stack thermometer

[the old guy]

I just replaced the old galvanized stack on my evaporator with a new stainless steel flue. Problem is my old magnetic stack thermometer will not adhere to the stainless. I can't seem to locate one that indicates it will "stick" to stainless. I'm sure they are out there. Any ideas???

the old guy

[emo]

To make stainless "stainless" they mix enough alloys in so that it no longer rusts and it also looses it magnetic properties. When I worked in Indutrial Controls, we could tell the truely stainless panels when you could not get a magnet to "stick" to it. You'll probably have to switch to an insertible temp probe.

[Haynes Forest Products]

Or put a chunk of iron on the back side of the stack you can rivit it in place. It will act like a heat sink and will give a better consistant reading. If you conture it to the shape of the stack and keep it tight so crap wont build up between the stack and the iron it will stay accurate. You can get the type that you drill a hole into the stack and it reads the gases not the metal.

[maple flats]

I think the insertable type are more accurate anyways. Find one with a probe to insert, drill the hole snug and it will stay.

[BryanEx]

I think the insertable type are more accurate anyways. Find one with a probe to insert, drill the hole snug and it will stay.

These have been recommended before on Maple Trader;

http://www.condar.com/probe_meters.html

[stoweski]

Good timing. That's exactly what I've been looking for. Wasn't interested in the magnetic type.

Thanks!


These have been recommended before on Maple Trader;

http://www.condar.com/probe_meters.html

[the old guy]

GOOD IDEAS YOU GUYS. I HAVE CONTACTED CONDAR AND THEY WANT TO KNOW WHAT I FOUND. I AM GOING TO SEND THEM YOUR REPLIES. I THINK THEY WILL BE
IMPRESSED.

the old guy

[markct]

i have a stack thermometer from a cleaver brooks boiler that came from a big building, it was being scrapped so i unscrewed the thermometer from its half inch pipe thread bung and mounted it with a pipe flange screwed to the my stack, it has about a 6 inch stem and reads up to the 800 deg range i think, altho it often goes a bit above this its not realy a big deal its just for reference anyhow not an exact number

[Bucket Head]

A while back there were photos on here of a pyrometer mounted in the stack. A pyrometer measures exhaust temperature on the road tractors. The guage was mounted remotely and the probe was inserted in a small drilled hole on the base stack.

Steve

[Flat47]

I grabbed an of insertion type thermometer off of a b-b-q grill at the dump. It only goes up to 800, but that should be fine for me. Plus, it was free.

[WESTVIRGINIAMAPLER]

Good timing. That's exactly what I've been looking for. Wasn't interested in the magnetic type.

Thanks!



The flue guard from Condar in the above post and link has a magnet on it with a probe and I have a Leader Stainless stack and it adheres to it great and you really have to pull on it to get it loose.

[Flat Lander Sugaring]

I have been reading recently about stack probes. Natural fired wood arch is like 650 to 800. Forced airarch is 800 to 1000. I would have to say to many times past the max might mess up the reading.

[the old guy]

HEY BRANDON, I JUST ORDERED THE FLUEGARD FROM CONDAR. DID YOU USE THE EYELET TO INSERT THE PROBE? OR..JUST DRILL A HOLE IN THE STACK AND NOT USE THE EYELET TO INSTALL THE PROBE?

the old guy

[WESTVIRGINIAMAPLER]

HEY BRANDON, I JUST ORDERED THE FLUEGARD FROM CONDAR. DID YOU USE THE EYELET TO INSERT THE PROBE? OR..JUST DRILL A HOLE IN THE STACK AND NOT USE THE EYELET TO INSTALL THE PROBE?

the old guy

Not sure what you mean by eyelet?? I drilled a small hole just big enough for the probe to go in and pushed it into the stack and the magnetic holds it really nice and tight even to my stainless stack. I really like it a lot as Jon(Tapper) put me on to one a few years ago.

[the old guy]

I THINK WHAT IT IS BRANDON IS A SMALL BUSHING YOU DRIVE INTO THE STACK AND THEN THE PROBE FITS SNUGLY INSIDE IT--ANYWAY THAT'S WHAT THE INSTRUCTIONS ONLINE LOOK LIKE. GUESS I'LL FIND OUT WHEN IT COMES.

the old guy

[SeanD]

Hey Old Guy,

How did your thermometer work out? I'm having the trouble that you anticipated in your previous posts. I followed the directions exactly and the thermometer just dangles. It seems like the magnet is not strong enough. I'm definitely not getting the pull that Brandon mentions. Even with it in my hand, it comes apart with a gentle pull.

In hindsight, I wish I hadn't followed the directions. It said to drill a 1/4" hole, but that gives it too much play around the bushing.

Sean

[SeanD]

I contacted Condar about the trouble I was having and they responded that this thermometer is meant more for double wall and that the dangling I was having couldn't be avoided.

It's too good a thermometer to give up on it, so I found a second magnet to add to the assembly so that one magnet pulls from inside the stack and the second pulls from outside the stack.

The result? The thermometer snapped into place firmly in the hole. This would be an easy and cheap add on, so I'm going to pass the solution on to Condar.

I had the extra magnets kicking around from a unit I teach on magnetism. I can't remember where I picked it up, but it is a pretty common type in hobby magnet kits.

The picture below shows how I arranged the magnets. The magnet on the bottom of the picture is just another view of the second magnet I added.

Sean

[WESTVIRGINIAMAPLER]

Good solution. Only thing I can figure is maybe you drilled the hole too big?? I have a stainless Leader stack and my thermometer jumps right onto it nice and tight, so not sure why you are having so much trouble. Another thing you might do is to attach a small piece of regular steel or a washer to the magnet would stick to it. I take mine off every time I lift up my hood with my pulley system.

[maple flats]

Before I had air over fire I got temperatures as high as 1250 at times. Now with air over fire I stay in the 650-850 range depending on where in the fueling cycle I am. I am putting less heat up the stack wasted.

[the old guy]

I used a piece of galvanized flexible strap iron, drilled 2 eighth inch holes, used two self drilling stainless screws to attach the one-inch piece of strap iron,then used a three sixteenth bit to drill the hole to insert the thermometer. Then the surprize came this past weekend. We were swamped with over fourteen hundred gallons of 2 to 2.4 percent sap. When we started to boil we hardly had to use the forced air unit. I had added 4 feet to the new stainless stack (from twelve to sixteen feet) --what a difference! The "increased draw" sent the evaporator stack temp to 900 - 1000 on the new thermometer with no fan, we noticed a significant drop in the amount of wood we used, the gph was almost the same (30 - 35). Was it the additional length of the stack, or did the stainless metal stack make a difference, we did not know!-- we had the stack rolled using 16 ga stainless sheet metal. Whatever, we boiled over 1400 gallons of sap in three 12 hr days finishing up in the morning of fourth and made about 31 gallons of really good looking syrup --the only time we used the air was to blow out the fire when we had to shutdown.

The old guy

[SeanD]

I'm pretty sure it was your additional stack length. Like you, this is my first season with stainless stack, but I had the same effect you had last year when I went from 14' to 18', though I also went from 6" to 8" stack. The increased draw is huge.

Sean