Boiler Automation Electrical Advice Required

strange-steve · Jul 5, 2016

BREWERS DROOP said:
Spoke with my electrician today,your right 240v is now 220v just like 3 phase 415v to 400v

PeeBee is quite right, nominal voltage was changed from 240V to 230V to comply with Europe but in practice nothing really changed because we are within the +10% allowance. So although voltage is stated as 230V the average actual voltage is still around 240V. The difference in current draw between 220V and 240V for a 5.5kW element is only 2 amps or so and a 25 amp supply should be fine.

BREWERS DROOP · Jul 5, 2016

Taken the plunge and ordered 2 Omron PID with 25a SSR,not sure of the thermocouple type yet any reliable suggestions?

strange-steve · Jul 5, 2016

I'd maybe have overrated the ssr. I run a 16A element via a 40A ssr and it gets pretty damn hot.

Fil · Jul 5, 2016

BREWERS DROOP said:
Taken the plunge and ordered 2 Omron PID with 25a SSR,not sure of the thermocouple type yet any reliable suggestions?

most folk use pt100 probes, best to get a European sourced probe imho i have bought a few chinese ebay bargains some have fallen apart before arriving, others read wide off true and many sold as SS have the probe sheaf in SS but the thread and nut fixings are simple steel prone to rust, which wont be water tight even if fitted.. ..

Inkbird · Jul 12, 2016

HebridesRob said:
Got my PID and SSR off Inkbird, but no heat sink (apparently the warehouse made an error). The K sensor that came with it isn't going to be much use because:
1. I can't find any fittings that will allow me to reduce 1/2" BSP to 1/16" thread.
2. It isn't watertight.
3. the sensor isn't long enough.
So, I've ordered a model with 1/4" thread and 5cm sensor. Inkbird said they'd send me a heat sink, am awaiting delivery (they said they'd send it but haven't confirmed it's been sent ).
So, frustratingly, I can't use the thing properly until I get the heat sink but I've wired it up and used for as long as I dare and seems OK.

Hi,sorry to hear that something missing from the package you got. I do know you ordered on amazon or ebay. Maybe you can send us a message directly on ebay or amazon.We will confirm and give you a solution.

GermLish · Jul 12, 2016

I bought this one on ebay.

Dutch seller (European warranty = UK warranty) and waterproof: http://www.ebay.co.uk/itm/182147398743

JapanBrew · Jul 12, 2016

I always buy a few extra. Since I use the STC units, I fitted mine with those RCA plugs. They're cheap and everyone has a million of those cables around your house. Just chopped them off, little soldering and my units can be moved around and sensors can be washed, sanitized and put away b

HebridesRob · Jul 19, 2016

Inkbird said:
Hi,sorry to hear that something missing from the package you got. I do know you ordered on amazon or ebay. Maybe you can send us a message directly on ebay or amazon.We will confirm and give you a solution.

All done, all fine, thanks!

HebridesRob · Jul 19, 2016

JapanBrew said:
I always buy a few extra. Since I use the STC units, I fitted mine with those RCA plugs. They're cheap and everyone has a million of those cables around your house. Just chopped them off, little soldering and my units can be moved around and sensors can be washed, sanitized and put away b

Good, I was wondering if I could do something like this, using them attached to all that wire is a PITA.

Smileyr8 · Jul 24, 2016

This is what I have come up with.

The first image shows the pump pipework with PT100 temperature sensor at the top

The second image shows the drilling pattern in the base to correspond with the element is in the base of the boiler

The PID, pump etc worked OK barring a few minor niggles, now just need to look at a method of tidying up the wiring.

Any budding H&S advisors or similar look away now.

donchiquon · Aug 26, 2016

A quick question on PID tuning....

Am I right in thinking that once I have tuned the PID to stabilise a mash-sized volume of water with a specify heater power, then I should not vary the heater power?

My set up includes a PID and variable dimmer so I can reduce the power of the element for recirculation. I'm assuming the PID won't like it if I vary the heater power!

I'm planning to set it to strike temp, then adjust it to mash temp once I have doughed in.

Does this all sound sensible?

Hoddy · Aug 26, 2016

Yes once the PID has learned the system and lag times if your vary the power the PID will over/under shoot. It should. If tuned correctly be able to account for variations in the process as it goes. It does mean however that you should test and tweak the best power setting to get the best balance between power and rise time. Too much and it will oscillate allot. Not enough and it'll never get to set point.

Hope that helps.

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Bunglebrewsbeer · Aug 27, 2016

What size element could a PID run? I'm clueless with electrics.

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Fil · Aug 27, 2016

Bunglebrewsbeer said:
What size element could a PID run? I'm clueless with electrics.

Sent from my iPhone using Tapatalk

with pid controllers a SSR is used to switch the element load, the pid controller uses a dc voltage to switch the SSR on and off.

fwiw i use the ebay fortek 25a SSRs with elements upto 3kw.. I have measured the temp of the heatsink attached to my 25A ssr during the heat upto strike and it has surpassed 60C..

the heat is due to the load current and the rapid switching the pid employs.

As a consequence I mount my heatsinks externally to the enclosure as otherwise i would need to consider drilling vent holes and employing fans..

Bunglebrewsbeer · Aug 27, 2016

So could that PID I have operate a 3kw element?

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Fil · Aug 27, 2016

yes just use a suitable ssr and heatsink combo to actually switch the element in theory a 40a or 60a rated ssr should run cooler than the 25a versions i use??

ssrs however can bleed a trickle current when they should be off, i fitted a 240v neon indicator light in my pid controlled element circuit, and noticed it flickering as soon as i gave the control box some juice, I then stoopidly grabbed the dry element it the pot and almost dropped a two storey house out my backside when it was noticably hot, thankfully not burning temps, But an eye opener, so the lesson learnt was dont plug the element/controller combo into the mains with a dry pot!!!! And/Or also fit an isolating switch on at least the live element feed post pid/ssr. a double pole switch to isolate neutral too would be even better..

Bunglebrewsbeer · Aug 27, 2016

Lost!! So what at bear should I run with that element wise?

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donchiquon · Aug 27, 2016

Hoddy said:
Yes once the PID has learned the system and lag times if your vary the power the PID will over/under shoot. It should. If tuned correctly be able to account for variations in the process as it goes. It does mean however that you should test and tweak the best power setting to get the best balance between power and rise time. Too much and it will oscillate allot. Not enough and it'll never get to set point.

Hope that helps.

Perfect - thanks Hoddy.

Good to know I'm on the right track. For now.....!!!!

Smileyr8 · Sep 4, 2016

Smileyr8 said:
now just need to look at a method of tidying up the wiring.

Ok wire tidied here are a few pictures of what I ended up with.

Fil · Sep 5, 2016

ebay and search for 'red airlock grommet' or find one at your lhbs these are a great fit in a compression T and seal a probe such as yours thats not sealed above its SS sheaf.

Boiler Automation Electrical Advice Required

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