Controlling crown urn with STC1000/PID

[takai]

Shit really? My system must be a freak of electronics.. Never overhead once. No additional relays. 1 running my hex and one running the hlt.

Depends on whether your heaters draw their rated spec or not. The heater for my BIAB urn is nominally 2400w/10A, but as you can see in the photo above it actually draws 12.5A or 3000W. I burnt out a heating circuit on a ST1000 by wiring it up with that.

 

[Chris7]

Going over rated spec by 600watts is much higher than I would have expected!

 

[takai]

As would I, but I have noticed its not unheard of with a lot of the products. I borrowed a 20L Crown urn for strike water on Monday that was drawing 11.2A through its '10A' element.

 

[Yob]

Well if you were running it over spec.. Bit different than a blanket statement that they all need an extra relay wired innit..

 

[tavas]

Have run 20+ batches through 40lt Birko and 10A temp controller. No issues so far. (Just realised its not an STC 1000).

Edit: I should note however that I only use the temp controller to control the mash temp temp (usually set for single temp infusion). Once at temp, I switch off the controller and ride out the time. For the boil I disconnect the controller and run the urn straight from the mains.

So I'll qualify my statement above that I've had no issues so far using this method. Cannot vouch for running the boil through it constantly, though I have done this a few times previously with no issues.

 

[Cortez The Killer]

Been running a 2 * STC1000 on my HLT and HERMS for 3+ years without issue

Looking at putting a PID on my HERMS for tighter control

STC1000 allows a 0.3*C swing before it kicks in and will over and under shoot by say 0.8*C with my HERMS arrangement (a $7 kmart kettle with coil in)

Hasn't really bothered me as the swings are consistent from batch to batch but after getting a PID for my electric smoker I'm really impressed at how stable they keep the temps

Cheers

 

[takai]

Well if you were running it over spec.. Bit different than a blanket statement that they all need an extra relay wired innit..

I didnt make the blanket statement so i wont defend that.

But its not about whether you are running it over spec, you dont get a choice in the matter with 99% of heating elements. They are draw as much current as they are built for. However, resistance based heating is a notoriously inaccurate design and so in making a batch of elements they vary all over the shop. In my case as much as 25% extra, although mine is a cheap mass produced Chinese element with bugger all quality control. Many of the larger suppliers such as Crown and Birko will build in overheads into their design so they wont trip circuits. Additionally most electrical items can supply higher than their rated power as an overhead, e.g. your standard 10A powerpoint is perfectly happy pumping 15A through it for reasonable periods.

However, the STC1000 has a very low overhead on the relays inside it. If you see here they are only rated to 10A at 277v:

Even then i would suggest that the rated 10A is pushing the limits of the tiny relay.

So i wouldnt say that your system is a freak, but more that the elements you are using are safely within spec. But do know that most devices out there are out of spec. I have blown up two heating circuits on mine sofar, one from the urn that draws 12.5A and another from a '2400W' oil heater.

 

[Chris7]

Quick question for anyone using the Auberins SYL-2352, I know that it has the 12vdc output for SSR, but is it possible for a 12v mechanical relay to be used at all? Reason I ask is my FIL has some mechanical relays already and it would save some dough. I am guessing it probably won't work though and I will just have to source an SSR.

 

[Camo6]

An ssr off ebay is about $4 delivered give or take. It will handle rapid switching whereas your mechanical relay will likely fail when you need it most. Pretty sure there's an auber pid specifically for mechanical relays but don't quote me. Get an ssr and a heatsink (internal or external) and give yourself some peace of mind.

 

[Chris7]

Cheers, yeh I ended up pulling the trigger a few mins ago haha. I would not have been pleased if we assembled the box only to realise it could not be used. Cheers.

 

[takai]

Cheers, yeh I ended up pulling the trigger a few mins ago haha. I would not have been pleased if we assembled the box only to realise it could not be used. Cheers.

Thats what i did and then realised that the internal heatsink wasnt big enough, hence the big heatsink hanging out the side of the box.