cheap line-voltage thermostat from homedepot

the operating range is 50°F to 100°F, which is narrower than the thermostats you can get from your LHBS for $50. But at a price of only $27 it seems like a pretty good deal for a line-voltage thermostat if you are looking for one to control your fridge or whatever.

I can't get a link to work, but seach homedepot.com for "ductstat".

-walker

50F-100F will not be sufficient for breweing lagers since you may have to hold the amboient temp at 47 to hold the fermentation temp at 50F.

But for some line voltage thermostats the temp can be offset to match the desired temperature range. The like voltage thermostat that I have has a small screw which which I can shift the themperature range.

Kai

King Kai said:

50F-100F will not be sufficient for breweing lagers since you may have to hold the amboient temp at 47 to hold the fermentation temp at 50F.

But for some line voltage thermostats the temp can be offset to match the desired temperature range. The like voltage thermostat that I have has a small screw which which I can shift the themperature range.

Kai

Click to expand...

agreed.. it's not perfect... but if you only brew ales (which I'm guessing most people here do), this would be perfect and costs $15 to $20 less than the alternatives from the brew shops.

-walker

i feel like an idiot, but i don't get it.... you plug your fridge into this and plug this into the wall... then you set your desired temperature -- say 60®F... without a probe reaching into the fridge to measure that temperature, how does it know when to cut power? it seems like the probe for this is internal/attached to the unit, making it good for controlling the fan that it's designed for -- because the fan would affect the ambient temp.
please set me straight if i'm not making sense...

Lou said:

i feel like an idiot, but i don't get it.... you plug your fridge into this and plug this into the wall... then you set your desired temperature -- say 60®F... without a probe reaching into the fridge to measure that temperature, how does it know when to cut power? it seems like the probe for this is internal/attached to the unit, making it good for controlling the fan that it's designed for -- because the fan would affect the ambient temp.
please set me straight if i'm not making sense...

Click to expand...

it's not clear from the description if the thermal sensor is housed within the box, but... even it it IS, you can put the whole damn thing into the fridge and run yoru power cords into the fridge to plug into it.

-walker

Walker said:

it's not clear from the description if the thermal sensor is housed within the box, but... even it it IS, you can put the whole damn thing into the fridge and run yoru power cords into the fridge to plug into it.

-walker

Click to expand...

yeah, i had considered that....
there's no conspicuous external probe in the picture, so i just assumed there wasn't one...
also, i don't know how well 2 running cords out of the fridge will work...

Lou said:

yeah, i had considered that....
there's no conspicuous external probe in the picture, so i just assumed there wasn't one...

Click to expand...

yeah, I assume there isn't one either, but you never know....

Lou said:

also, i don't know how well 2 running cords out of the fridge will work...

Click to expand...

Should work fine. I've curently got one power cord and one temp probe running out of the door of mine and it seems fine. The flexible, magnetic seal on the fridge door forms around them pretty well.

-walker

Walker said:

it's not clear from the description if the thermal sensor is housed within the box, but... even it it IS, you can put the whole damn thing into the fridge and run yoru power cords into the fridge to plug into it.

-walker

Click to expand...

running the power cord into the fridge will create a bad seal on the doors. This and the limited temperature range may not be worth the $20-$15 savings you get. It's different when you get it for cheaper on E-bay and plan to modify your fride anyway. Then you can install this in your fridge.

Kai

devil's advocate:

King Kai said:

running the power cord into the fridge will create a bad seal on the doors.

Click to expand...

not on my specific fridge, but I see your point in general.

King Kai said:

This and the limited temperature range may not be worth the $20-$15 savings you get.

Click to expand...

This depends ONLY on what you brew. Yes, it's more limited than the one I have from the LHBS, but... the range imposed by this cheaper device would not get in my way at all. If anything, I could say that the one from the LHBS has TOO wide of a range for my uses. I only need temps between 55 and 72 degrees, so how is a $50 thermostat that goes from 30°F to 100°F better than a $27 thermostat that goes from 50°F to 100°F????

-walker

I'm familiar with these. The sensor is inside the housing and most of them are designed for heating applications. I used one in my fermentation box to control a small electric heater, as I've lived in colder areas most of the time. (and I don't lager)

There is a version available that is used to control evaporative coolers that would work with a refrigerator, but I see two problems: the cord problem and cooler thermostats have really huge dead-bands, about 10 degrees. By contrast, my electronic control can be set down to a one degree dead band.

Walker said:

I only need temps between 55 and 72 degrees, so how is a $50 thermostat that goes from 30°F to 100°F better than a $27 thermostat that goes from 50°F to 100°F

Click to expand...

Given that intended temp range, there is no big advantage of the $50 ones, except some convenience and the dead band. The latter may be problematic if it is more than 5F.

Kai

I went in to HD tonight to pick up some siphon line and hose clamps, so I walked down the aisle with the thermostats to see if they had this one and whether the temp sensor was on a long lead or not (I had not yet seen david's post to the contrary).

Anyway, they did not have this one in stock, but I noticed a 'regular' analog thermostat marked for $9.95, rated up to 300V-AC, and marked 'heat only' since it only triggers when the temp is above the set-point and not below it.

I went ahead and bought it since it was so cheap (turns out it was supposed to be $18, but it was mismarked and I got it for the lower price), brought it home and hooked it up to my lamp. Works great. I don't need it at the moment because it was about 75°F today, but that's beside the point. I would have been more fun to build it out of little pieces, but... damn thermistors! I do plan to modify it because (for some reason) the thing requires 2 AA batteries. Doesn't make sense when there is a perfectly good line-voltage source RIGHT THERE FOR USE.

Interestingly, when I was hooking it to the cord to plug it into the wall I noticed that the PCB inside was marked at the bottom with HEAT and COOL, and there was a resistor hooked to the HEAT side. This makes me think you could move the resistor to the COOL side and reverse the polarity of the trigger.

The temp range is is 50°F-100°F, so not good for lagers, but fine for ales.

-walker

Walker said:

Anyway, they did not have this one in stock, but I noticed a 'regular' analog thermostat marked for $9.95, rated up to 300V-AC, and marked 'heat only' since it only triggers when the temp is above the set-point and not below it.

I went ahead and bought it since it was so cheap (turns out it was supposed to be $18, but it was mismarked and I got it for the lower price), brought it home and hooked it up to my lamp. Works great. I don't need it at the moment because it was about 75°F today, but that's beside the point. I would have been more fun to build it out of little pieces, but... damn thermistors! I do plan to modify it because (for some reason) the thing requires 2 AA batteries. Doesn't make sense when there is a perfectly good line-voltage source RIGHT THERE FOR USE.

Interestingly, when I was hooking it to the cord to plug it into the wall I noticed that the PCB inside was marked at the bottom with HEAT and COOL, and there was a resistor hooked to the HEAT side. This makes me think you could move the resistor to the COOL side and reverse the polarity of the trigger.

The temp range is is 50°F-100°F, so not good for lagers, but fine for ales.

Click to expand...

Great find Walker.

You may want to open it and see if you can actually shift the temp range.

Kai

There is nothing there to facilitate adjusting the temp range, but the PCB is pretty darn simple (not much different than the schematic I posted in a different thread last week I believe), so I'm sure it could be adjusted.

The only thing I want do to it is snip off the thermistor that's inside the casing and put it on a long lead so that I can keep the thermostat outside the fridge and the probe inside.

This should save a decent amount of electricity compared to my previous set-up of always having the light-bulb on, plus I can now use a 100W bulb instead of the 25W sice it will only be used when needed.

-walker

Walker said:

There is nothing there to facilitate adjusting the temp range, but the PCB is pretty darn simple (not much different than the schematic I posted in a different thread last week I believe), so I'm sure it could be adjusted.

The only thing I want do to it is snip off the thermistor that's inside the casing and put it on a long lead so that I can keep the thermostat outside the fridge and the probe inside.

This should save a decent amount of electricity compared to my previous set-up of always having the light-bulb on, plus I can now use a 100W bulb instead of the 25W sice it will only be used when needed.

Click to expand...

Yeah, If it is an electronic thermostat then you will have a hard time shifting the temp range. unless you find the resistors that you would have to change.

Kai

King Kai said:

Yeah, If it is an electronic thermostat then you will have a hard time shifting the temp range. unless you find the resistors that you would have to change.

Kai

Click to expand...

It's electronic. As for finding the right resistors to change... there are only a couple of them on the PCB in total. It should be easy to tweak it if I ever decide to.

I'm going to remove the need for AA batteries and put the thermistor on a long lead this weekend, but that will just about complete my modding of the whole thing.

-walker

I'm goin ahead and building my ferm. cabinet and was lookin into temp. control. Looking into this Ductstat it seem the info in the above post is worng...

40° to 110°

DuctStat Plug Inline Voltage Thermostat

bmarley5780 said:

I'm goin ahead and building my ferm. cabinet and was lookin into temp. control. Looking into this Ductstat it seem the info in the above post is worng...

40° to 110°

DuctStat Plug Inline Voltage Thermostat

Click to expand...

The Home Depot page also lists this as 40° to 110°. The OP had posted the wrong info.

Is 5 amps enough for even a small fridge compressor?

? I have no idea. I cant find any spec sheets online that lists such.

Looks like you would either have to drill a 1/2" hole in the fridge to mount it over, or put the whole thing inside.

Was considering this mod for the ductstat if it uses a thermosistor

http://www.wortomatic.com/articles/Remote-Sensing-DIY-Controller-for-Less-Than-$25

I donno, just thinkin out loud...