TheMadHopper wrote: Are you saying that these things are capable of running an electric HLT?
Yes, they are with the understanding that they are differential mode controllers which means that if you set the controller for 50 °C it will come on and stay on until the temperature reached 50 plus the differential. The smallest differential for this unit is 0.3 °C (0.54 °F) so this means that, assuming the minimum differential, the heater will stay on until 50.3 °C is reached and then turn off. As the heating element will still be hotter than the water (or mash or whatever you are controlling the temperature of) when the power is switched off the temperature will continue to rise somewhat beyond 50.3 and then begin to decline as the water cools. The heater will stay off until the temperature reaches 50 °C at which time the heater is switched back on and the cycle repeats. Thus a plot of the temperature will show a series of triangles or sawteeth with peak to trough difference equal to the differential setting plus a little. This is certainly aceeptable in some applications (such as controlling a refrigeration system or turning glycol flow on and off to a fermenter's jacket(s) and in fact probably quite acceptable for RIMS, HERMS or conventional mash tun control but some people may want tighter, more unifiorm control of temperature. For them the more expensive (and difficult to set up) PID controllers are the way to go.
A SSR will absolutely be required if the heater draws more than the contact ratings on the unit and probably a good idea even if it draws less. Using one allows you to do all your "control" wiring at low voltage (though the device itself is powered by a mains connection).
