Thermostat / Switch

[Brian_Bailey]

Can anyone point me towards a supplier of a thermostat that I can use to turn on & off a space heater maintaining 140* F. ?

TIA ....

[Larry]

Check out this thread Brian.

https://forestryforum.com/board/index.php?topic=11490.0

Constant use since installed and still working good...turns a 1 1/2 HP fan on and off to keep me from overheating.

[Murf]

Brian, any liquid type thermostat will do the job, the bi-metalic spring type with the little bulb of mercury. For an electric space heater, you may need a special high power 'stat, or relay to handle the load on a regular one.

The trick is to not tell it you want it to go to 140°   :D

If you don't mount the thermostat perfectly plumb, like they tell you to in the instructions, it will affect the point at which the mercury runs to the other end and shorts the two contacts.

You just have to do a little experimenting to get the engle right. Use just one screww and barely tighten it, then set the thermostat for the center of it's range, and with the heat at (or real close) to 140° turn it till the ball of mercury is just at the point of running down the other end. Then just monitor the setup to see if it's keeping it at the right temp. over a period of time.

As a hint, some thermostats also have a "range" adjustment, this determines how close to exactly the set point it stays, or if you will, how far over or under it will allow the temperature from the set point. Basically fewer longer runs of the furnace, or more frequent, shorter runs of the furnace.

BTW, you can also do this in the opposite direction, to allow you to set it closer to freezing than say 50° which is as low as most 'stats go. I did this, and then connected a relay to a strobe light all on a scrap of plywood. When I leave the house for any time in the winter, I put this setup in the side window, if the temp. in the house drops below a safe point, the strobe starts blinking in my neighbours direction. That way they can tell at a glance if everything is Ok or not. Makes it real easy to keep an eye on things.  ;)

[beenthere]

I bought mine at an Ace hardware store.

Ace # 42727

It switch's the 115V line voltage on/off from 50° to 90° F


Whoops!  Not what you want.....

[Brian_Bailey]

Larry, your digital thermostat is just the critter I'm seeking. Thanks

I made a 2' x 2' x 8' plywood box that I can assemble and disassemble as the need arises.

I'm using it as a sterilizing chamber for found chunks of carving wood.

I bought a cheap 1500 w space heater and disabled the over temp switch so I can get the 140* F. needed to kill any unwanted wood munchers residing in the wood.

I've cooked a couple of batches so far but have to babysit the temp in the chamber and manually turn on & off the heater. A real pain!

I like your suggestion Murf, as I can easily get a household thermo like the one beenthere referred to.

The only problem is I would have to calibrate it everytime I reassembled the chamber.

Thanks for the replies.

[wiam]

I was going to suggest that thermostat.  I use one on my chicken scalder to run an electric water heater and it works great.

Will

[Murf]

Brian, I hear what you're sayin', but as with most things, there's a trick to it.

Mount the 'stat as I described, but mount it that way on a small (6" x 6"?) scrap of 1/4" plywood. The plywood then becomes a permanent part of the 'stat, and the 'stat becomes permanently "re-calibrated" to the temp's you want.

Then all you have to do is mount or dismount the little piece of plywood carrying the 'stat.  ;)

[Brian_Bailey]

Thanks Murf,  that would certainly solve the re-cal. problem.

[low_48]

I'll have to check again, but I saw a pretty cheap switch at Lowe's the other night. It is used to turn on attic fans for the house. I can't remember what the range setting was.

[beenthere]

low_48
Would that mean it is normally off (open switch) below 'set point' and switched on (closed switch) above the 'set point' ? 

i.e. for cooling.  ???

[Ga_Boy]

Brian,

If you are still looking for a thermostat; try this one.

White Rodgers

Model # 24A01G003S1

The MSC stock number is 05287701; the catalog I have lists the cost as $67.36

This unit is a 24 V control with a SPDT normally open contact.

Input voltage is up to 240 VAC,

As for a source of supply try MSC Industral Supply 800-645-7270

They are open on Saturdays 9AM - 4PM EST, Monday to Friday 7AM -11PM

Web address is Industral Supply Link





Mark

[Brian_Bailey]

Thanks for the info.

I ordered the thermostat that Larry described. Should have it sometime next week.

I'll post some pictures of the little mini-kiln / sterilization chamber that I cobbled up to cook small blocks of wood so they are free of insects.