Using the STC-1000 for Small Batch Automated System

[Derek1985]

I am in the planning stages of a micro-mini Countertop Brutus build (for my 1 gallon batches) and would like to use an STC-1000 I already own in place of the PID.

I figure the small heat source (stubby 1500W element) I plan to use, coupled with a relatively small heat sink (max 3 gal of water) will render it relatively accurate.

Any thoughts or suggestions?

 

[day_trippr]

What are you going to use for temperature probes?
I suspect the plastic one that comes with the unit isn't going to work...

Cheers!

 

[Derek1985]

What are you going to use for temperature probes?
I suspect the plastic one that comes with the unit isn't going to work...

Cheers!

Could I use a thermowell?

 

[55x11]

I am in the planning stages of a micro-mini Countertop Brutus build (for my 1 gallon batches) and would like to use an STC-1000 I already own in place of the PID.

I figure the small heat source (stubby 1500W element) I plan to use, coupled with a relatively small heat sink (max 3 gal of water) will render it relatively accurate.

Any thoughts or suggestions?

Sorry - MISREAD the topic. I thought you wanted it for fermentation.

 

[day_trippr]

fwiw, the OP is building a micro brew structure to make wort...

No idea about thermowells - it's not exactly a standard size probe and I don't know how well it could be thermal-coupled to the metal well.
And then there's the temperature exposure - are you going to use this to manage a HLT?
What's the range for which the probe is rated?

Cheers!

 

[Derek1985]

Still in the planning stages. More than likely i'll buy a PID and an RTD probe. Just wanted to send out feelers.

I've heard of people using the STC-1000 with mixed results.

 

[Bellybuster]

I'm surprised you haven't got any negatives yet.
The stc1000 will continue with full power heat until the set point is reached. That will leave you with a hot element in a small amount of wort with little thermal mass. The small amount is a negative not a positive. Your temps will have huge swings.
PID is the way

 

[alphaomega]

I'm surprised you haven't got any negatives yet.
The stc1000 will continue with full power heat until the set point is reached. That will leave you with a hot element in a small amount of wort with little thermal mass. The small amount is a negative not a positive. Your temps will have huge swings.
PID is the way

No it won't. There is neglible mass in the element and it takes a LOT of energy to raise the temperature of 3 gallons of water. The limitations will be the accuracy of the temperature and the 0.3C (if I remember correctly) minimum hysteresis of the STC.
Neither of which is a major problem IMHO.
As long as you don't have issues with scorching, an STC will do just fine.

 

[AnOldUR]

I figure the small heat source (stubby 1500W element) . . .

Isn't the STC rated for 10amps.


edit to say:
My ugly junk that I've used for years is a Johnson A419 (probe in thermowell) and a router speed control to adjust heat intensity of a 1650W element. Works fine, but I've been accumulating the stuff for a new control.

 

[Derek1985]

I'm surprised you haven't got any negatives yet.

The stc1000 will continue with full power heat until the set point is reached. That will leave you with a hot element in a small amount of wort with little thermal mass. The small amount is a negative not a positive. Your temps will have huge swings.

PID is the way

I understand it to be the opposite. A small source connected to a large sink will result in massive swings.

I could be wrong though. I was under the impression that a small sink attached to a small source would provide relatively stable and reasonably accurate set point manipulation.

 

[alphaomega]

Isn't the STC rated for 10amps.

The stc's I know (the A400_P hw) are rated at 10A @ 230VAC and 15A @ 115VAC.

I understand it to be the opposite. A small source connected to a large sink will result in massive swings.

For thermostat control, a large source and small sink will be likely to cause over/undershoots, but it depends on the system.

 

[AnOldUR]

The stc's I know (the A400_P hw) are rated at 10A @ 230VAC and 15A @ 115VAC.

Can you provide a link to that? I hope that someone with more electrical knowledge will join in, but as far as I know it's a 10 amp rating, regardless of the voltage up to 250VAC. The power relays inside the STC-1000 are rated at 15A/125VAC, but that doesn't mean the traces and other components will handle 15 amps.

 

[Derek1985]

I figure the system will be as follows:

BK with 1500W stubby screw in element. I'll use this to heat my mash water which will be pumped via cheapie tan 12vdc pump to my 2 gallon Coleman stacker MLT. recirculating will then happen between BK and MLT with a modified STC controlling. That's how I envision is at least.

 

[alphaomega]

Can you provide a link to that? I hope that someone with more electrical knowledge will join in, but as far as I know it's a 10 amp rating, regardless of the voltage up to 250VAC. The power relays inside the STC-1000 are rated at 15A/125VAC, but that doesn't mean the traces and other components will handle 15 amps.

Edit: oh... I read the entire post now...
Well, no it doesn't. But the stc is a prime piece of chinese engineering. If you want certifications, you are looking in the wrong place.
If the traces handle 10A at 250VAC, the heat generated by 15A at 125VAC would be less (assuming resistive loss from the traces).

 

[Derek1985]

You could remove the stock relay from the board and wire in one with higher rating and a heat sink.

 

[AnOldUR]

You could remove the stock relay from the board and wire in one with higher rating and a heat sink.

So, as a kid, it never bothered you the the Six Million Dollar Man could run 60MPH without ripping the rest of his body apart, even though only his legs and one arm were bionic?

 

[Derek1985]

So, as a kid, it never bothered you the the Six Million Dollar Man could run 60MPH without ripping the rest of his body apart, even though only his legs and one arm were bionic?

Let me back up:

Let's play this conservatively and say the switching relay for the heating portion of the STC is rated for 10A. It would not be able to pass the heating element current directly. I recall a blog post by an Albany, NY area native concerning his use of the STC for his HLT in a system similar to the Countertop Brutus.

An SSR/heat sink combo would require if I remember correctly somewhere between 3-32VDC. If you de-solder the internal relay and connect the internal 10V transformer to a SSR/heat sink, you could pass the current of the heating element with no issues. This would mean maybe $7 in parts.

 

[Derek1985]

So, as a kid, it never bothered you the the Six Million Dollar Man could run 60MPH without ripping the rest of his body apart, even though only his legs and one arm were bionic?

Who is the Six Million Dollar Man? :cross:

(I'm not old enough to remember watching it, but not young enough to forget the awesomeness that is Steve Austin)

 

[alphaomega]

Let me back up:

Let's play this conservatively and say the switching relay for the heating portion of the STC is rated for 10A. It would not be able to pass the heating element current directly. I recall a blog post by an Albany, NY area native concerning his use of the STC for his HLT in a system similar to the Countertop Brutus.

An SSR/heat sink combo would require if I remember correctly somewhere between 3-32VDC. If you de-solder the internal relay and connect the internal 10V transformer to a SSR/heat sink, you could pass the current of the heating element with no issues. This would mean maybe $7 in parts.

https://github.com/matsstaff/stc1000p/wiki/1.5.2-Solid-state-relay

But the stc won't have a problem with a 1.5kW heater.