How to set Landis & Steafa RW89 onto auto?

I have a Landis & Steafa RW89 control and it has been wired incorrectly so the heating can only work if the water is on. Last time an engineer came he set it so the water was on constantly. The problem is that every time the water reaches the correct temperature the heating goes off (generally about 9 so not noticed until too late). I have reset it so the water is only on when the heating is but it is defaulting to OFF instead of AUTO. Any suggestions?