to function AND not trip a breaker is well beyond me, but it HAPPENED!

SO, I learned that if the manual says you MUST run the dang fan, then run the dang fan; and Definitive Answer to #3: back it up somehow.

I don't think it tripped the breaker because it was not shorted to ground. The stove and pipe is not grounded to metal. You were the final link and the juice went through you to ground.

Steve

 

[raybonz]

I dont know about question 1 & 2, but as far as 3 goes, I think I can contribute.

It's A little different scenario than an onboard blower, but still relevant: A while back I had a heat reclaimer on my old stove for about a month. I read in the manual that the reclaimer must be plugged in if the stove is running. It was on a thermostat, so I didn't need to then turn it on or off. Good enough, plugged it in and forgot about it, and it worked great. WELL, one day the power went out, and things unknowingly went awry inside the reclaimer, and when the power came back on, it ENERGIZED MY WHOLE STOVE. I didnt realize this had happened until I went to load the stove and grabbed onto the metal door handle and got a helluva shock and the surprise of a lifetime!

Funny thing is, it didn't short out somehow, and the fan was still working! After considerable confusion, not knowing where this shock could have come from (remember, the reclaimer was new, and whoda thunk it would energize my stove???) and debating whether I was crazy and/or should try the handle again, I finally unplugged the reclaimer, let the stove go out, then tore it apart.

Everything looked fine in the reclaimer, until I stripped back some insulation off a bundle of wires and found the culprit: the hot wire's insulation had melted off and had fused to the bare ground wire inside of the insulation. How this energized my stove while still allowing the unit to function AND not trip a breaker is well beyond me, but it HAPPENED!

SO, I learned that if the manual says you MUST run the dang fan, then run the dang fan; and Definitive Answer to #3: back it up somehow.

You have a ground a ground problem with that outlet feed by the sound of it the breaker would have tripped and protected you! You need to kill that circuit and check that your ground is truly a ground before someone gets hurt or killed.. FYI I am a licensed electrician so I know what I am talking about..

Good Luck!

Ray

 

[woodracerx]

Ray that is what i was thinking outlet he was plugged into is not grounded. some people change out 2 prong outlet to 3 prong and not do anything with the ground lug and i am not a electrician.Mark

 

[YZF1R]

vtburner, did that thing have a three prong plug? I assumed it did not. raybonz is correct, make sure that socket is wired properly.

Steve

 

[vtburner]

It's a 3 prong, grounded outlet. the reclaimer had a ground prong. Everything is good in the box and my house ground is good. I had my Uncle, a Master Electrician, come by to double check everything after this happened and got the all clear. Had him check all the circuits in the house just to be sure.

It is wierd though, but maybe this is important - My all-cast iron stove sits on a big peice of1/8" sheet metal (hearthpad? - the last homeowners weren't too smart) that lies on a concrete floor in the basement. I was standing on that sheet of metal when I touched the handle and got zapped. Now I know diddly squat about electricity, but maybe the way the wires fused somehow bypassed the ground and the whole stove was just part of the hot? whould that even matter? I dunno..... it's a mystery - moral of the story - back up your fan/blower if the manual requires it to be working...

 

[vtburner]

oh another thing - the wire that fused I believe went to the thermostat sensor and not to the actual fan motor... depending on how it was wired in the controller, maybe this was seperate enough from the main circuit to bypass the ground? or maybe thats just a stupid thought hh:

 

[btuser]

oh another thing - the wire that fused I believe went to the thermostat sensor and not to the actual fan motor... depending on how it was wired in the controller, maybe this was seperate enough from the main circuit to bypass the ground? or maybe thats just a stupid thought hh:

If the fused wire went to one side of an open relay on the thermostat, it would trip out when the thermostat closed, otherwise wait untill you came along to give it a path to ground.

Ok, without know the wiring of your stove blower/fan, I'm going to take a guess. You had a short, but not a short bad enough to trip the breaker. The resistance back to ground was high enough to prevent the breaker from tripping, but you came along and provided another shot for that sweet juice to get back to Mother Earth. Or the wire shorting may have been the neutral returning from the blower so what you were getting is the return on the circuit, not the line voltage before the load. Neutrals can kill. Low level faults are where GFCI and Arc-fault breakers come in.

It takes less than .1 amps to stop your heart, but 15-20 amps to trip a traditional breaker. You had a fault that was grounding to to your stove, then back out to either the circuit's ground or through the floor and you got in the way of the path. A GFCI would have registered the difference in potential between what was coming back and reallized current was being diverted through your chest cavity, probably to the floor. If it goes from one arm, through your chest back to the circuit the GFCI will let you die, because as long as it get's it current back its happy!

I've been fried by 277v, secondary line voltage in the neighborhood of 13,000v, but THE WORST shock I ever got registerd 40v on a multi-meter. I grabbed a fridge, touched a pipe, my hands were wet and I hit the floor.

 

[LLigetfa]

Squirrel cage fans work on the principle of centrifugal force. They work better at moving cold air since it's heavier. I advocate moving cold air, not hot air. Hot air heats the motor (inline) and bearings. Hot air cannot be filtered easily.

I use an 8 inch, 650 CFM centrifugal inline blower down in my crawlspace built into a 16x25x48 filter housing. It has a washable 16x25 prefilter before the blower and a 16x25 3M Filtrete furnace filter between the blower and the stove. The blower draws cool air off the crawlspace floor and sends it up through the base of the stove into the room above. The warmed air returns to the crawlspace at the far end of the house keeping the floors nice and warm. The noise of the variable speed blower is muted by a labyrinth built into the enclosure and depending on speed, quieter than my furnace blower.

My crawlspace is a fully insulated drywalled conditioned air space. It is essentially a basement with 4 foot high walls and painted concrete floor. The furnace in the crawlspace draws outside air and so is unaffected by the pressure deficit the blower creates.

 

[vtburner]

oh another thing - the wire that fused I believe went to the thermostat sensor and not to the actual fan motor... depending on how it was wired in the controller, maybe this was seperate enough from the main circuit to bypass the ground? or maybe thats just a stupid thought hh:

If the fused wire went to one side of an open relay on the thermostat, it would trip out when the thermostat closed, otherwise wait untill you came along to give it a path to ground.

Ok, without know the wiring of your stove blower/fan, I'm going to take a guess. You had a short, but not a short bad enough to trip the breaker. The resistance back to ground was high enough to prevent the breaker from tripping, but you came along and provided another shot for that sweet juice to get back to Mother Earth. Or the wire shorting may have been the neutral returning from the blower so what you were getting is the return on the circuit, not the line voltage before the load. Neutrals can kill. Low level faults are where GFCI and Arc-fault breakers come in.

It takes less than .1 amps to stop your heart, but 15-20 amps to trip a traditional breaker. You had a fault that was grounding to to your stove, then back out to either the circuit's ground or through the floor and you got in the way of the path. A GFCI would have registered the difference in potential between what was coming back and reallized current was being diverted through your chest cavity, probably to the floor. If it goes from one arm, through your chest back to the circuit the GFCI will let you die, because as long as it get's it current back its happy!

I've been fried by 277v, secondary line voltage in the neighborhood of 13,000v, but THE WORST shock I ever got registerd 40v on a multi-meter. I grabbed a fridge, touched a pipe, my hands were wet and I hit the floor.

Thanks for the insight... I think my uncle also mentioned he figured the amperage through the short wasnt enough to trip the breaker, or something to that effect... I can't quite remember.


I am going to be sure to check with the manufacturer when I buy a new stove to make sure the electrical is far enough away so the fan doesnt HAVE to be used. I think, after that experience, that it is FAR too dangerous to have to rely on constant power to keep a wood-burning appliance's electricals from burning out. The fire doesnt care if the power is on or not. not to mention, when you need the stove most is when the power is more likely to be off!!