Discuss Brew panel in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

Reaction score
9
I built a panel for brewing and tried it out yesterday, it's is designed to power a 6kw element in a a 70 litre stainless kettle. It ran great doing a 66 degree mash controlled by the PID for 60 minutes, all other controls like pump control, amp and flow meters ran like a dream. When I stepped up to 100 degrees I could smell burning then the trip switch went. The burning was the coil relays (from China) melting. I have two SSR's fitting with each having a heat sink, I fitted a PC cooling fan on the element heat sink. Could this have caused an issue? I have been told to replace the coil relays with 2 pole 40 amp contactor 240V, will this solve my issue. I have attached my wiring diagram does it look right and how would I rewire the new contactors? Any advice would be greatly appreciated!
 

Attachments

  • Brew panel HOW - EletriciansForums.net
    HOW.jpg
    100.8 KB · Views: 81
A quick look at your diagram shows an odd lack of connection between the incoming neutral and the lower of the two terminal strips, is that true?!

If the relays coil is hot/burning most likely it is faulty manufacture, incorrectly labelled (e.g. 110V coil sold as 230V), or simply crap. Replacing them with contactors of known quality should fix things.

If the cause of the over heating is the relay contacts then much the same applies - they were poor quality or very old stock and tarnished/high resistance when first used so able to heat up under load. Generally that sort of thing tends to runaway as heat can further tarnish the contacts, etc.

Finally I guess the enclosure for all of the electrics is kept sensibly cool (i.e. not heated to 70C or so)?
[automerge]1586784983[/automerge]
One final point, that fuse holder illustrated in your diagram looks like the sort you get for automotive electrics and almost certainly is not rated for mains use!

Related to that any fuse used for mains work must be rated for that, i.e. a High Rupture Capacity (HRC) fuse with a ceramic body. Glass one can explode under fault conditions when hundreds or thousands of amps flow and start fires if the holder is not flame proof!
 
Sorry not sure what you are pointing out regarding the neutrals? The diagram I used is from the electric brewery website , that's the fuse holder they sell. I have a digital temperature readout on the panel to read internal temp.
 
Those are USA style connectors, not sure if they would be approved for use in the UK, so I'm guess this all came from America?

But given that, are you quite sure they sent you 230V relays and not 110V ones?

Also what rating is the fuse holder? Did it come with a ceramic fuse?
[automerge]1586786925[/automerge]
For the neutral I would expect a link from pin 2 of the power relay (where the AC neutral comes in) to the lower terminal strip where the neutrals of the relay coils, etc, are joined.
[automerge]1586787448[/automerge]
Given the 6kW rating for the heater that is pretty close to 30A so next typical size of contactor would be 40A like this one:

 
Last edited:
Are the relay coils marked for 220V ac? If so they are then they are unsuitable for use in the UK with its 240V ac mains (forget 230V as a figure). A 220V ac coil will run hot on 240V and eventually overheat and destroy itself.
 
Thanks Marconi yes they say 220v if you are correct that's the answer to my issue. I am going to purchase two 40A DP CONTACTORS to replace the relay coils.
 

Attachments

  • Brew panel IMG_20200412_163832 - EletriciansForums.net
    IMG_20200412_163832.jpg
    74 KB · Views: 64
Running a 220V coil at 253V (upper limit of UK mains) is only 32% more heat and that is not going to melt it in an hour of operation. My suspicion is they are simply not up to the job of switching a 6kW heater, irrespective of what they say on the label!

Some decent 40A contactors should solve the problem.
 
Having had relays of dubious brand melt on you I don't really think very cheap eBay products could be recommended!

These are the same part number as CEF but significantly cheaper (photo seems not to match):
Cheaper but no indication of stock levels or delivery times, etc:
Generally speaking for a 40A contactor anything less than £20 is surprisingly cheap. If you wanted something to just work and last a long time then you probably would go for Schneider and their ones are listed at around £60
[automerge]1586798692[/automerge]
For example:
 
Mark Stewart - could you amplify please what you said in #1:
The burning was the coil relays (from China) melting.

What part(s) of the relay was/were burning? How did the relay fail - the contacts or the coil or both? - some pictures would be welcome for me to pore over.

Chinarelay do a 240V ac version of that coil - interestingly its coil resistance is increased to 8060 Ohms; the 220V ac one has a coil resistance of 6770 Ohms. I wonder why? ;-)
 
Last edited:
Has the relay melted inside, or just the pins going into the base?

Is that a current shunt mounted above the relay base?
 
It certainly looks like a current shunt.

Also there are a surprising number of cable so that relay! I really doubt it is the coil, I think it is the contacts that have burned under a 26A or so load.
 
Mark Stewart: Can we have a photo of the relay bottom and with its cover off?

I agree this relay is not adequately rated to switch and pass 30A for long periods - so you need something with a higher ac resistive load rating - of the order 40A.

I stand by my earlier remarks on the ac voltage (and frequency) rating of the coil.

What is the voltage rating of the heating element ? Perhaps a photo of the data plate?
 
Last edited:
The burn mark is in an odd place, if the contacts were overheating I would almost expect the melting around the pins a bit more rather than the centre. Have you popped the cover off the burnt relay to see inside yet? What wiring diagram are you following as the one you posted has no mention of a current shunt?
 
Like I said before I followed the electric brewery plans. The diagram I uploaded is the plan for the element. Will having a shunt make much difference?
 
I have looked at the electric brewery web site in the USA. The current shunt is there so that at a later date an ammeter or current monitor can be added into the control panel possibly as part of a remote monitoring scheme or data collection for viewing through some brewing software.

No the shunt will not make any difference to your problem which as has been said is the relays have an inadequate specification. Why did you not buy the power and boil relays the electric brewery sell? Anyway you can buy suitable ones in the uk.
 
Last edited:
The shunt won't make any difference to the relay problem.

I still suspect the burning is from the fixed relay contacts coming down there. The moving ones usually have a wire so would not be as hot at the base.

Contactors. You know it makes sense...
 

Reply to Brew panel in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock