Simple Electrical Q - Yes, I realize I am clueless

[Tranesblues]

Hi Guys,

This will probably prove to be a really simple answer here. I admit fully to being a complete dunce on circuits. Having said that, I would like to try and convert my SOFC to keep temps on my brew WARMER instead of COLDER. I know, I know, Why? Im not really even gonna go into detail on that. It's not important. I just need to keep temps warmer now that it is winter. I followed the standard setup for the chiller (which by the way, worked fabulously this summer in Mississippi where temps hit 90-100 regularly) and I am using the standard Honeywell, non-digital, non-programmable thermostat to hook it up. My issues is that the plans for the chiller are designed to have the stat turn on and off at the low temp. I need to set it to RAISE the temp. I suspect that has to do with the way the wires are set up, but as stated, I am a dunce. I am posting a pic of the way it is setup now. If the simple answer is no, is there a thermostat I could upgrade to to do this? Thanks for the help.

 

[Jupapabear]

I do not know how to achieve what you are asking using what you have, but a cheap STC-1000 is what I use on my fermentation chamber. There is plenty of knowledge here on HBT about wiring them up, and usually you can get them shipped with amazon prime. Hope that gets you going in the right direction.

 

[day_trippr]

A model number might be helpful...

Cheers!

 

[Tranesblues]

This one is the absolute bottom of the Honeywell barrell - CT31A. Nothing in the paperwork makes it clear to me. Thanks.

 

[ajdelange]

I have no idea how you have things set up and I don't know what an SOFC is, but what you have there is a garden variety thermostat. The way these work is that you connect 24VAC hot to the R terminal. If the thermostat senses temperature below the set point it calls for heat by connecting the 24 VAC to the W terminal. If it senses temperature above the set point it connects 24 VAC to the Y terminal. If the fan mode is in auto it connects the G terminal to 24 V whenever there is a call for either heat or cooling. The fan terminal (G) can also be set on continuously. Thus in normal use the Y wire goes to the compressor on your A/C and the W wire to your furnace.

Apparently you are using the fan in AUTO mode and connecting G to whatever you are using to make cold (through a relay, presumably). To use this thermostat for heating and cooling connect Y to a relay which turns on the cooler or opens a cold water valve or fire up an air conditioner or whatever. Connect another relay to W and use it to energize a heater, open a hot water valve etc. If there is a fan involved G can still be used to control it. If there are separate fans they can be wired to W and Y.

If you tell me what the heat and cooling sources are perhaps I can be more specific.

 

[Tranesblues]

In this case the SOFC is a diy chamber usually used to chill wort. Its a rudimentary setup overall. 9v adapter hooked to cpu fan and thermostat. When the temp in the 'wort chamber' warms up to the setting on the thermostat, the fan turns on exchanging air from the wort chamber with another chamber filled with ice. I would like to have the exact same setup except use a heat source and have the stat turn on to heat the wort chamber up in the same manner. I use the cooling setup in the summer to keep temps low and would like to try the other setup this winter to keep the wort warmer than it will get in freezing temps. As it is setup now the stat can only cool the chamber (fan kicks on the lower temp). I would like it to do the opposite (fan runs to raise temp). Just not sure how to adjust the wires. Thanks.

 

[physics911]

I recommend the Lerway STC-1000.
I have one and love it. I'm fixin' to order a couple more. Yes you have to wire it yourself (20 minutes), and it only displays in metric (everyone should be using metric anyway), but it is a fraction the cost of a Johnson Controls, holds a steady temperature, and has both cooling and heating outputs.

 

[Tranesblues]

Can I use that with the son of a fermentation chiller? I thought it was only for use with chest freezer or devices with a compressor.

 

[physics911]

It's just a relay connected to a temp probe with a bit of logic; you can use it with anything which plugs into a standard outlet. You could have your kitchen blender come on when the room temp hits 68 degrees if you want. Not sure anyone would want to do that, just illustrating that it is nothing but a simple logic circuit which turns off and on an electrical switch.

The reason we use them specifically for freezers is a freezer, well freezes, and we don't want that. So instead of rigging a bunch of stuff, you simply use an external controller that turns the power off and on as needed to maintain the temp you set.

 

[ajdelange]

In this case the SOFC is a diy chamber usually used to chill wort. Its a rudimentary setup overall. 9v adapter hooked to cpu fan and thermostat. When the temp in the 'wort chamber' warms up to the setting on the thermostat, the fan turns on exchanging air from the wort chamber with another chamber filled with ice. I would like to have the exact same setup except use a heat source and have the stat turn on to heat the wort chamber up in the same manner. I use the cooling setup in the summer to keep temps low and would like to try the other setup this winter to keep the wort warmer than it will get in freezing temps. As it is setup now the stat can only cool the chamber (fan kicks on the lower temp). I would like it to do the opposite (fan runs to raise temp). Just not sure how to adjust the wires. Thanks.

OK. That's pretty simple. Remove the block of ice and install a small light bulb in the chamber where the ice sits. Wire a 9 V relay's coil between the W terminal on the thermostat and the wall wart wire that doesn't go to the R terminal. Wire the light bulb to 120V through the relay's normally open contacts. Switch the thermostat to HEAT mode. When the thermostat senses temperature below the set point it will start the fan and turn on the light bulb.

You could probably make it work adequately without any wiring addition by putting a small light bulb which is on all the time (no relay) in the ice chamber. The bulb will warm the air in that chamber. How much depends on the size of the bulb and you'll have to experiment with that. All you have to do with the thermostat in this configuration is switch it to HEAT. When the controlled chamber gets cold the thermostat will then turn the fan on.

 

[Tranesblues]

Awesome. Thanks yall.

 

[ajdelange]

A model number might be helpful...

It certainly doesn't hurt to know the model number but I'd just like to point out that these terminal labels are standard and would apply equally well to hundreds of other thermostats.

 

[day_trippr]

fwiw, I just wanted to know if that model was even capable of COLD regulation.
The OP didn't show the front of the unit, it's not uncommon for such cheap thermostats to share plastics across multiple models, and I've seen similar Honeywell units that can only manage a low voltage heating function (indeed, I used one on a cold-season ferm cabinet)...

Cheers!

 

[Tranesblues]

I might not understand the verbage here but I definitely have been using it to cool. I should say though that the setup for this doesn't necessarily use the stat in the way intended.

 

[ajdelange]

fwiw, I just wanted to know if that model was even capable of COLD regulation.
The OP didn't show the front of the unit, it's not uncommon for such cheap thermostats to share plastics across multiple models, and I've seen similar Honeywell units that can only manage a low voltage heating function (indeed, I used one on a cold-season ferm cabinet)...

It's been a long time since I've seen one that is not capable of handling cooling as well as heating. Obviously COOL as one of the options on the mode selector (front) is an indication that handling a cooling load is possible. The presence of the Y terminal (goes to the A/C compressor contactor) tells you the same thing from the rear.

Note that if the thermostat is designed to control a heat pump Y is hot for either heating or cooling demand with O(range) also hot for cooling and Blue hot for heating. Obviously this is not the case here as those terminals are not installed on the PC board. They would be for other models based on this board.

 

[day_trippr]

As I said, the OP never showed the front so the modes were unknown, I have a very similar Honeywell unit that can only handle one mode (yet still has all the internal bosses and markings for a much more capable thermostat) and 43 years as an EE has taught me never to assume anything...

Especially anything shown on HBT...

Cheers!

 

[ajdelange]

As I said, the OP never showed the front so the modes were unknown,

This is starting to get a little silly but by your reasoning, we could be certain that this thermostat is capable of cooling because that's how OP is using it but not certain that it can be used for heating because we don't accept that a terminal complete with screw installed (W) is indicative that the associated function is available.

I have a very similar Honeywell unit that can only handle one mode (yet still has all the internal bosses and markings for a much more capable thermostat)

It has a complete Y terminal (like the Y terminal in the photo - not like the O or VT1 'terminals' and it won't handle cooling?

...and 43 years as an EE has taught me never to assume anything...

If the evidence is strong, as it is in this case, we can 'trust but verify'. 43 yrs as an EE taught me that common sense will take you a long way. I would assume from the picture that this thermostat, based on complete Y and W terminals is capable of heating and cooling (but not with a heat pump, as the O and B terminals are missing). I would assume the VT1, VT2 and VT3 functions, whatever they are, are not available, based on incomplete terminals. But I would verify that the thermostat works with a continuity checker or VM before installing it.

Especially anything shown on HBT...

You think maybe he photoshopped the pic?

 

[day_trippr]

Dude, I don't know wtf your problem is or what point you're attempting to make, but vaya con Dios, I'm outta here...

Cheers!

 

[ajdelange]

I guess the main points are
1. Thermostats are made by many manufacturers and are intended to be used with a diversity of heating and cooling equipment also made by many manufacturers.
2. In order to simplify interconnection there are standard wire colors used for various functions and standard designations for the terminals.
3. Manufacturers often save production costs by using the same PC board in a variety of models but do not fully populate the boards except in the models that have all the functions.
4. If one sees a PC board with some functions populated but not others he is pretty safe in assuming that the populated functions are available and the unpopulated ones are not. The terminals available are a powerful clue as to what functions are populated. For example if W, Y, O and G terminals are present we can assume that the thermostat will control a heat pump with reversing valve energized during the cooling cycle or furnace and A/C. If only W, Y, and G are present we assume that a furnace and A/C can be controlled but not a heat pump.
5. Brewers can put these thermostats, though intended for home HVAC, to good use in the brewery, if they understand how they work.

As I understand this I don't have a problem with it.

If it isn't very clear to you from the original post that this unit is capable of cooling then you have a problem. The fact that you spent 43 yrs as an EE gives me an idea as to your age. Gentlemen of such seniority as we sometimes have difficulty with things we once found simple. Welcome to the club. An MD I chatted with on Christmas day says that flavenoids from cocoa beans can help. I'm going to try that.