fermentation temp

[Normski]

Hi Neil
It may be worth trying an ATC 800+ or similar to control the power to the heater.
They switch + & - 1c.
What amp does your heater draw.
ATC800 Relay contact capacity: Cool (20A/250VAC); Heat (10A/250VAC)

Norm

[gregorach]

You're going to have quite a large overshoot with that much thermal mass... The actual temperature range will be larger in practice, possibly several degrees larger. Temperature control on large volumes gets tricky. I would certainly think you'd be better off with a separate controller with a narrower range, but then I'm obsessive about temperature control...

[Eric]

I have two such heaters, 300W and 500W, used in the way described earlier. They work in a fashion good enough for 23 litre batches at my standards, but as Dunc says, with 220 litres of fermenting ale you can have a substantial amount of thermal inertia. 40 litres in a 220 litre pot has its own problems too, such heaters may not be designed for use in shallow vessels, maybe just 12 cm of fluid in the case you quote.
Good luck.

[critch]

my controller has a 0.1.c varience im brewing more than you and i sodding need it

a few times ive come in to 21.c beer with a full chat chiller

crying, wailing and gnashing of teeth have occured

although it turned out nice in the end!

[neil smith]

thanks all, i have just ordered a pid controller and 25a relay so will put heaters through it i have 2, and in the summer i can put my chiller through it and will have much more accurate temp control, i can lay the heaters on their side if only doing small batches.
cheers Neil