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Need 13Amp variac device to 'modulate' a water boiler.

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paulca:
I have previously been using a cheap Chinese variac(?) PCB claiming 40A (lol).  However, after the wire clamps melted and I soldered them on instead, I still don't trust it. I decided I want to upgrade it to be far less janky.

Has anyone seen a reasonably priced high power dimmer?

I'm okay with AliExpress et. al.  As long as there is evidence the thing won't melt at 13Amps for an hour doing a boil and will tolerate another hour at 30% output without melting.

My next home brew beer is depending on this!  Help me make beer!

amyk:
"PWM" over a very long timescale using a suitable relay/contactor may be much better than trying to modulate the current. Water has a lot of thermal mass.

tom66:
Yes, I am wondering why you are using a variac when nearly every thermal regulation system - even the electric shower in my mum's house - just uses slow PWM (1Hz) to control the water temperature despite flow rates being reasonably high.  It will also be a lot more efficient than trying to do it any other way.

radar_macgyver:
Use a solid-state relay (avoid the cheap Fostek fake ones that are popular on AE/Ebay - a Crydom D2425 is about $50) with a reasonable heatsink. Drive it with a PID process controller (like the Omega CN32i) with a food-grade RTD sensor to measure the mash temperature. This is a common homebrewers' setup. If you're buying a new process controller, look for one with voltage outputs that can directly drive an SSR, this simplifies the design and lets you do PWM. Controllers are also available with relay outputs, these won't work for PWM and only do on/off.

paulca:
Interesting.  To be clear though, I am not aiming at holding a temperature.  I am interested in controlling the amount of latent heat of evaporation of water at boiling point.  With the 3kW element alone it will of course hold 100*C fine.  Unfortunately with a high enough evapouration rate that it literally rains beer afterwards from the cieling.  About 5 litres of beer turns into rain.

So temperature regulation is out.  If I needed temp regulation I could use the built in bi-metalic thermostat.

A PWM controller that supports a direct duty cycle setting would be more appropriate.

I assume by "process controller" we are referring to the little modules with red led displays and outputs for driving relays etc.?

There are the expensive real ones (is it STC1000?) and then there are the cheap copies.  I assum the later still work fine as they are very popular?

One of those which has a high enough output voltage to control, say, a 20A SSR ...  just the question about "non-temperature manually variably PWM" availability.

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