Build yourself a cheap digital boiler power regulator

[The-Engineer-That-Brews]

Very nice write up and project..

another option thats a bit simpler is to buy a resistance controlled SSR, unlike the DC controlled SSRs used by pids which need a small dc voltage to turn on, these resistance controlled SSRs use a variable resistor (leky guitar volume knob/500k ohm linear pot) connected over its control terminals which lets you dial up and down the current the SSR allows through its load terminals..

add a ��ã10 volt/amp meter and a box and you have a controller for ��ã15-20..

SSR-40VA 40A 250V Metal Base Resistance Regulator Solid State Relay | eBay

1 5 10 20 50 100 500 K M ohm Linear Logarithmic Mono Stereo Pot Potentiometer st | eBay (500k linear 2w )

ebay links are for examples not recommended sellers, just the 1st with pics found

Regrettably when it comes to SSRs, if it's marked FOTEK then I'm afraid in my experience it is very likely to be a fake. Truth be told I have yet to receive a single SSR from any supplier on Amazon or eBay that wasn't (!)... even the ones where the photo showed a different model, when it arrived it was invariably a knock-off Fotek. So I have now given up with buying SSRs from anywhere but RS or Farnell. They do cost about £10 more, but personally I think it's a small price to pay for peace of mind. It's pretty spot the genuine (top image) from the fakes (lower image)... the give-away is normally that with the genuine parts the recess that the label fits in has a cut-off corner matching the label, whereas the fake has the cut-off corner on the label but just a plain square recess.

see Inferior Counterfeit FOTEK SSR-25 Solid State Relays on the Market - ProtoSupplies

 

[foxbat]

Every single one of the SSRs I've been supplied from those sites has been a fake that uses under-specified triac components.

That'll be the SSRs labelled as 'Fotek' on ebay? Years ago I bought one and was curious as to how come it was so lightweight. Was there anything in it? So I prised the metal base off and the solder joint to the triac underneath was so dry it just snapped right off under almost no pressure! That went straight in the bin and I replaced it with a high quality Opto 22 unit that's still going strong today.

 

[The-Engineer-That-Brews]

That'll be the SSRs labelled as 'Fotek' on ebay? Years ago I bought one and was curious as to how come it was so lightweight. Was there anything in it? So I prised the metal base off and the solder joint to the triac underneath was so dry it just snapped right off under almost no pressure! That went straight in the bin and I replaced it with a high quality Opto 22 unit that's still going strong today.

Sorry - my mistake, I meant to say 'FOTEK' (D'Oh)...

FWIW these ones are what I'm using these days (£13.40 from RS) - they get only slightly warm controlling my Berco; I could probably even get away without using a heatsink

 

[Hanglow]

Thanks for the write up, I have bought one of these to use to control my 2.4kw element which I've found is too powerful once it gets up to boil.

One question I have, is this sort of controller able to be used with AC magnetic drive pumps that we use in homebrewing? I've also recently ordered a pump that does 19 litres per minute which I think would be too much for recirculating the mash which is one of my intentions. It's on/off only with no control

Cheers

 

[The-Engineer-That-Brews]

One question I have, is this sort of controller able to be used with AC magnetic drive pumps that we use in homebrewing?

Regrettably, I think that this kind of controller is probably not going to work well for that type of motor and could damage it. 19 litres per min does sound a bit too fast for recirculating the mash wort. I’m using one of these cheap 12V DC pumps which pumps the wort through my heat exchanger at about 2.2 litres per min...

 

[The-Engineer-That-Brews]

Just for ref, there are two problems with using phase-angle control for an AC motor. The first depends on the type of motor, but if it’s a synchronous AC motor then the speed it runs at depends on the frequency, not the voltage of the mains waveform. The second is that the sharp voltage transitions during switching create a lot of harmonics that do not play nicely with the field windings...

 

[foxbat]

Thanks for the write up, I have bought one of these to use to control my 2.4kw element which I've found is too powerful once it gets up to boil.

One question I have, is this sort of controller able to be used with AC magnetic drive pumps that we use in homebrewing? I've also recently ordered a pump that does 19 litres per minute which I think would be too much for recirculating the mash which is one of my intentions. It's on/off only with no control

Cheers

I'm not sure you'd actually achieve 19 litres per min if pumping against gravity from bottom to top, especially if it's a cheap pump that exaggerates its capabilities. It might be worth trying at full speed before deciding you need to slow it down. Something as simple as a flow restrictor (thin tube) might be enough.

 

[Hanglow]

Thanks for that, I'll probably get a second smaller DC motor for it, or just use a ball valve which from looking at various youtube videos is what a lot of people do

 

[Wynne]

@foxbat Thank you for taking the time and trouble with your original post - a very clear and comprehensive set of instructions. I have now built and tested my own controller, so now to brew...

 

[foxbat]

@foxbat Thank you for taking the time and trouble with your original post - a very clear and comprehensive set of instructions. I have now built and tested my own controller, so now to brew...

You're welcome. I find the ideal setting is between 58 and 65 during the boil which seems to equate to around 1.5 to 1.6kW.

 

[The-Engineer-That-Brews]

Thanks for that, I'll probably get a second smaller DC motor for it, or just use a ball valve which from looking at various youtube videos is what a lot of people do

I reckon a nice way to control the flow rate would be use a couple to tee pieces to connect your ball valve as a bypass to the pump, as shown below.
Doing it like this has the advantage that you can control the flow rate through the mash without labouring the pump...

When the valve is closed, you get full flow rate through the tank; but the more you open the valve, the more of the flow goes straight back round to the pump, bypassing the tank.

It's a bit like controlling the speed of your car by using the gears instead of driving with the handbrake half on...

 

[The-Engineer-That-Brews]

pumping against gravity from bottom to top

I see what you mean, but in fact by taking the input to the pump from the bottom of the tank you get the positive head from the height of the tank so it all balances out :-)

 

[underpressure]

Hi Foxbat @foxbat

I have come across this thread which is very helpful, i'm trying to tame a volcanic boil on my burco boiler. I was wondering if you could help me with some questions about the components and wiring?

What size is the cable gland?
What is the spec of the black cable?
I can't really see from the photo how the 3 way boxes are wired so you have any instructions please?
When you say that 2 & 3 on controller are commoned is that standard for the Scr or would I need to do that myself?

Thank in advance

Mike

 

[foxbat]

Hi Foxbat @foxbat

I have come across this thread which is very helpful, i'm trying to tame a volcanic boil on my burco boiler. I was wondering if you could help me with some questions about the components and wiring?

What size is the cable gland?

Mine is M16x1.5 but select your cable first then a gland that will fit its external diameter.

What is the spec of the black cable?

Unfortunately I can't remember. Have a look at the table here and select a core diameter that covers your planned wattage with plenty of headroom. Keep the cable short - mine is only about 50cm.

I can't really see from the photo how the 3 way boxes are wired so you have any instructions please?

Do you mean the little grey boxes close to the cable gland? If so then they are just Wago cable connectors (like these). They're a convenient way to join multiple cables without screws or soldering.

When you say that 2 & 3 on controller are commoned is that standard for the Scr or would I need to do that myself?

I've only ever seen one of these (mine) so I couldn't say what's going on inside any others. You'll have to have a look inside yours.

 

[underpressure]

Do you mean the little grey boxes close to the cable gland? If so then they are just Wago cable connectors (like these). They're a convenient way to join multiple cables without screws or soldering.

Great thanks for all the info, I was looking for instructions on how to wire them up as i couldnt see from the photos. Thanks in advance.

 

[stripeyjoe]

Would this work to control the power to the element? It’s not a huge amount more than all the bits required for @foxbat‘s regulator...
https://www.ebay.co.uk/itm/UK-AC-22...-/224370896728?_trksid=p2349624.m46890.l49286

 

[foxbat]

Would this work to control the power to the element? It’s not a huge amount more than all the bits required for @foxbat‘s regulator...
https://www.ebay.co.uk/itm/UK-AC-22...-/224370896728?_trksid=p2349624.m46890.l49286

It looks like it probably will but given the total lack of specifications and having seen the Chinese approach to electrical safety I'd be taking it apart first to check how it works and also whether they've bothered to connect up the earth pins.

 

[The-Engineer-That-Brews]

Would this work to control the power to the element? It’s not a huge amount more than all the bits required for @foxbat‘s regulator...
https://www.ebay.co.uk/itm/UK-AC-22...-/224370896728?_trksid=p2349624.m46890.l49286

My take on the spec is that it's rated at 2kW (220V x rated current 9A), but may not actually catch fire until 18A

 

[The-Engineer-That-Brews]

Just out of interest I've switched my own temperature controller setup over to a WiFi setup with a web interface. Means I can monitor it remotely, and also lets me add a few more bells and whistles than could for on a 4x40 LCD display.

 

[bobukbrewer]

for £9 try this
https://www.amazon.co.uk/ARCELI-Ele...words=Voltage+Regulator&qid=1620634597&sr=8-5