Hot End Temperature Not Updating

I have an issues I was hoping someone could help with.

I have just installed an E3DV6 hotend on my printer with a Duet 0.8 board. In the config I have:

M305 P1 T100000 B4388 R4700 H0 L0

On the web interface I am seeing a temperature of 168C as soon as the printer turns on. I have tried tweaking the T value all the way down to T1000 and at T1000 I get room temperature(or close to it) to read. When I tell the heater to activate though, the temperature reading never changes. It will heat all the way to 170 and start melting my PLA without so much as a degree change in the temperature reading.

Any ideas what I am doing wrong?

My guess is that you have a fault in your thermistor wiring. Check that the therrmistor wires are not shorting against the heater block or anything else. If you have a multimeter, unplug the thermistor connector from the Duet, poke a couple of wires into it, and measure the resistance. It should be around 100K at room temperature. If you power up the Duet with the thermistor disconnected (USB power is sufficient), it should either give a temperature error on heater 1 or it should report a negative temperature.

The normal range for the H and L parameters is +/- 30.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].