some 6mm and 8mm microbore, a 1/2" bsp backnut, 1/2" bsp plug and a dodgy homemade silicon washer
pipes cut, plug drilled with 8mm hole, 6mm pinched at tip, assembled, tip and other joints soldered... TADA!! a thermowell which fits perfectly in the hole left by taking out the burco tap. Element turned so as not to leave it directly under the thermowell tip.
Burco upside down, cover plate removed and two 21mm holes q'maxed, one in side skirt, one in boiler bottom
tank connector fitted using supplied washer on the outside, and another homemade silicon washer inside the boiler, 15mm tube attached and brought through side hole, tee fitted to take sight tube and tap attached. Outside of thermowell visible too.
Skirt masking taped, marked with size of temp controller, drilled, jigsawed, and finally filed to size. Allow enough space inside so the controller doesn't hit anything else. Thermowell socket clearly seen. 6mm pipe used at tip because thermoprobe supplied with controller was about 4.5mm diameter and with the tip pinched to seal it, the probe coulfd be pushed in and would catch at the end giving a good thermal contact.
2nd hole cut for mains switch, switch and controller fitted, old simmerstat removed. Double thickness of camping foam mat cut and fitted outlet pipe insulated, bits of foam wedged in to stop foam discs falling away from base when in use. BTW the curved "earth" thingy is actually a metal strip from a windscreen wiper blade insulated for safety and used as a spring to help keep the insulation in place.
Electrics:
1. L & N wires to switch,
2. N from switch to controller and also to N connector on element
3. L from switch to L on controller and L side of relay (marked load on controller)
4. Switchable feed from 2nd controller relay terminal to L terminal on burco element
5. Thermoprobe connected to controller and fed out through now unused simmerstat hole to thermowell
Still with me?
Burco upright, sight glass fitted, more insulation, thermoprobe wire visible going into thermowell, water in tank, powered up and heating on, yay it all works!.
Oh, nearly all works, electrics, controller and thermoprobe work perfectly, but due to venturi effect (thanks for the info chastuck) the sight glass empties the moment you open the tap. I wasn't able to take advantage of chastucks advice on this so;
2nd pair of holes q'maxed to fit another tank connector specifically for the tap
Finally reassembled again, separate tap connection, sight glass now on an elbow, problem fixed.
In use;
Controller set for a 2 degree 'slew' by default, switches off at set temp. with residual heat/convection it seems to rise about another 1.5 degrees, power is kept off until it drops to 2 degrees below set figure when it switches back on. If you set the controller to 101c it keeps a rolling boil going. I think you can alter the slew figure from 2 degrees if need be, it seems to suit me fine though.
Hope this is of some use to people!
one thing i noticed after leaving a hlt under electronic control, is the water at the probe was spot on the temp set, but above and below the water had settled into layers at different temps, SO a good stir before you start pouring is well worth it to dbl check, many go further and recirculate or add mechanical stirrers to overcome this, a quick stir is a much cheaper n easier solution tho..
