Control Panel Wiring Check

Hello all. Long time reader, first time poster. First and foremost I want to thank everyone on on HomeBrewTalk for your valuable contributions and information. After reading through countless posts I was able to put together my first all grain HERMS system and brewed my first batch last week! Couldn't have done it without all the great info on these boards.

I am attempting to put together a simple control panel that will display temp readings from my 3 Auber RTD sensors as well as provide on/off switching for my single pump and my induction cooktop. I am very new to electrical wiring and have attempted to model my layout based on the great info provided over on TheElectricBrewery.com (mine is obviously much more simplified, requiring manual controls and only having temp displays, not PIDs)

I'm hoping someone more knowledgeable could look at my wiring diagram to see if it makes sense before I start ordering parts. Thanks.

View attachment WiringDiagram.pdf

 

I figured a description of my system would be helpful.

We have a two tier hybrid herms system with a 15 gallon SS boil kettle, 10 gallon igloo mashtun and 10 gallon SS HLT. I say hybrid because the boil kettle is propane fired but the HLT is heated with a portable induction cooktop. We use the boil kettle to initially heat all water because the induction cooktop is a little slow. However the cooktop does a fantastic job of maintaining/modulating the HLT temps. We use a single pump for all transfers except that we gravity feed into the boil kettle during mash out and sparge.

 

At first glance it looks like your wiring diagram should work. It's a 'macro' look so it's tough to tell what runs to where specifically (terminals etc) but you have the right power going to the right devices.

Your 120V heater light - the way you have it wired now, it will be on all the time. You probably want th eblack line running to the output of the relay, not the input to the switch.

 

Thanks BNB. Great catch on the heater power light. I'll swap the wires for that. Also considering going with illuminated push-button switches to save on space instead of having a separate switch and light. That will change things a bit but the concept remains the same (I think).

Two questions though. Do I need to run a ground wire from my AC/DC converter? Would it be possible to hack apart an old 'wall wart' power supply that meets the specs and use that -it does the same thing, correct? I just have a whole box of old power supplies in the garage and would like to reuse something rather than buying new...

 

Take a look at my build - I did the same things, illuminated push buttons and a wall wart. With the wall wart, mine only had 2 prongs so there was no place to run ground.

 

Thanks, will check out your build.

Does any have experience with these cheap-o RTD meters from ebay? About to pull the trigger on them...

http://www.ebay.com/itm/DC-Digital-...819?pt=LH_DefaultDomain_2&hash=item3a7a532a3b

 

I haven't seen them used... Wouldn't even know which of the wires goes where for the RTD - b/B/A?

 

If you want a cheap panel mount thermometer, check out these or similar, they use battery power:
http://www.amazon.com/Digital-Thermometer-Display-Fridges-Freezers/dp/B008HYCHFW/ref=pd_sbs_indust_1

I don't have any DC power in my panel so the 24vDC would require an extra transformer.

 

Thanks for the suggestion jCOS. Unfortunately looks like most of those only go up to ~158 degrees. I need something that goes higher and can be placed into the liquid. This is why I am going with the RTD sensors that come with the attached thermowell and xlr connectors from Auberins.com

 

I haven't used the cheap displays but one of the descriptions says 110 C max temp.

By the time you add a $40 deluxe RTD sensor, it isn't exactly a cheap thermometer any more. You might consider mounting an analog or digital thermo directly to the kettle or getting an inexpensive PID ($20-30) for both temp readout and temp control.