Coalpail.com Forum

Hello All,

I'm interested in a temp controlled switch that has a probe of some sort that one could use in, or on the flue. Something that opens on rise, and adjustable for 300, maybe 350* range.

Thanks in advance.

Dave

They were called stack switches on oil and coal burners, oil has all gone to the electric eye to confirm the fire is lit, and coal seams to have gone to not bothering with them.
Currently you probalby could use a snap switch available in Grainger and place on the outside of your stove pipe.

Thanks, Short Bus,

I found snap disc style switches as high as 350*, but I thought that there might be other options.

I wonder how much difference there is between the inside flue temp and surface? I need a infrared gun....

Dave

They are SNAP SWITCHES, THERMODISC SWITCHES, etc...

any HVAC should have them, EBAY, PEXSUPPLY, COLE PALMER, etc...usually run about $10-20. You can get them adjustable too. I use one for my jacket fan switch.

Probalby about 100+ degree difference between inside and outside the pipe.

I guess it depends on what you want to do with the switch.

WNY,

Understood, I should have mentioner more clearly that I was aware of such switches. I wondered about something with a probe that could enter the flue gas stream.

I'm looking to control a second combustion fan on my "manufactured with a single fan" Kaa-2, but I wish to have a "high limit" control on it, based on flue gas temp.

Thanks.
Dave

Will this help
http://inspectapedia.com/heat/StackRelaySwitch.htm
http://www.valueac.com/hoprressw.html

I am not sure of why you want to control the secondary fan with a stack switch, but the only option that I can think of would be to use a simple industrial temperature controller with a RTD or Thermistor probe in the stack. These type controllers are available from OMEGA or similar suppliers.

The old flue switches of day past are not readily available any more.

Thanks, Gents.

I don't want to fully control the 2nd fan via the stack temp, just open the circuit if stack temp get too high. I admit, it's probably another exercise in buy, try and re-shelf. The thermisters and such are a tad pricey. Since it could be just an experiment, a $10 "snap disc" looks to be the best option.

Thanks much for your input.

Dave

At the temperature range that you are looking at, it will be hard to find a device that trips at 350 deg. f. without going to an industrial control.

Since you are in the experimental mode, why not try a oven thermostat. Maybe you could find an appliance dealer that would let you salvage one out of a throw-away stove.

Steamup,

I hadn't thought of something from an oven. i'll look into that.

I don't know if they'd live long, but there are 300 and 350* snap switches;

http://www.grainger.com/product/Snap-Disc-Control ... vc=IDPRRZ1
http://www.grainger.com/product/Snap-Disc-Control ... vc=IDPRRZ1

Something with a probe [and affordable] would be better, but I don't know about how such devices would live in that enviroment. I still need to get a good infrared gun and check the outside flue temp. My cheap BBQ gauge in the flue says 375 ish running hard for 20 minutes or so with a normal amount of air, but giving the fire only a little more air will make it go 400+ in a hurry.

thanks
Dave

Like *steamup* said:

**Broken Link(s) Removed**

McGiever [and others],

You guys are the best. That looks ideal. Just clamp the bulb to the flue, and the switch would be back away from the heat. And my price range too!

Thanks for taking interest in this, another whacky experiment.

Best Regards,

Dave

I did a little mod on my VF3000 boiler like you are looking for.
I wanted to know if I had a out fire and I thought about monitoring the stack temp, but the stack temp is pretty low when the boiler is idling.
So I thought it might be better to install a snap switch on the outside of the boiler on the stoker assembly.
the stack switch is mounted on stoker wall where on the other side of the wall are the hot coals.
I used a L140-20
here is a link to the specs
http://www.drillspot.com/products/446908/Supco_L1 ... Thermostat

I have the snap switch contacts connected to a flood monitor, so when it gets below 120* the contacts close and sound the flood monitor.

here is a link to the flood monitor.
http://www.homedepot.com/webapp/wcs/stores/servle ... 038838-_-x

this has worked well for about a year now.
I will post pictures below.