Honeywell programmer

I have a Honeywell ST6400C programmer for heating & hot water.

Most of the time, hot water is set to 'off', and when I need hot water I press the 'extra hour' button for a full cylinder of hot water.

However, someties when I hit the button, the entire programmer goes off - all lights out, display goes blank. After mayber 2, 3 seconds there's a click & it restarts (back at previous setting).

This does not always happen, and I can see no pattern as to when it will work, or cut out.

Usually pressing 'extra hour' again works, though occassionally it will cut out a 2nd time.

My questions are:

1) what might be the cause & is it an easy fix?

2) if it needs replacing, I'm sure it is an obsolete model, but if there's a comparable replacement model, does it need a sparkie/heating engineer to change (lotsof wiring inside?) or do they unscrew, pull off, push on repacement and screw up?

Cheers.

Have you checked that the front panel is firmly pushed and secured into the back plate, or for a loose live wire?

There are several models that will fit straight onto the existing back plate, including Honeywell's current version of that programmer (ST9400c I think) should you decide to replace.

Mike_e said:

or do they unscrew, pull off, push on repacement and screw up?

Click to expand...

Yes they do