Swapping relay on MK138

Hi,

If i wanted to swap the relay on the MK138 for the following to stop relay chatter (see my previous question - viewtopic.php?f=7&t=7619)

velleman.eu/products/view/?c … &id=341825

How would i go about connecting it up.

Thanks

Mark

Measure relay coil polarity on MK138.
Remove relay and connect solid state relay input. Mind the polarity.
Connect load in series with solid state relay output.

I think i must have done something wrong. I connected the relay as follows

C1 - input +
C2 - Input -
COM - Output 1
NO - Output 2

The relay doesnt seem to turn off when temperature is reached. I have tried shorting the contacts on the sensor but nothing happens. The LED on the board is on continuously.

If i start the unit with the relay disconnected the lights are off (so the relay switch is not stuck on). However, as soon as i give the relay power, the lights stay on no matter what. even disconnecting the power input on the relay coil does not make a difference

Any ideas?