Keg King MkII Temp Controller

[AaronL89]

So I've got problem with my temp controller...

Both the heating and cooling elements turn on at the same time resulting in my brew being a chilly 5 degrees. I usually have it set at 19.5 degrees.

The cooling element is a brand new fridge and the heating element is a heat cable.

The temperature probe is taped on the side of my FV, and I've insulated it with foam.

This is my second Keg King unit that has had this problem.

I've been emailing Keg King and have been told that this problem is impossible.

Has anyone else had this problem occur, and if so, how can it be fixed?

 

[Belgrave Brewer]

Following.

I'm just about to buy 2 temp controllers and was thinking of going with these units. If there's a better option, I'd like to know.

 

[Zorco]

So I've got problem with my temp controller...

Both the heating and cooling elements turn on at the same time resulting in my brew being a chilly 5 degrees. I usually have it set at 19.5 degrees.

The cooling element is a brand new fridge and the heating element is a heat cable.

The temperature probe is taped on the side of my FV, and I've insulated it with foam.

This is my second Keg King unit that has had this problem.

I've been emailing Keg King and have been told that this problem is impossible.

Has anyone else had this problem occur, and if so, how can it be fixed?
Has anyone else had this problem occur?

That's not impossible.

The active may be bridged in the controller. Manufacturing error.

Post a photo and let us see your kit.

Also, power connections from controller to fridge / heater should be reviewed.

Again, a pic of your installed equipment so we can see cable connections.

A first response measure would be to widen the deadband in the controller (assume STC1000 aren't they) and remove the heater element from your system for now. Ferment temp accuracy will be decreased but as long as overshoot is kept within the deadband then heat function (possibly effecting a cooling process - diverging positive feedback closed loop process response) will be avoided.

Min cooling temp seems like it is controlled by fridge thermostat (Primary temperature controller).

Another logical possibility is that you have not installed your controller on the fridge you're aiming to control. [emoji12]

 

[AaronL89]

That's not impossible.

The active may be bridged in the controller. Manufacturing error.

Post a photo and let us see your kit.

Also, power connections from controller to fridge / heater should be reviewed.

Again, a pic of your installed equipment so we can see cable connections.

A first response measure would be to widen the deadband in the controller (assume STC1000 aren't they) and remove the heater element from your system for now. Ferment temp accuracy will be decreased but as long as overshoot is kept within the deadband then heat function (possibly effecting a cooling process - diverging open loop process response) will be avoided.

I've got no idea how to post images here, but I've uploaded some pics to Google Drive

I've substituted the heat cable for a lamp to show both elements working at the same time.

I'm not very savvy when it comes to electronics so I would have no idea how to remove the heater element from the system!

 

[Zorco]

I've got no idea how to post images here, but I've uploaded some pics to Google Drive

I've substituted the heat cable for a lamp to show both elements working at the same time.

I'm not very savvy when it comes to electronics so I would have no idea how to remove the heater element from the system!

Oh, to say differently... pop your heaters and lamps in the cupboard. Don't include them for now. Fridge only.

 

[Zorco]

Excellent video mate.

 

[AaronL89]

Oh, to say differently... pop your heaters and lamps in the cupboard. Don't include them for now. Fridge only.

OK, I've unplugged the heat cable and now only the fridge is connected to the controller.

The controller is displaying that the heat element is active, but the fridge is still running as well.

 

[Zorco]

Alright,

It seems likely the controller is maloperating. My first line of inspection is to check the active from the controller module is connected to BOTH the cooling and heating sockets. (Inside that black enclosure)

How comfortable are you with opening the Keg King controller encolsure (ISOLATED, disconnected, zero power)? If you're in North West Brisbane, I haven't had my first beer yet so could look for you, but more than happy to talk you through it (with beers).

If you prefer not to, no sweat mate. You have compiled enough evidence to claim warranty against keg king!

Well done indeed.


If Keg King refuse to look into it then post it up to me, I'm an Electrical Engineer and can make a formal assessment for you. Who knows, if this is your second then there may be a batch problem.

 

[AaronL89]

Alright,

It seems likely the controller is maloperating. My first line of inspection is to check the active from the controller module is connected to BOTH the cooling and heating sockets. (Inside that black enclosure)

How comfortable are you with opening the Keg King controller encolsure (ISOLATED, disconnected, zero power)? If you're in North West Brisbane, I haven't had my first beer yet so could look for you, but more than happy to talk you through it (with beers).

If you prefer not to, no sweat mate. You have compiled enough evidence to claim against keg king!

Well done indeed.


If Keg King refuse to look into it then post it up to me, I'm an Electrical Engineer and can make a formal assessment for you. Who knows, if this is your second then there may be a batch problem.

I've opened up the box, hopefully you can see what I've posted.

 

[Zorco]

I've opened up the box, hopefully you can see what I've posted.

IMG20161105140227.jpg

Warning! Dangerous Voltages inside Aaron.

CONFIRM YOU HAVE DISCONNECTED FROM THE WALL AND ISOLATED. SEND A PHOTO OF THE WHOLE CONTROLLER ON YOUR DINING ROOM TABLE OR SOMETHING WITH THE WHOLE CABLE IN VIEW.

 

[Zorco]

When I'm sure you're safe, we can proceed.

 

[AaronL89]

Warning! Dangerous Voltages inside Aaron.

CONFIRM YOU HAVE DISCONNECTED FROM THE WALL AND ISOLATED. SEND A PHOTO OF THE WHOLE CONTROLLER ON YOUR DINING ROOM TABLE OR SOMETHING WITH THE WHOLE CABLE IN VIEW.

Everything was unplugged. After I took the pic I closed the box and put the screws back on. I didn't touch anything on the inside.

Sadly I have to leave home now so I can't do anything else right now.

Plus I'm not really comfortable doing anything else to the controller.

 

[Zorco]

OK, safety is #1 priority.


Also, it isn't an STC 1000, so my suggestion about the deadband may not be possible.

We will look a bit further for something definitive, but in any case, I don't think you should use it again until Keg King replace.

 

[Zorco]

Everything was unplugged. After I took the pic I closed the box and put the screws back on. I didn't touch anything on the inside.

Sadly I have to leave home now so I can't do anything else right now.

Plus I'm not really comfortable doing anything else to the controller.

That's good. Electricity isn't a game.

For your convo with Keg King, I've marked up your photo which you might use.

Attached Review.png.

My best estimate from what you've shown is:

(a): The wiring is fine and controller is maloperating by latching both relays and energising both cooling and heating
( B): The wiring is not quite right and the cooling and heating outputs from the controller are paralleled causing both cooling and heating sockets to power up.

In both cases this will cause diverging open loop control outside of the deadband of the controller and the limit will be your fridge's thermostat.


Leave it there.

Good luck mate. I'm sure you have plenty of material to go back to Keg King with and feel free to give me a shout if I can help.

 

[AaronL89]

That's good. Electricity isn't a game.

For your convo with Keg King, I've marked up your photo which you might use.

Attached Review.png.

My best estimate from what you've shown is:

(a): The wiring is fine and controller is maloperating by latching both relays and energising both cooling and heating
( B): The wiring is not quite right and the cooling and heating outputs from the controller are paralleled causing both cooling and heating sockets to power up.

In both cases this will cause diverging open loop control outside of the deadband of the controller and the limit will be your fridge's thermostat.


Leave it there.

Good luck mate. I'm sure you have plenty of material to go back to Keg King with and feel free to give me a shout if I can help.

Thanks for all your help mate! I definitely owe you a few beers!

 

[Zorco]

I should qualify to the viewers out there, that if Aaron had used a 2400W heater say, then that would dominate the fridge's output and the divergence would be in the heating direction.This would potentially be a fire risk and I stand by my comment that Aaron is not to use this controller until it is investigated and troubleshooted.

Edit: Correction. This is technically closed loop control with the probe as the feedback - Therefore an unintended positive feedback loop, but quite clearly a closed loop.

Now, time for that beer

 

[Zorco]

Thanks for all your help mate! I definitely owe you a few beers!

You're welcome.

 

[DU99]

manual

 

[Zorco]

I've overlayed the pinout onto the image and had a look. See attached Review 2.

The heat / cool sides of the enclosure were based on the keg king site came from the image I've attached. Rotated it so it aligns with Aaron's picture.

This suggests the heat and cool are wired back to front, but doesn't explain why both energise as per Aaron's situation.

I just reviewed Aaron's video and he points to the fridge socket in the location matching the photo I attached. So that's OK.

 

[Zorco]

It is starting to look like it has been wired back to front.

Aaron,

Give that a try mate. Plug your fridge plug into the heat output of the controller and DON't connect your heater. Use your lamp in the cool output of the controller. Both being energised is the real problem though.


All a bit strange..... Geeze, I've got stuck on this one haven't I. Off to the pool