I kept the "old" DKO970 when the engineer fitted a new, allegedly
compatible, TF 832.3 in its place a couple of weeks ago.

I have my suspicions about whether the new TF 832.3 *IS* truly
compatible with the DKO970, since the DKO970 is for a 1-stage burner
whereas the TF 832.3 is for a 2-stage burner. The Handbook does
specify a DKO970.

So, since the boiler is functioning perfectly in all respects OTHER
than the intermittent problem of lockout after approx 30 minutes when
the boiler started from stone cold, I have decided to put the DKO970
back temporarily.

Can I do this myself (ex motor fitter!)?

This looks like an easy job, right?

The Plan:

Switch the Danfoss to OFF for both heating and hot water, disconnect
the power supply to the control box (a push connector on white cable),
release the single retaining screw, pull off the current control box,
push on the DKO970, ensuring spade terminals engage correctly, tighten
screw, reconnect power supply, switch Danfoss back to AUTO.

Does that sound okay?

MM