Maxi Controlling FV Temp`s

[BenB]

where the pump is controlled by both the heat and the cool power. How does this work?

spdt /change over relay, common to the pump,coil and 1 side of the switch to cooling power,other side of switch to heating power. when the unit is calling for cooling the relay energise and switches the pump over to the cooling power rail,when its calling for heating the relay de -energise and connects the pump to the heating power rail, use a double pole relay and you can switch the neutrals as well

Beat me to it

[chris2012]

Just ordered a stc1000, to try and copy your setup

Just a little question, am I right in thinking in your setup, you disconnect the compressor and take the wires that were
going to the compressor, to the stc1000, then the cool side output of the stc1000 to the compressor?

(Whilst leaving the pump etc. connected as is)

cheers

Chris

[Fil]

Just ordered a stc1000, to try and copy your setup

Just a little question, am I right in thinking in your setup, you disconnect the compressor and take the wires that were
going to the compressor, to the stc1000, then the cool side output of the stc1000 to the compressor?

(Whilst leaving the pump etc. connected as is)

cheers

Chris

If employing a heat pipe too then the pump wants to be run if either heating or cooling is employed, and off when neither are needed..

If just employing the chiller for cooling then the pump/compressor can be switched with the same relay ok..

hope that helps...

[chris2012]

Oh, I was under the impression the pump is on all the time - regardless if you're heating or cooling or not doing anything.

[Fil]

Unless you can guarantee the waterbath is maintained at a temperature + or - the ?known? loss in transfer to the coil, continual running of the pump will in all probability over/under-shoot the target temp in the FV as the waterbath/(temperature store) normalises with the temp of the fermentors mass. Running the pump will continue the heat exchange until both fv and waterbath are at an equilibrium which will probably be significantly off the FV target temp.

[chris2012]

I've just realised you probably can't use an STC1000 to switch on/off the pump, when
either heating or cooling, as you'd need some kind of high voltage 'or' gate, at least as
far as I can tell.

I might possibly use an MCU+SSRs instead possibly.

[Fil]

some chaps have fitted fancy secondary power relays to overcome this, i went low dc voltage..

using a 5v phone charger and http://www.ebay.co.uk/itm/1x-4-Channel- ... 3d02c9a006

and simply wiring the compressor, and heat tube and pump (x2) to be switched by the relay board. the stc relays switching the 5v dc current suppiled from the phone charger to switch the pump and compressor relays on the board when the cooling relay on the stc closes or to switch the heater and pump relays when heating is required,switched by the stc1000 heating relay closing,

if using a heat pipe i would also add a Normally closed thermal switch strapped or botled to the tube heater or just after it, in its power circuit set to trigger at 35-40C to avoid overheating the water in circulation. http://www.ebay.co.uk/itm/5pcs-KSD301-T ... 4ae7fd1a39
if using a low power heater it may be unnecessary?

[chris2012]

Ooh cheers, i've never seen a thermal switch before, sounds like a good idea.

[themadhippy]

I've just realised you probably can't use an STC1000 to switch on/off the pump, when
either heating or cooling, as you'd need some kind of high voltage 'or' gate, at least as
far as I can tell.

Na just a simple relay will work the magic

when the stc isnt calling for either heat or cold theres no power to fire the pump,in cooling the relay wont energise so power for the pump comes from the cooling circuit,when calling for heat the relay energises and switches the pumps power to the heat line

[chris2012]

Nice, that's very nifty, cheers

[chris2012]

Looking at the diagram you posted, I assume I'm right in thinking the pump uses mains voltage?

I'm just about to order a couple of SSRs etc, to knock something up with an MCU + ESP8266 probably, so I can monitor and control my
fermentation temp