next part of my build...probes for boiler and HLT

[FOPA]

Please BE CAREFUL with advice as to using a STC1000 to control electric heating elements. STC1000 are rated to 10A input and output, using the formula watts/voltage = amps.... a 2.2kw element will draw 9.2Amp@240v which is very close to the limit, the more normal 2.4kw element will draw 10A and a 2.75kw 11.5A. You'd be best to consider a PID unit to control an element.

I used an STC1000 to control a 3kW Burco heater. I used the 10A relay on the STC1000 to switch the "gate" voltage to the Triac on a 4.5kW "dimmer" unit (also available really cheap on eBay). That way the STC1000 is easily man enough for the job, and I can also turn down the Burco power once I'm close to target HLT temp, minimising overshoot. I can also use the dimmer to stabilise a rolling boil when the Burco is in use as a boiler, helping to prevent boil over. It's a real cheap and flexible solution, as long as you're OK to cut the PCB track on the dimmer unit and solder a couple of wires on to bridge the gap with the STC1000's relay.

 

[Springer]

I still don't know if PT100s require a thermowell, but got my ideas together on various mounting options, I will be using thermowells just to be on the safe side.

For a PT100 in a flow.
Top one is a turned down m8 nut to be soldered into 15/10mm reducer and then copper tee.

For tank mounting
Middle one, a modified tank fitting, with a brass bush drilled 8mm for thermowell and tapped m8 for PT100 . Could be used
with or without thermowell for PT100 and with thermowell for other senders.

Another way for flow mounting
Turned down reducer soldered into a copper fitting and plug taped m8, again could be used with or without thermowell for PT100 and with thermowell for a other senders.
Just my ideas.

S