HLT HERMS - 4 Control Panel construction

[drut]

HLT HERMS - Control Panel construction:
This panel is designed for no more than 10 Amps - i.e. one 2.4KW kettle element or similar.
The constraints are due to the Temperature Controller internal relay. Thus the mains IN/OUT connector is suitable for 10A maximum. If you need more, you should use a relay or SSR and higher rated switches, cable and connectors (some ideas below).
If you are not absolutely sure of your ability to build and if necessary modify electronics of this sort, please ask someone who can.
Please let me clarify one point about the difference between Simple Temperature Controllers and PID controllers when applied to HLTs. A Simple Temperature Controller can keep the liquor temperature within 0.25C quite easily - it depends on the hysteresis you set. It is ideal for the control of a large mass of liquor and it will result in the minimum heating time because it is 100% on until it reaches the set temperature. A PID controller is overkill in this application - but use one by all means if you have cash to spare.
Please read the "Background and tests" posting to see the actual, measured results obtained with a STC1000 and no stirring. If the HLT is insulated, or if the liquor remains static for a significant time, stratification may occur - however, this will not happen while the HLT HERMS is running.

The switch "HERMS Power" is fitting but not yet used. It allows a second heat exchanger to be brought into service e.g. for brews of 100-200 litre.

Control Panel circuit diagram:

Control Panel front:

Control Panel side with connectors:

Control Panel internal parts and wiring:

The Power Supply for the second pump is not fitted in the pictures for clarity.

The metal case is earthed with an additional earth to the hinged front panel. There are no additional exposed conductive parts, but if yours has any, they need to be electrically bonded to the metal case. Rigid plastic cases (e.g. ABS but not polyethylene) are suitable if mechanically secured e.g. to a wall or brewery frame. Wood is unacceptable as it can become damp or even soaked and as you all know, electricity and water do not mix. Covers, panels and lids etc should be fixed with screws, not push-on or clip-on.
If you use a non-metal case, all fixings and brackets which pass through the casing and are externally exposed must be individually earthed for your, and your children's safety. This further implies that the casing must be rigid - polyethylene, polypropylene, wood etc will deform under pressure and the earth bonding will fail.
The mains and low voltage wiring are separated and secured for safety; if a wire should come loose it will not cause a short between live and LV parts.
(These last two points are covered by the design consideration of "first fault/failure").

The internal mains wiring is 1.0 mm sq apart from the double insulated routes from the 12V/Pump(s) switches to their respective power supplies which is 0.75 mm sq. The 1.0 mm sq wiring used here is high temperature rated and I suggest using 1.25 or 1.5 mm sq if using standard PVC insulated cable.
(Standard PVC 1.0 mm sq is right on its limit at 10A with 4 bunched conductors - ref. IEE Wiring regulations).
For the low voltage wiring, Cat 5E cable is used for convenience, cost and neatness - this should be the stranded type used for patch leads, not single cored structured cabling (it needs flexibility when the door is opened and closed).

Some of the parts used: (not the cheapest sources)
Sensors for test only LM35DT http://uk.rs-online.com/web/search/sear ... R=535-9458
Sensors for test only LM35CAZ http://uk.rs-online.com/web/search/sear ... R=533-5878
Case http://uk.rs-online.com/web/search/sear ... &R=231-970
3 position switch http://uk.rs-online.com/web/search/sear ... R=706-4023
Illuminated switches http://uk.rs-online.com/web/search/sear ... R=456-1694
6-PIN connectors http://uk.rs-online.com/web/search/sear ... R=261-5806
(Strictly the wrong sex, but ok at 12 volts)
Connectors for probes and motors - Maybe DIN Audio or similar (I have a box full of the Lemo ones shown)
Mains IN/OUT http://uk.rs-online.com/web/search/sear ... R=211-1017
12volt 4A PSU http://cgi.ebay.co.uk/12V-4A-LCD-Monito ... 4aa6039836
Temperature controller (HLT) http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0609566283
PID http://cgi.ebay.com/NEW-DUAL-DIGITAL-F- ... 45f9f89046
HLT probe (NTC) http://uk.rs-online.com/web/search/sear ... &R=0461159
PT100 probe http://cgi.ebay.co.uk/Thermocouple-Temp ... 230eb668ca
Plumbing parts - mainly http://www.screwfix.com

Not used, but suitable for operation to 20A:
Mains connectors:
http://cpc.farnell.com/bulgin/px0596-63 ... dp/CN08375
http://cpc.farnell.com/bulgin/px0599/ma ... dp/CN08372
SSR http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... SA:GB:1123
Fitted onto e.g. http://uk.rs-online.com/web/search/sear ... &R=5075194
Please note: Fins vertical in free-flowing air at an ambient of up to 50C, 25A, check thermal de-rating curve.
Adequately scaled heatsinks are vital for safe operation. You could well need an additional fan if the heatsink is mounted inside the case. Fins should always be vertical and in free air - think about it - if you put the heatsink inside a sealed box, the box will get hot and the heatsink hotter.

Safety issues:
Unlike some forum contributors, I have not taken exams for IEE Regs, Part P etc.
Instead, from the early 1980's to the mid 2000's, in conjunction with many other consulting engineers, I was writing parts of these standards and exams, including IEC601, BS5750 and the above. Therefore I know why we draw up specifications - not just the details but the reasoning behind them.
If at all possible, have your completed panel tested by a competent electrical engineer using a calibrated and checked PAT device (Portable Appliance Testing).
Most of the forums posts are light hearted, entertaining and fun, this one is not.
Killing yourself or your kids by ignoring safety or shoddy workmanship is suicide or "manslaughter by gross negligence" - look it up.

 

[46.philh]

When do they go on sale ? :thumb:

 

[retourrbx]

would the main inlet/outlet not need to be hot condition IEC as well?

 

[brougham]

Do you think the HLT controller and NTC would be suitable for a kegerator?

On the cooling output of course. I have a potential for conversion but the existing stat doesn't want to know over 8-10C, it just doesn't have the accuracy

 

[Darcey]

What did you use as the pump speed controller? I am yet to find something that I can mount in a panel.

 

[unclepumble]

For acurate speed control of a pump without burning it out you need something like This. Very easy to wire and set up if you read the manual, & have some electrical savvy.

Some will try to control with a Triac but this is not ideal.

Failing that a balance valve between the suction and delivery side of the pump & a Gate valve on the delivery side above the balance valve works best & is cheap. (that's what I use & I can set and inverter up with my eyes shut, however I don't see the point in spending £100+ when £15 quids worth of valves & Pipework will do the job as well.)

UP

 

[Scorrie]

A good piece of work there, Drut.

Thanks for taking the time to put it all online.

 

[Darcey]

For acurate speed control of a pump without burning it out you need something like This. Very easy to wire and set up if you read the manual, & have some electrical savvy.

Some will try to control with a Triac but this is not ideal.

Failing that a balance valve between the suction and delivery side of the pump & a Gate valve on the delivery side above the balance valve works best & is cheap. (that's what I use & I can set and inverter up with my eyes shut, however I don't see the point in spending £100+ when £15 quids worth of valves & Pipework will do the job as well.)

UP

I suspect you are correct and I will end up with the bypass loop solution I am only using the cheep 12V solar pumps so was looking for a neat alternative before I build the control panel.

 

[Aleman]

I am only using the cheep 12V solar pumps so was looking for a neat alternative before I build the control panel.

Those little 12 pumps can simply be controlled via a voltage controller. Either one of those multi voltage wall warts, or a 'railway speed controller. Personally I use an LED Dimmer from eBay. The chap at Solar project shop recommends voltage control as the way to control them.

A bypass loop works well and gives smoother control . . . particularly at lower flow rater.

 

[Darcey]

Those little 12 pumps can simply be controlled via a voltage controller. Either one of those multi voltage wall warts, or a 'railway speed controller. Personally I use an LED Dimmer from eBay. The chap at Solar project shop recommends voltage control as the way to control them.
A bypass loop works well and gives smoother control . . . particularly at lower flow rater.

A cheap LED dimmer eh? Three way dimmer? for the planned three way pumps. :hmm:

I have a railway controller somewhere that I have seen people using but I want something I can mount in the brewery controls to keep everything together. Peter has advised me that an LED dimmer wouldn't be suitable but then again he is trying to sell me a voltage controller for £15.

 

[Aleman]

There was a discussion on JBK (solar pump voltage Control) about if the LED Dimmer was suitable, as it produces a square wave at 12V . . .but with a variable frequency. . . If the motor produces Back EMF then in theory that can blow the FET output stages in the Dimmer. . . . I've not had that happen yet.

"Some people like to power the pump from a Photovoltaic panel, in which case the manufacturers advise that you ensure your PV panel does not exceed the 14 volts maximum rating for these pumps as this could theoretically damage the control electronics within the pump body. Having said that, I have not seen one damaged in this way in my own prolonged tests with a PV panel generating up to 17V in bright sunlight. Similarly, they do run successfully at voltages lower than the stated 9V if you wish to use voltage to reduce flow rates."

Then Later On

I came across this discussion of my solarproject.co.uk SP20/20 and SP14/10 pumps and how to control flow rates. There are three ways that I have tested:
1/ Use a variable power adaptor: The pumps are incredibly tolerant and will run on 6,9,12 Volts (and more in my tests) There are plenty of cheap switchable regulated plug in adaptors on ebay that will do the job. Go for a minimum output capacity of 1Amp or 1000milliWatts.
2/ For electronic enthusiasts I have successfully tested the 2 metre head version using PWM . I have no reason to believe the 3 and 5 mtr models are any different.
3/ The pumps are quite happy to run against a restriction so add a tap, valve or just squeeze the pipe until you get the flow you want.
I don't know exactly what control electronics are contained in the waterproof resin but they have proved themselves very resilient to all the abuse I have subjected them to. I just had a chap tell me he is running his on 21.5 Volts, which I definitely don't recommend, but it is still running!
Peter http://www.solarproject.co.uk

So as the LED DImmer produces a PWM Square wave there should be no issue with using an LED Dimmer . . .but this was from FEB last year so in further testing things may have changed.

 

[Darcey]

Hmm :hmm: I think its beard scratching time. As the pumps will only be used for a max of one hour at a time I think I may try the LED dimming solution and see what happens. If I end up restricting or using a feedback loop I can always use the dimmers to create a LED light show while sparging. :rofl:

 

[Vossy1]

proper blinged up brewery :rofl:

 

[Morgan]

Nice comprehensive post posting.php?mode=reply&f=13&t=15184#

If you only need 1a to run a 12v pump, why not build a small circuit based on a stir plate controller using an LM317 http://stirstarters.com/instructions.html

Are the PT100 probes compatable with the PID? It didn't mention on the ebay page that PT100 were. Is there any reason to use this particular PID, seems overpriced compared to other models such as the REX-C100.

 

[Vossy1]

Is there any reason to use this particular PID, seems overpriced compared to other models such as the REX-C100.

They are a great price, however they weren't available when a lot of systems were built...I get the feeling they will be getting a lot of attention now though

 

[unclepumble]

The solar Pump is 12V DC therefore a simple potential Divider circuit with a Pot will do the job, (Voltage control as the others have said.

If you want to go over the top you could buy one of These RS are not far from you just behind the Sorting office near the PYRAMID

A Much more sensible option & much cheaper would be This from Maplins, also not very far from you in stockport.

The Light controllers & LED Dimmers are much the same, but if you want to panel mount the Maplins Jobbie is the one I would buy.



UP

 

[Darcey]

Nice one UP! :thumb:

If I mount it properly and it breaks at least it'll still look the part in the pannel
Guest: "What does that do?"
Me: "Ohhh no dont touch that, it controls beer funkology...."

 

[Frisp]

REX-C100

Are these the current dogs danglies for PT100 probes then?

 

[Swift Pint]

REX-C100

Are these the current dogs danglies for PT100 probes then?

By defualt the REX-C100 will only work with K-Type probes, but you can change this by delving deep into the settings. The manual which came with mine didnt explain this, but PJBiker gives a good explaination HERE.

 

[Darcey]

Stupid question but what are the sticky things used to hold the cables down.. I asked in Maplin but the saturday boy wasn't very helpful.
If they are called cable sticky things then I shall be